The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_page.c

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    1 /*-
    2  * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU)
    3  *
    4  * Copyright (c) 1991 Regents of the University of California.
    5  * All rights reserved.
    6  * Copyright (c) 1998 Matthew Dillon.  All Rights Reserved.
    7  *
    8  * This code is derived from software contributed to Berkeley by
    9  * The Mach Operating System project at Carnegie-Mellon University.
   10  *
   11  * Redistribution and use in source and binary forms, with or without
   12  * modification, are permitted provided that the following conditions
   13  * are met:
   14  * 1. Redistributions of source code must retain the above copyright
   15  *    notice, this list of conditions and the following disclaimer.
   16  * 2. Redistributions in binary form must reproduce the above copyright
   17  *    notice, this list of conditions and the following disclaimer in the
   18  *    documentation and/or other materials provided with the distribution.
   19  * 3. Neither the name of the University nor the names of its contributors
   20  *    may be used to endorse or promote products derived from this software
   21  *    without specific prior written permission.
   22  *
   23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   33  * SUCH DAMAGE.
   34  *
   35  *      from: @(#)vm_page.c     7.4 (Berkeley) 5/7/91
   36  */
   37 
   38 /*-
   39  * Copyright (c) 1987, 1990 Carnegie-Mellon University.
   40  * All rights reserved.
   41  *
   42  * Authors: Avadis Tevanian, Jr., Michael Wayne Young
   43  *
   44  * Permission to use, copy, modify and distribute this software and
   45  * its documentation is hereby granted, provided that both the copyright
   46  * notice and this permission notice appear in all copies of the
   47  * software, derivative works or modified versions, and any portions
   48  * thereof, and that both notices appear in supporting documentation.
   49  *
   50  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
   51  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
   52  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
   53  *
   54  * Carnegie Mellon requests users of this software to return to
   55  *
   56  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
   57  *  School of Computer Science
   58  *  Carnegie Mellon University
   59  *  Pittsburgh PA 15213-3890
   60  *
   61  * any improvements or extensions that they make and grant Carnegie the
   62  * rights to redistribute these changes.
   63  */
   64 
   65 /*
   66  *      Resident memory management module.
   67  */
   68 
   69 #include <sys/cdefs.h>
   70 __FBSDID("$FreeBSD$");
   71 
   72 #include "opt_vm.h"
   73 
   74 #include <sys/param.h>
   75 #include <sys/systm.h>
   76 #include <sys/counter.h>
   77 #include <sys/domainset.h>
   78 #include <sys/kernel.h>
   79 #include <sys/limits.h>
   80 #include <sys/linker.h>
   81 #include <sys/lock.h>
   82 #include <sys/malloc.h>
   83 #include <sys/mman.h>
   84 #include <sys/msgbuf.h>
   85 #include <sys/mutex.h>
   86 #include <sys/proc.h>
   87 #include <sys/rwlock.h>
   88 #include <sys/sleepqueue.h>
   89 #include <sys/sbuf.h>
   90 #include <sys/sched.h>
   91 #include <sys/smp.h>
   92 #include <sys/sysctl.h>
   93 #include <sys/vmmeter.h>
   94 #include <sys/vnode.h>
   95 
   96 #include <vm/vm.h>
   97 #include <vm/pmap.h>
   98 #include <vm/vm_param.h>
   99 #include <vm/vm_domainset.h>
  100 #include <vm/vm_kern.h>
  101 #include <vm/vm_map.h>
  102 #include <vm/vm_object.h>
  103 #include <vm/vm_page.h>
  104 #include <vm/vm_pageout.h>
  105 #include <vm/vm_phys.h>
  106 #include <vm/vm_pagequeue.h>
  107 #include <vm/vm_pager.h>
  108 #include <vm/vm_radix.h>
  109 #include <vm/vm_reserv.h>
  110 #include <vm/vm_extern.h>
  111 #include <vm/vm_dumpset.h>
  112 #include <vm/uma.h>
  113 #include <vm/uma_int.h>
  114 
  115 #include <machine/md_var.h>
  116 
  117 struct vm_domain vm_dom[MAXMEMDOM];
  118 
  119 DPCPU_DEFINE_STATIC(struct vm_batchqueue, pqbatch[MAXMEMDOM][PQ_COUNT]);
  120 
  121 struct mtx_padalign __exclusive_cache_line pa_lock[PA_LOCK_COUNT];
  122 
  123 struct mtx_padalign __exclusive_cache_line vm_domainset_lock;
  124 /* The following fields are protected by the domainset lock. */
  125 domainset_t __exclusive_cache_line vm_min_domains;
  126 domainset_t __exclusive_cache_line vm_severe_domains;
  127 static int vm_min_waiters;
  128 static int vm_severe_waiters;
  129 static int vm_pageproc_waiters;
  130 
  131 static SYSCTL_NODE(_vm_stats, OID_AUTO, page, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
  132     "VM page statistics");
  133 
  134 static COUNTER_U64_DEFINE_EARLY(pqstate_commit_retries);
  135 SYSCTL_COUNTER_U64(_vm_stats_page, OID_AUTO, pqstate_commit_retries,
  136     CTLFLAG_RD, &pqstate_commit_retries,
  137     "Number of failed per-page atomic queue state updates");
  138 
  139 static COUNTER_U64_DEFINE_EARLY(queue_ops);
  140 SYSCTL_COUNTER_U64(_vm_stats_page, OID_AUTO, queue_ops,
  141     CTLFLAG_RD, &queue_ops,
  142     "Number of batched queue operations");
  143 
  144 static COUNTER_U64_DEFINE_EARLY(queue_nops);
  145 SYSCTL_COUNTER_U64(_vm_stats_page, OID_AUTO, queue_nops,
  146     CTLFLAG_RD, &queue_nops,
  147     "Number of batched queue operations with no effects");
  148 
  149 /*
  150  * bogus page -- for I/O to/from partially complete buffers,
  151  * or for paging into sparsely invalid regions.
  152  */
  153 vm_page_t bogus_page;
  154 
  155 vm_page_t vm_page_array;
  156 long vm_page_array_size;
  157 long first_page;
  158 
  159 struct bitset *vm_page_dump;
  160 long vm_page_dump_pages;
  161 
  162 static TAILQ_HEAD(, vm_page) blacklist_head;
  163 static int sysctl_vm_page_blacklist(SYSCTL_HANDLER_ARGS);
  164 SYSCTL_PROC(_vm, OID_AUTO, page_blacklist, CTLTYPE_STRING | CTLFLAG_RD |
  165     CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_page_blacklist, "A", "Blacklist pages");
  166 
  167 static uma_zone_t fakepg_zone;
  168 
  169 static void vm_page_alloc_check(vm_page_t m);
  170 static bool _vm_page_busy_sleep(vm_object_t obj, vm_page_t m,
  171     vm_pindex_t pindex, const char *wmesg, int allocflags, bool locked);
  172 static void vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits);
  173 static void vm_page_enqueue(vm_page_t m, uint8_t queue);
  174 static bool vm_page_free_prep(vm_page_t m);
  175 static void vm_page_free_toq(vm_page_t m);
  176 static void vm_page_init(void *dummy);
  177 static int vm_page_insert_after(vm_page_t m, vm_object_t object,
  178     vm_pindex_t pindex, vm_page_t mpred);
  179 static void vm_page_insert_radixdone(vm_page_t m, vm_object_t object,
  180     vm_page_t mpred);
  181 static void vm_page_mvqueue(vm_page_t m, const uint8_t queue,
  182     const uint16_t nflag);
  183 static int vm_page_reclaim_run(int req_class, int domain, u_long npages,
  184     vm_page_t m_run, vm_paddr_t high);
  185 static void vm_page_release_toq(vm_page_t m, uint8_t nqueue, bool noreuse);
  186 static int vm_domain_alloc_fail(struct vm_domain *vmd, vm_object_t object,
  187     int req);
  188 static int vm_page_zone_import(void *arg, void **store, int cnt, int domain,
  189     int flags);
  190 static void vm_page_zone_release(void *arg, void **store, int cnt);
  191 
  192 SYSINIT(vm_page, SI_SUB_VM, SI_ORDER_SECOND, vm_page_init, NULL);
  193 
  194 static void
  195 vm_page_init(void *dummy)
  196 {
  197 
  198         fakepg_zone = uma_zcreate("fakepg", sizeof(struct vm_page), NULL, NULL,
  199             NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
  200         bogus_page = vm_page_alloc(NULL, 0, VM_ALLOC_NOOBJ |
  201             VM_ALLOC_NORMAL | VM_ALLOC_WIRED);
  202 }
  203 
  204 /*
  205  * The cache page zone is initialized later since we need to be able to allocate
  206  * pages before UMA is fully initialized.
  207  */
  208 static void
  209 vm_page_init_cache_zones(void *dummy __unused)
  210 {
  211         struct vm_domain *vmd;
  212         struct vm_pgcache *pgcache;
  213         int cache, domain, maxcache, pool;
  214 
  215         maxcache = 0;
  216         TUNABLE_INT_FETCH("vm.pgcache_zone_max_pcpu", &maxcache);
  217         maxcache *= mp_ncpus;
  218         for (domain = 0; domain < vm_ndomains; domain++) {
  219                 vmd = VM_DOMAIN(domain);
  220                 for (pool = 0; pool < VM_NFREEPOOL; pool++) {
  221                         pgcache = &vmd->vmd_pgcache[pool];
  222                         pgcache->domain = domain;
  223                         pgcache->pool = pool;
  224                         pgcache->zone = uma_zcache_create("vm pgcache",
  225                             PAGE_SIZE, NULL, NULL, NULL, NULL,
  226                             vm_page_zone_import, vm_page_zone_release, pgcache,
  227                             UMA_ZONE_VM);
  228 
  229                         /*
  230                          * Limit each pool's zone to 0.1% of the pages in the
  231                          * domain.
  232                          */
  233                         cache = maxcache != 0 ? maxcache :
  234                             vmd->vmd_page_count / 1000;
  235                         uma_zone_set_maxcache(pgcache->zone, cache);
  236                 }
  237         }
  238 }
  239 SYSINIT(vm_page2, SI_SUB_VM_CONF, SI_ORDER_ANY, vm_page_init_cache_zones, NULL);
  240 
  241 /* Make sure that u_long is at least 64 bits when PAGE_SIZE is 32K. */
  242 #if PAGE_SIZE == 32768
  243 #ifdef CTASSERT
  244 CTASSERT(sizeof(u_long) >= 8);
  245 #endif
  246 #endif
  247 
  248 /*
  249  *      vm_set_page_size:
  250  *
  251  *      Sets the page size, perhaps based upon the memory
  252  *      size.  Must be called before any use of page-size
  253  *      dependent functions.
  254  */
  255 void
  256 vm_set_page_size(void)
  257 {
  258         if (vm_cnt.v_page_size == 0)
  259                 vm_cnt.v_page_size = PAGE_SIZE;
  260         if (((vm_cnt.v_page_size - 1) & vm_cnt.v_page_size) != 0)
  261                 panic("vm_set_page_size: page size not a power of two");
  262 }
  263 
  264 /*
  265  *      vm_page_blacklist_next:
  266  *
  267  *      Find the next entry in the provided string of blacklist
  268  *      addresses.  Entries are separated by space, comma, or newline.
  269  *      If an invalid integer is encountered then the rest of the
  270  *      string is skipped.  Updates the list pointer to the next
  271  *      character, or NULL if the string is exhausted or invalid.
  272  */
  273 static vm_paddr_t
  274 vm_page_blacklist_next(char **list, char *end)
  275 {
  276         vm_paddr_t bad;
  277         char *cp, *pos;
  278 
  279         if (list == NULL || *list == NULL)
  280                 return (0);
  281         if (**list =='\0') {
  282                 *list = NULL;
  283                 return (0);
  284         }
  285 
  286         /*
  287          * If there's no end pointer then the buffer is coming from
  288          * the kenv and we know it's null-terminated.
  289          */
  290         if (end == NULL)
  291                 end = *list + strlen(*list);
  292 
  293         /* Ensure that strtoq() won't walk off the end */
  294         if (*end != '\0') {
  295                 if (*end == '\n' || *end == ' ' || *end  == ',')
  296                         *end = '\0';
  297                 else {
  298                         printf("Blacklist not terminated, skipping\n");
  299                         *list = NULL;
  300                         return (0);
  301                 }
  302         }
  303 
  304         for (pos = *list; *pos != '\0'; pos = cp) {
  305                 bad = strtoq(pos, &cp, 0);
  306                 if (*cp == '\0' || *cp == ' ' || *cp == ',' || *cp == '\n') {
  307                         if (bad == 0) {
  308                                 if (++cp < end)
  309                                         continue;
  310                                 else
  311                                         break;
  312                         }
  313                 } else
  314                         break;
  315                 if (*cp == '\0' || ++cp >= end)
  316                         *list = NULL;
  317                 else
  318                         *list = cp;
  319                 return (trunc_page(bad));
  320         }
  321         printf("Garbage in RAM blacklist, skipping\n");
  322         *list = NULL;
  323         return (0);
  324 }
  325 
  326 bool
  327 vm_page_blacklist_add(vm_paddr_t pa, bool verbose)
  328 {
  329         struct vm_domain *vmd;
  330         vm_page_t m;
  331         int ret;
  332 
  333         m = vm_phys_paddr_to_vm_page(pa);
  334         if (m == NULL)
  335                 return (true); /* page does not exist, no failure */
  336 
  337         vmd = vm_pagequeue_domain(m);
  338         vm_domain_free_lock(vmd);
  339         ret = vm_phys_unfree_page(m);
  340         vm_domain_free_unlock(vmd);
  341         if (ret != 0) {
  342                 vm_domain_freecnt_inc(vmd, -1);
  343                 TAILQ_INSERT_TAIL(&blacklist_head, m, listq);
  344                 if (verbose)
  345                         printf("Skipping page with pa 0x%jx\n", (uintmax_t)pa);
  346         }
  347         return (ret);
  348 }
  349 
  350 /*
  351  *      vm_page_blacklist_check:
  352  *
  353  *      Iterate through the provided string of blacklist addresses, pulling
  354  *      each entry out of the physical allocator free list and putting it
  355  *      onto a list for reporting via the vm.page_blacklist sysctl.
  356  */
  357 static void
  358 vm_page_blacklist_check(char *list, char *end)
  359 {
  360         vm_paddr_t pa;
  361         char *next;
  362 
  363         next = list;
  364         while (next != NULL) {
  365                 if ((pa = vm_page_blacklist_next(&next, end)) == 0)
  366                         continue;
  367                 vm_page_blacklist_add(pa, bootverbose);
  368         }
  369 }
  370 
  371 /*
  372  *      vm_page_blacklist_load:
  373  *
  374  *      Search for a special module named "ram_blacklist".  It'll be a
  375  *      plain text file provided by the user via the loader directive
  376  *      of the same name.
  377  */
  378 static void
  379 vm_page_blacklist_load(char **list, char **end)
  380 {
  381         void *mod;
  382         u_char *ptr;
  383         u_int len;
  384 
  385         mod = NULL;
  386         ptr = NULL;
  387 
  388         mod = preload_search_by_type("ram_blacklist");
  389         if (mod != NULL) {
  390                 ptr = preload_fetch_addr(mod);
  391                 len = preload_fetch_size(mod);
  392         }
  393         *list = ptr;
  394         if (ptr != NULL)
  395                 *end = ptr + len;
  396         else
  397                 *end = NULL;
  398         return;
  399 }
  400 
  401 static int
  402 sysctl_vm_page_blacklist(SYSCTL_HANDLER_ARGS)
  403 {
  404         vm_page_t m;
  405         struct sbuf sbuf;
  406         int error, first;
  407 
  408         first = 1;
  409         error = sysctl_wire_old_buffer(req, 0);
  410         if (error != 0)
  411                 return (error);
  412         sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
  413         TAILQ_FOREACH(m, &blacklist_head, listq) {
  414                 sbuf_printf(&sbuf, "%s%#jx", first ? "" : ",",
  415                     (uintmax_t)m->phys_addr);
  416                 first = 0;
  417         }
  418         error = sbuf_finish(&sbuf);
  419         sbuf_delete(&sbuf);
  420         return (error);
  421 }
  422 
  423 /*
  424  * Initialize a dummy page for use in scans of the specified paging queue.
  425  * In principle, this function only needs to set the flag PG_MARKER.
  426  * Nonetheless, it write busies the page as a safety precaution.
  427  */
  428 void
  429 vm_page_init_marker(vm_page_t marker, int queue, uint16_t aflags)
  430 {
  431 
  432         bzero(marker, sizeof(*marker));
  433         marker->flags = PG_MARKER;
  434         marker->a.flags = aflags;
  435         marker->busy_lock = VPB_CURTHREAD_EXCLUSIVE;
  436         marker->a.queue = queue;
  437 }
  438 
  439 static void
  440 vm_page_domain_init(int domain)
  441 {
  442         struct vm_domain *vmd;
  443         struct vm_pagequeue *pq;
  444         int i;
  445 
  446         vmd = VM_DOMAIN(domain);
  447         bzero(vmd, sizeof(*vmd));
  448         *__DECONST(const char **, &vmd->vmd_pagequeues[PQ_INACTIVE].pq_name) =
  449             "vm inactive pagequeue";
  450         *__DECONST(const char **, &vmd->vmd_pagequeues[PQ_ACTIVE].pq_name) =
  451             "vm active pagequeue";
  452         *__DECONST(const char **, &vmd->vmd_pagequeues[PQ_LAUNDRY].pq_name) =
  453             "vm laundry pagequeue";
  454         *__DECONST(const char **,
  455             &vmd->vmd_pagequeues[PQ_UNSWAPPABLE].pq_name) =
  456             "vm unswappable pagequeue";
  457         vmd->vmd_domain = domain;
  458         vmd->vmd_page_count = 0;
  459         vmd->vmd_free_count = 0;
  460         vmd->vmd_segs = 0;
  461         vmd->vmd_oom = FALSE;
  462         for (i = 0; i < PQ_COUNT; i++) {
  463                 pq = &vmd->vmd_pagequeues[i];
  464                 TAILQ_INIT(&pq->pq_pl);
  465                 mtx_init(&pq->pq_mutex, pq->pq_name, "vm pagequeue",
  466                     MTX_DEF | MTX_DUPOK);
  467                 pq->pq_pdpages = 0;
  468                 vm_page_init_marker(&vmd->vmd_markers[i], i, 0);
  469         }
  470         mtx_init(&vmd->vmd_free_mtx, "vm page free queue", NULL, MTX_DEF);
  471         mtx_init(&vmd->vmd_pageout_mtx, "vm pageout lock", NULL, MTX_DEF);
  472         snprintf(vmd->vmd_name, sizeof(vmd->vmd_name), "%d", domain);
  473 
  474         /*
  475          * inacthead is used to provide FIFO ordering for LRU-bypassing
  476          * insertions.
  477          */
  478         vm_page_init_marker(&vmd->vmd_inacthead, PQ_INACTIVE, PGA_ENQUEUED);
  479         TAILQ_INSERT_HEAD(&vmd->vmd_pagequeues[PQ_INACTIVE].pq_pl,
  480             &vmd->vmd_inacthead, plinks.q);
  481 
  482         /*
  483          * The clock pages are used to implement active queue scanning without
  484          * requeues.  Scans start at clock[0], which is advanced after the scan
  485          * ends.  When the two clock hands meet, they are reset and scanning
  486          * resumes from the head of the queue.
  487          */
  488         vm_page_init_marker(&vmd->vmd_clock[0], PQ_ACTIVE, PGA_ENQUEUED);
  489         vm_page_init_marker(&vmd->vmd_clock[1], PQ_ACTIVE, PGA_ENQUEUED);
  490         TAILQ_INSERT_HEAD(&vmd->vmd_pagequeues[PQ_ACTIVE].pq_pl,
  491             &vmd->vmd_clock[0], plinks.q);
  492         TAILQ_INSERT_TAIL(&vmd->vmd_pagequeues[PQ_ACTIVE].pq_pl,
  493             &vmd->vmd_clock[1], plinks.q);
  494 }
  495 
  496 /*
  497  * Initialize a physical page in preparation for adding it to the free
  498  * lists.
  499  */
  500 static void
  501 vm_page_init_page(vm_page_t m, vm_paddr_t pa, int segind)
  502 {
  503 
  504         m->object = NULL;
  505         m->ref_count = 0;
  506         m->busy_lock = VPB_FREED;
  507         m->flags = m->a.flags = 0;
  508         m->phys_addr = pa;
  509         m->a.queue = PQ_NONE;
  510         m->psind = 0;
  511         m->segind = segind;
  512         m->order = VM_NFREEORDER;
  513         m->pool = VM_FREEPOOL_DEFAULT;
  514         m->valid = m->dirty = 0;
  515         pmap_page_init(m);
  516 }
  517 
  518 #ifndef PMAP_HAS_PAGE_ARRAY
  519 static vm_paddr_t
  520 vm_page_array_alloc(vm_offset_t *vaddr, vm_paddr_t end, vm_paddr_t page_range)
  521 {
  522         vm_paddr_t new_end;
  523 
  524         /*
  525          * Reserve an unmapped guard page to trap access to vm_page_array[-1].
  526          * However, because this page is allocated from KVM, out-of-bounds
  527          * accesses using the direct map will not be trapped.
  528          */
  529         *vaddr += PAGE_SIZE;
  530 
  531         /*
  532          * Allocate physical memory for the page structures, and map it.
  533          */
  534         new_end = trunc_page(end - page_range * sizeof(struct vm_page));
  535         vm_page_array = (vm_page_t)pmap_map(vaddr, new_end, end,
  536             VM_PROT_READ | VM_PROT_WRITE);
  537         vm_page_array_size = page_range;
  538 
  539         return (new_end);
  540 }
  541 #endif
  542 
  543 /*
  544  *      vm_page_startup:
  545  *
  546  *      Initializes the resident memory module.  Allocates physical memory for
  547  *      bootstrapping UMA and some data structures that are used to manage
  548  *      physical pages.  Initializes these structures, and populates the free
  549  *      page queues.
  550  */
  551 vm_offset_t
  552 vm_page_startup(vm_offset_t vaddr)
  553 {
  554         struct vm_phys_seg *seg;
  555         vm_page_t m;
  556         char *list, *listend;
  557         vm_paddr_t end, high_avail, low_avail, new_end, size;
  558         vm_paddr_t page_range __unused;
  559         vm_paddr_t last_pa, pa;
  560         u_long pagecount;
  561 #if MINIDUMP_PAGE_TRACKING
  562         u_long vm_page_dump_size;
  563 #endif
  564         int biggestone, i, segind;
  565 #ifdef WITNESS
  566         vm_offset_t mapped;
  567         int witness_size;
  568 #endif
  569 #if defined(__i386__) && defined(VM_PHYSSEG_DENSE)
  570         long ii;
  571 #endif
  572 
  573         vaddr = round_page(vaddr);
  574 
  575         vm_phys_early_startup();
  576         biggestone = vm_phys_avail_largest();
  577         end = phys_avail[biggestone+1];
  578 
  579         /*
  580          * Initialize the page and queue locks.
  581          */
  582         mtx_init(&vm_domainset_lock, "vm domainset lock", NULL, MTX_DEF);
  583         for (i = 0; i < PA_LOCK_COUNT; i++)
  584                 mtx_init(&pa_lock[i], "vm page", NULL, MTX_DEF);
  585         for (i = 0; i < vm_ndomains; i++)
  586                 vm_page_domain_init(i);
  587 
  588         new_end = end;
  589 #ifdef WITNESS
  590         witness_size = round_page(witness_startup_count());
  591         new_end -= witness_size;
  592         mapped = pmap_map(&vaddr, new_end, new_end + witness_size,
  593             VM_PROT_READ | VM_PROT_WRITE);
  594         bzero((void *)mapped, witness_size);
  595         witness_startup((void *)mapped);
  596 #endif
  597 
  598 #if MINIDUMP_PAGE_TRACKING
  599         /*
  600          * Allocate a bitmap to indicate that a random physical page
  601          * needs to be included in a minidump.
  602          *
  603          * The amd64 port needs this to indicate which direct map pages
  604          * need to be dumped, via calls to dump_add_page()/dump_drop_page().
  605          *
  606          * However, i386 still needs this workspace internally within the
  607          * minidump code.  In theory, they are not needed on i386, but are
  608          * included should the sf_buf code decide to use them.
  609          */
  610         last_pa = 0;
  611         vm_page_dump_pages = 0;
  612         for (i = 0; dump_avail[i + 1] != 0; i += 2) {
  613                 vm_page_dump_pages += howmany(dump_avail[i + 1], PAGE_SIZE) -
  614                     dump_avail[i] / PAGE_SIZE;
  615                 if (dump_avail[i + 1] > last_pa)
  616                         last_pa = dump_avail[i + 1];
  617         }
  618         vm_page_dump_size = round_page(BITSET_SIZE(vm_page_dump_pages));
  619         new_end -= vm_page_dump_size;
  620         vm_page_dump = (void *)(uintptr_t)pmap_map(&vaddr, new_end,
  621             new_end + vm_page_dump_size, VM_PROT_READ | VM_PROT_WRITE);
  622         bzero((void *)vm_page_dump, vm_page_dump_size);
  623 #else
  624         (void)last_pa;
  625 #endif
  626 #if defined(__aarch64__) || defined(__amd64__) || defined(__mips__) || \
  627     defined(__riscv) || defined(__powerpc64__)
  628         /*
  629          * Include the UMA bootstrap pages, witness pages and vm_page_dump
  630          * in a crash dump.  When pmap_map() uses the direct map, they are
  631          * not automatically included.
  632          */
  633         for (pa = new_end; pa < end; pa += PAGE_SIZE)
  634                 dump_add_page(pa);
  635 #endif
  636         phys_avail[biggestone + 1] = new_end;
  637 #ifdef __amd64__
  638         /*
  639          * Request that the physical pages underlying the message buffer be
  640          * included in a crash dump.  Since the message buffer is accessed
  641          * through the direct map, they are not automatically included.
  642          */
  643         pa = DMAP_TO_PHYS((vm_offset_t)msgbufp->msg_ptr);
  644         last_pa = pa + round_page(msgbufsize);
  645         while (pa < last_pa) {
  646                 dump_add_page(pa);
  647                 pa += PAGE_SIZE;
  648         }
  649 #endif
  650         /*
  651          * Compute the number of pages of memory that will be available for
  652          * use, taking into account the overhead of a page structure per page.
  653          * In other words, solve
  654          *      "available physical memory" - round_page(page_range *
  655          *          sizeof(struct vm_page)) = page_range * PAGE_SIZE 
  656          * for page_range.  
  657          */
  658         low_avail = phys_avail[0];
  659         high_avail = phys_avail[1];
  660         for (i = 0; i < vm_phys_nsegs; i++) {
  661                 if (vm_phys_segs[i].start < low_avail)
  662                         low_avail = vm_phys_segs[i].start;
  663                 if (vm_phys_segs[i].end > high_avail)
  664                         high_avail = vm_phys_segs[i].end;
  665         }
  666         /* Skip the first chunk.  It is already accounted for. */
  667         for (i = 2; phys_avail[i + 1] != 0; i += 2) {
  668                 if (phys_avail[i] < low_avail)
  669                         low_avail = phys_avail[i];
  670                 if (phys_avail[i + 1] > high_avail)
  671                         high_avail = phys_avail[i + 1];
  672         }
  673         first_page = low_avail / PAGE_SIZE;
  674 #ifdef VM_PHYSSEG_SPARSE
  675         size = 0;
  676         for (i = 0; i < vm_phys_nsegs; i++)
  677                 size += vm_phys_segs[i].end - vm_phys_segs[i].start;
  678         for (i = 0; phys_avail[i + 1] != 0; i += 2)
  679                 size += phys_avail[i + 1] - phys_avail[i];
  680 #elif defined(VM_PHYSSEG_DENSE)
  681         size = high_avail - low_avail;
  682 #else
  683 #error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined."
  684 #endif
  685 
  686 #ifdef PMAP_HAS_PAGE_ARRAY
  687         pmap_page_array_startup(size / PAGE_SIZE);
  688         biggestone = vm_phys_avail_largest();
  689         end = new_end = phys_avail[biggestone + 1];
  690 #else
  691 #ifdef VM_PHYSSEG_DENSE
  692         /*
  693          * In the VM_PHYSSEG_DENSE case, the number of pages can account for
  694          * the overhead of a page structure per page only if vm_page_array is
  695          * allocated from the last physical memory chunk.  Otherwise, we must
  696          * allocate page structures representing the physical memory
  697          * underlying vm_page_array, even though they will not be used.
  698          */
  699         if (new_end != high_avail)
  700                 page_range = size / PAGE_SIZE;
  701         else
  702 #endif
  703         {
  704                 page_range = size / (PAGE_SIZE + sizeof(struct vm_page));
  705 
  706                 /*
  707                  * If the partial bytes remaining are large enough for
  708                  * a page (PAGE_SIZE) without a corresponding
  709                  * 'struct vm_page', then new_end will contain an
  710                  * extra page after subtracting the length of the VM
  711                  * page array.  Compensate by subtracting an extra
  712                  * page from new_end.
  713                  */
  714                 if (size % (PAGE_SIZE + sizeof(struct vm_page)) >= PAGE_SIZE) {
  715                         if (new_end == high_avail)
  716                                 high_avail -= PAGE_SIZE;
  717                         new_end -= PAGE_SIZE;
  718                 }
  719         }
  720         end = new_end;
  721         new_end = vm_page_array_alloc(&vaddr, end, page_range);
  722 #endif
  723 
  724 #if VM_NRESERVLEVEL > 0
  725         /*
  726          * Allocate physical memory for the reservation management system's
  727          * data structures, and map it.
  728          */
  729         new_end = vm_reserv_startup(&vaddr, new_end);
  730 #endif
  731 #if defined(__aarch64__) || defined(__amd64__) || defined(__mips__) || \
  732     defined(__riscv) || defined(__powerpc64__)
  733         /*
  734          * Include vm_page_array and vm_reserv_array in a crash dump.
  735          */
  736         for (pa = new_end; pa < end; pa += PAGE_SIZE)
  737                 dump_add_page(pa);
  738 #endif
  739         phys_avail[biggestone + 1] = new_end;
  740 
  741         /*
  742          * Add physical memory segments corresponding to the available
  743          * physical pages.
  744          */
  745         for (i = 0; phys_avail[i + 1] != 0; i += 2)
  746                 if (vm_phys_avail_size(i) != 0)
  747                         vm_phys_add_seg(phys_avail[i], phys_avail[i + 1]);
  748 
  749         /*
  750          * Initialize the physical memory allocator.
  751          */
  752         vm_phys_init();
  753 
  754         /*
  755          * Initialize the page structures and add every available page to the
  756          * physical memory allocator's free lists.
  757          */
  758 #if defined(__i386__) && defined(VM_PHYSSEG_DENSE)
  759         for (ii = 0; ii < vm_page_array_size; ii++) {
  760                 m = &vm_page_array[ii];
  761                 vm_page_init_page(m, (first_page + ii) << PAGE_SHIFT, 0);
  762                 m->flags = PG_FICTITIOUS;
  763         }
  764 #endif
  765         vm_cnt.v_page_count = 0;
  766         for (segind = 0; segind < vm_phys_nsegs; segind++) {
  767                 seg = &vm_phys_segs[segind];
  768                 for (m = seg->first_page, pa = seg->start; pa < seg->end;
  769                     m++, pa += PAGE_SIZE)
  770                         vm_page_init_page(m, pa, segind);
  771 
  772                 /*
  773                  * Add the segment to the free lists only if it is covered by
  774                  * one of the ranges in phys_avail.  Because we've added the
  775                  * ranges to the vm_phys_segs array, we can assume that each
  776                  * segment is either entirely contained in one of the ranges,
  777                  * or doesn't overlap any of them.
  778                  */
  779                 for (i = 0; phys_avail[i + 1] != 0; i += 2) {
  780                         struct vm_domain *vmd;
  781 
  782                         if (seg->start < phys_avail[i] ||
  783                             seg->end > phys_avail[i + 1])
  784                                 continue;
  785 
  786                         m = seg->first_page;
  787                         pagecount = (u_long)atop(seg->end - seg->start);
  788 
  789                         vmd = VM_DOMAIN(seg->domain);
  790                         vm_domain_free_lock(vmd);
  791                         vm_phys_enqueue_contig(m, pagecount);
  792                         vm_domain_free_unlock(vmd);
  793                         vm_domain_freecnt_inc(vmd, pagecount);
  794                         vm_cnt.v_page_count += (u_int)pagecount;
  795 
  796                         vmd = VM_DOMAIN(seg->domain);
  797                         vmd->vmd_page_count += (u_int)pagecount;
  798                         vmd->vmd_segs |= 1UL << m->segind;
  799                         break;
  800                 }
  801         }
  802 
  803         /*
  804          * Remove blacklisted pages from the physical memory allocator.
  805          */
  806         TAILQ_INIT(&blacklist_head);
  807         vm_page_blacklist_load(&list, &listend);
  808         vm_page_blacklist_check(list, listend);
  809 
  810         list = kern_getenv("vm.blacklist");
  811         vm_page_blacklist_check(list, NULL);
  812 
  813         freeenv(list);
  814 #if VM_NRESERVLEVEL > 0
  815         /*
  816          * Initialize the reservation management system.
  817          */
  818         vm_reserv_init();
  819 #endif
  820 
  821         return (vaddr);
  822 }
  823 
  824 void
  825 vm_page_reference(vm_page_t m)
  826 {
  827 
  828         vm_page_aflag_set(m, PGA_REFERENCED);
  829 }
  830 
  831 /*
  832  *      vm_page_trybusy
  833  *
  834  *      Helper routine for grab functions to trylock busy.
  835  *
  836  *      Returns true on success and false on failure.
  837  */
  838 static bool
  839 vm_page_trybusy(vm_page_t m, int allocflags)
  840 {
  841 
  842         if ((allocflags & (VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY)) != 0)
  843                 return (vm_page_trysbusy(m));
  844         else
  845                 return (vm_page_tryxbusy(m));
  846 }
  847 
  848 /*
  849  *      vm_page_tryacquire
  850  *
  851  *      Helper routine for grab functions to trylock busy and wire.
  852  *
  853  *      Returns true on success and false on failure.
  854  */
  855 static inline bool
  856 vm_page_tryacquire(vm_page_t m, int allocflags)
  857 {
  858         bool locked;
  859 
  860         locked = vm_page_trybusy(m, allocflags);
  861         if (locked && (allocflags & VM_ALLOC_WIRED) != 0)
  862                 vm_page_wire(m);
  863         return (locked);
  864 }
  865 
  866 /*
  867  *      vm_page_busy_acquire:
  868  *
  869  *      Acquire the busy lock as described by VM_ALLOC_* flags.  Will loop
  870  *      and drop the object lock if necessary.
  871  */
  872 bool
  873 vm_page_busy_acquire(vm_page_t m, int allocflags)
  874 {
  875         vm_object_t obj;
  876         bool locked;
  877 
  878         /*
  879          * The page-specific object must be cached because page
  880          * identity can change during the sleep, causing the
  881          * re-lock of a different object.
  882          * It is assumed that a reference to the object is already
  883          * held by the callers.
  884          */
  885         obj = atomic_load_ptr(&m->object);
  886         for (;;) {
  887                 if (vm_page_tryacquire(m, allocflags))
  888                         return (true);
  889                 if ((allocflags & VM_ALLOC_NOWAIT) != 0)
  890                         return (false);
  891                 if (obj != NULL)
  892                         locked = VM_OBJECT_WOWNED(obj);
  893                 else
  894                         locked = false;
  895                 MPASS(locked || vm_page_wired(m));
  896                 if (_vm_page_busy_sleep(obj, m, m->pindex, "vmpba", allocflags,
  897                     locked) && locked)
  898                         VM_OBJECT_WLOCK(obj);
  899                 if ((allocflags & VM_ALLOC_WAITFAIL) != 0)
  900                         return (false);
  901                 KASSERT(m->object == obj || m->object == NULL,
  902                     ("vm_page_busy_acquire: page %p does not belong to %p",
  903                     m, obj));
  904         }
  905 }
  906 
  907 /*
  908  *      vm_page_busy_downgrade:
  909  *
  910  *      Downgrade an exclusive busy page into a single shared busy page.
  911  */
  912 void
  913 vm_page_busy_downgrade(vm_page_t m)
  914 {
  915         u_int x;
  916 
  917         vm_page_assert_xbusied(m);
  918 
  919         x = vm_page_busy_fetch(m);
  920         for (;;) {
  921                 if (atomic_fcmpset_rel_int(&m->busy_lock,
  922                     &x, VPB_SHARERS_WORD(1)))
  923                         break;
  924         }
  925         if ((x & VPB_BIT_WAITERS) != 0)
  926                 wakeup(m);
  927 }
  928 
  929 /*
  930  *
  931  *      vm_page_busy_tryupgrade:
  932  *
  933  *      Attempt to upgrade a single shared busy into an exclusive busy.
  934  */
  935 int
  936 vm_page_busy_tryupgrade(vm_page_t m)
  937 {
  938         u_int ce, x;
  939 
  940         vm_page_assert_sbusied(m);
  941 
  942         x = vm_page_busy_fetch(m);
  943         ce = VPB_CURTHREAD_EXCLUSIVE;
  944         for (;;) {
  945                 if (VPB_SHARERS(x) > 1)
  946                         return (0);
  947                 KASSERT((x & ~VPB_BIT_WAITERS) == VPB_SHARERS_WORD(1),
  948                     ("vm_page_busy_tryupgrade: invalid lock state"));
  949                 if (!atomic_fcmpset_acq_int(&m->busy_lock, &x,
  950                     ce | (x & VPB_BIT_WAITERS)))
  951                         continue;
  952                 return (1);
  953         }
  954 }
  955 
  956 /*
  957  *      vm_page_sbusied:
  958  *
  959  *      Return a positive value if the page is shared busied, 0 otherwise.
  960  */
  961 int
  962 vm_page_sbusied(vm_page_t m)
  963 {
  964         u_int x;
  965 
  966         x = vm_page_busy_fetch(m);
  967         return ((x & VPB_BIT_SHARED) != 0 && x != VPB_UNBUSIED);
  968 }
  969 
  970 /*
  971  *      vm_page_sunbusy:
  972  *
  973  *      Shared unbusy a page.
  974  */
  975 void
  976 vm_page_sunbusy(vm_page_t m)
  977 {
  978         u_int x;
  979 
  980         vm_page_assert_sbusied(m);
  981 
  982         x = vm_page_busy_fetch(m);
  983         for (;;) {
  984                 KASSERT(x != VPB_FREED,
  985                     ("vm_page_sunbusy: Unlocking freed page."));
  986                 if (VPB_SHARERS(x) > 1) {
  987                         if (atomic_fcmpset_int(&m->busy_lock, &x,
  988                             x - VPB_ONE_SHARER))
  989                                 break;
  990                         continue;
  991                 }
  992                 KASSERT((x & ~VPB_BIT_WAITERS) == VPB_SHARERS_WORD(1),
  993                     ("vm_page_sunbusy: invalid lock state"));
  994                 if (!atomic_fcmpset_rel_int(&m->busy_lock, &x, VPB_UNBUSIED))
  995                         continue;
  996                 if ((x & VPB_BIT_WAITERS) == 0)
  997                         break;
  998                 wakeup(m);
  999                 break;
 1000         }
 1001 }
 1002 
 1003 /*
 1004  *      vm_page_busy_sleep:
 1005  *
 1006  *      Sleep if the page is busy, using the page pointer as wchan.
 1007  *      This is used to implement the hard-path of busying mechanism.
 1008  *
 1009  *      If nonshared is true, sleep only if the page is xbusy.
 1010  *
 1011  *      The object lock must be held on entry and will be released on exit.
 1012  */
 1013 void
 1014 vm_page_busy_sleep(vm_page_t m, const char *wmesg, bool nonshared)
 1015 {
 1016         vm_object_t obj;
 1017 
 1018         obj = m->object;
 1019         VM_OBJECT_ASSERT_LOCKED(obj);
 1020         vm_page_lock_assert(m, MA_NOTOWNED);
 1021 
 1022         if (!_vm_page_busy_sleep(obj, m, m->pindex, wmesg,
 1023             nonshared ? VM_ALLOC_SBUSY : 0 , true))
 1024                 VM_OBJECT_DROP(obj);
 1025 }
 1026 
 1027 /*
 1028  *      vm_page_busy_sleep_unlocked:
 1029  *
 1030  *      Sleep if the page is busy, using the page pointer as wchan.
 1031  *      This is used to implement the hard-path of busying mechanism.
 1032  *
 1033  *      If nonshared is true, sleep only if the page is xbusy.
 1034  *
 1035  *      The object lock must not be held on entry.  The operation will
 1036  *      return if the page changes identity.
 1037  */
 1038 void
 1039 vm_page_busy_sleep_unlocked(vm_object_t obj, vm_page_t m, vm_pindex_t pindex,
 1040     const char *wmesg, bool nonshared)
 1041 {
 1042 
 1043         VM_OBJECT_ASSERT_UNLOCKED(obj);
 1044         vm_page_lock_assert(m, MA_NOTOWNED);
 1045 
 1046         _vm_page_busy_sleep(obj, m, pindex, wmesg,
 1047             nonshared ? VM_ALLOC_SBUSY : 0, false);
 1048 }
 1049 
 1050 /*
 1051  *      _vm_page_busy_sleep:
 1052  *
 1053  *      Internal busy sleep function.  Verifies the page identity and
 1054  *      lockstate against parameters.  Returns true if it sleeps and
 1055  *      false otherwise.
 1056  *
 1057  *      If locked is true the lock will be dropped for any true returns
 1058  *      and held for any false returns.
 1059  */
 1060 static bool
 1061 _vm_page_busy_sleep(vm_object_t obj, vm_page_t m, vm_pindex_t pindex,
 1062     const char *wmesg, int allocflags, bool locked)
 1063 {
 1064         bool xsleep;
 1065         u_int x;
 1066 
 1067         /*
 1068          * If the object is busy we must wait for that to drain to zero
 1069          * before trying the page again.
 1070          */
 1071         if (obj != NULL && vm_object_busied(obj)) {
 1072                 if (locked)
 1073                         VM_OBJECT_DROP(obj);
 1074                 vm_object_busy_wait(obj, wmesg);
 1075                 return (true);
 1076         }
 1077 
 1078         if (!vm_page_busied(m))
 1079                 return (false);
 1080 
 1081         xsleep = (allocflags & (VM_ALLOC_SBUSY | VM_ALLOC_IGN_SBUSY)) != 0;
 1082         sleepq_lock(m);
 1083         x = vm_page_busy_fetch(m);
 1084         do {
 1085                 /*
 1086                  * If the page changes objects or becomes unlocked we can
 1087                  * simply return.
 1088                  */
 1089                 if (x == VPB_UNBUSIED ||
 1090                     (xsleep && (x & VPB_BIT_SHARED) != 0) ||
 1091                     m->object != obj || m->pindex != pindex) {
 1092                         sleepq_release(m);
 1093                         return (false);
 1094                 }
 1095                 if ((x & VPB_BIT_WAITERS) != 0)
 1096                         break;
 1097         } while (!atomic_fcmpset_int(&m->busy_lock, &x, x | VPB_BIT_WAITERS));
 1098         if (locked)
 1099                 VM_OBJECT_DROP(obj);
 1100         DROP_GIANT();
 1101         sleepq_add(m, NULL, wmesg, 0, 0);
 1102         sleepq_wait(m, PVM);
 1103         PICKUP_GIANT();
 1104         return (true);
 1105 }
 1106 
 1107 /*
 1108  *      vm_page_trysbusy:
 1109  *
 1110  *      Try to shared busy a page.
 1111  *      If the operation succeeds 1 is returned otherwise 0.
 1112  *      The operation never sleeps.
 1113  */
 1114 int
 1115 vm_page_trysbusy(vm_page_t m)
 1116 {
 1117         vm_object_t obj;
 1118         u_int x;
 1119 
 1120         obj = m->object;
 1121         x = vm_page_busy_fetch(m);
 1122         for (;;) {
 1123                 if ((x & VPB_BIT_SHARED) == 0)
 1124                         return (0);
 1125                 /*
 1126                  * Reduce the window for transient busies that will trigger
 1127                  * false negatives in vm_page_ps_test().
 1128                  */
 1129                 if (obj != NULL && vm_object_busied(obj))
 1130                         return (0);
 1131                 if (atomic_fcmpset_acq_int(&m->busy_lock, &x,
 1132                     x + VPB_ONE_SHARER))
 1133                         break;
 1134         }
 1135 
 1136         /* Refetch the object now that we're guaranteed that it is stable. */
 1137         obj = m->object;
 1138         if (obj != NULL && vm_object_busied(obj)) {
 1139                 vm_page_sunbusy(m);
 1140                 return (0);
 1141         }
 1142         return (1);
 1143 }
 1144 
 1145 /*
 1146  *      vm_page_tryxbusy:
 1147  *
 1148  *      Try to exclusive busy a page.
 1149  *      If the operation succeeds 1 is returned otherwise 0.
 1150  *      The operation never sleeps.
 1151  */
 1152 int
 1153 vm_page_tryxbusy(vm_page_t m)
 1154 {
 1155         vm_object_t obj;
 1156 
 1157         if (atomic_cmpset_acq_int(&m->busy_lock, VPB_UNBUSIED,
 1158             VPB_CURTHREAD_EXCLUSIVE) == 0)
 1159                 return (0);
 1160 
 1161         obj = m->object;
 1162         if (obj != NULL && vm_object_busied(obj)) {
 1163                 vm_page_xunbusy(m);
 1164                 return (0);
 1165         }
 1166         return (1);
 1167 }
 1168 
 1169 static void
 1170 vm_page_xunbusy_hard_tail(vm_page_t m)
 1171 {
 1172         atomic_store_rel_int(&m->busy_lock, VPB_UNBUSIED);
 1173         /* Wake the waiter. */
 1174         wakeup(m);
 1175 }
 1176 
 1177 /*
 1178  *      vm_page_xunbusy_hard:
 1179  *
 1180  *      Called when unbusy has failed because there is a waiter.
 1181  */
 1182 void
 1183 vm_page_xunbusy_hard(vm_page_t m)
 1184 {
 1185         vm_page_assert_xbusied(m);
 1186         vm_page_xunbusy_hard_tail(m);
 1187 }
 1188 
 1189 void
 1190 vm_page_xunbusy_hard_unchecked(vm_page_t m)
 1191 {
 1192         vm_page_assert_xbusied_unchecked(m);
 1193         vm_page_xunbusy_hard_tail(m);
 1194 }
 1195 
 1196 static void
 1197 vm_page_busy_free(vm_page_t m)
 1198 {
 1199         u_int x;
 1200 
 1201         atomic_thread_fence_rel();
 1202         x = atomic_swap_int(&m->busy_lock, VPB_FREED);
 1203         if ((x & VPB_BIT_WAITERS) != 0)
 1204                 wakeup(m);
 1205 }
 1206 
 1207 /*
 1208  *      vm_page_unhold_pages:
 1209  *
 1210  *      Unhold each of the pages that is referenced by the given array.
 1211  */
 1212 void
 1213 vm_page_unhold_pages(vm_page_t *ma, int count)
 1214 {
 1215 
 1216         for (; count != 0; count--) {
 1217                 vm_page_unwire(*ma, PQ_ACTIVE);
 1218                 ma++;
 1219         }
 1220 }
 1221 
 1222 vm_page_t
 1223 PHYS_TO_VM_PAGE(vm_paddr_t pa)
 1224 {
 1225         vm_page_t m;
 1226 
 1227 #ifdef VM_PHYSSEG_SPARSE
 1228         m = vm_phys_paddr_to_vm_page(pa);
 1229         if (m == NULL)
 1230                 m = vm_phys_fictitious_to_vm_page(pa);
 1231         return (m);
 1232 #elif defined(VM_PHYSSEG_DENSE)
 1233         long pi;
 1234 
 1235         pi = atop(pa);
 1236         if (pi >= first_page && (pi - first_page) < vm_page_array_size) {
 1237                 m = &vm_page_array[pi - first_page];
 1238                 return (m);
 1239         }
 1240         return (vm_phys_fictitious_to_vm_page(pa));
 1241 #else
 1242 #error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined."
 1243 #endif
 1244 }
 1245 
 1246 /*
 1247  *      vm_page_getfake:
 1248  *
 1249  *      Create a fictitious page with the specified physical address and
 1250  *      memory attribute.  The memory attribute is the only the machine-
 1251  *      dependent aspect of a fictitious page that must be initialized.
 1252  */
 1253 vm_page_t
 1254 vm_page_getfake(vm_paddr_t paddr, vm_memattr_t memattr)
 1255 {
 1256         vm_page_t m;
 1257 
 1258         m = uma_zalloc(fakepg_zone, M_WAITOK | M_ZERO);
 1259         vm_page_initfake(m, paddr, memattr);
 1260         return (m);
 1261 }
 1262 
 1263 void
 1264 vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr)
 1265 {
 1266 
 1267         if ((m->flags & PG_FICTITIOUS) != 0) {
 1268                 /*
 1269                  * The page's memattr might have changed since the
 1270                  * previous initialization.  Update the pmap to the
 1271                  * new memattr.
 1272                  */
 1273                 goto memattr;
 1274         }
 1275         m->phys_addr = paddr;
 1276         m->a.queue = PQ_NONE;
 1277         /* Fictitious pages don't use "segind". */
 1278         m->flags = PG_FICTITIOUS;
 1279         /* Fictitious pages don't use "order" or "pool". */
 1280         m->oflags = VPO_UNMANAGED;
 1281         m->busy_lock = VPB_CURTHREAD_EXCLUSIVE;
 1282         /* Fictitious pages are unevictable. */
 1283         m->ref_count = 1;
 1284         pmap_page_init(m);
 1285 memattr:
 1286         pmap_page_set_memattr(m, memattr);
 1287 }
 1288 
 1289 /*
 1290  *      vm_page_putfake:
 1291  *
 1292  *      Release a fictitious page.
 1293  */
 1294 void
 1295 vm_page_putfake(vm_page_t m)
 1296 {
 1297 
 1298         KASSERT((m->oflags & VPO_UNMANAGED) != 0, ("managed %p", m));
 1299         KASSERT((m->flags & PG_FICTITIOUS) != 0,
 1300             ("vm_page_putfake: bad page %p", m));
 1301         vm_page_assert_xbusied(m);
 1302         vm_page_busy_free(m);
 1303         uma_zfree(fakepg_zone, m);
 1304 }
 1305 
 1306 /*
 1307  *      vm_page_updatefake:
 1308  *
 1309  *      Update the given fictitious page to the specified physical address and
 1310  *      memory attribute.
 1311  */
 1312 void
 1313 vm_page_updatefake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr)
 1314 {
 1315 
 1316         KASSERT((m->flags & PG_FICTITIOUS) != 0,
 1317             ("vm_page_updatefake: bad page %p", m));
 1318         m->phys_addr = paddr;
 1319         pmap_page_set_memattr(m, memattr);
 1320 }
 1321 
 1322 /*
 1323  *      vm_page_free:
 1324  *
 1325  *      Free a page.
 1326  */
 1327 void
 1328 vm_page_free(vm_page_t m)
 1329 {
 1330 
 1331         m->flags &= ~PG_ZERO;
 1332         vm_page_free_toq(m);
 1333 }
 1334 
 1335 /*
 1336  *      vm_page_free_zero:
 1337  *
 1338  *      Free a page to the zerod-pages queue
 1339  */
 1340 void
 1341 vm_page_free_zero(vm_page_t m)
 1342 {
 1343 
 1344         m->flags |= PG_ZERO;
 1345         vm_page_free_toq(m);
 1346 }
 1347 
 1348 /*
 1349  * Unbusy and handle the page queueing for a page from a getpages request that
 1350  * was optionally read ahead or behind.
 1351  */
 1352 void
 1353 vm_page_readahead_finish(vm_page_t m)
 1354 {
 1355 
 1356         /* We shouldn't put invalid pages on queues. */
 1357         KASSERT(!vm_page_none_valid(m), ("%s: %p is invalid", __func__, m));
 1358 
 1359         /*
 1360          * Since the page is not the actually needed one, whether it should
 1361          * be activated or deactivated is not obvious.  Empirical results
 1362          * have shown that deactivating the page is usually the best choice,
 1363          * unless the page is wanted by another thread.
 1364          */
 1365         if ((vm_page_busy_fetch(m) & VPB_BIT_WAITERS) != 0)
 1366                 vm_page_activate(m);
 1367         else
 1368                 vm_page_deactivate(m);
 1369         vm_page_xunbusy_unchecked(m);
 1370 }
 1371 
 1372 /*
 1373  * Destroy the identity of an invalid page and free it if possible.
 1374  * This is intended to be used when reading a page from backing store fails.
 1375  */
 1376 void
 1377 vm_page_free_invalid(vm_page_t m)
 1378 {
 1379 
 1380         KASSERT(vm_page_none_valid(m), ("page %p is valid", m));
 1381         KASSERT(!pmap_page_is_mapped(m), ("page %p is mapped", m));
 1382         KASSERT(m->object != NULL, ("page %p has no object", m));
 1383         VM_OBJECT_ASSERT_WLOCKED(m->object);
 1384 
 1385         /*
 1386          * We may be attempting to free the page as part of the handling for an
 1387          * I/O error, in which case the page was xbusied by a different thread.
 1388          */
 1389         vm_page_xbusy_claim(m);
 1390 
 1391         /*
 1392          * If someone has wired this page while the object lock
 1393          * was not held, then the thread that unwires is responsible
 1394          * for freeing the page.  Otherwise just free the page now.
 1395          * The wire count of this unmapped page cannot change while
 1396          * we have the page xbusy and the page's object wlocked.
 1397          */
 1398         if (vm_page_remove(m))
 1399                 vm_page_free(m);
 1400 }
 1401 
 1402 /*
 1403  *      vm_page_sleep_if_busy:
 1404  *
 1405  *      Sleep and release the object lock if the page is busied.
 1406  *      Returns TRUE if the thread slept.
 1407  *
 1408  *      The given page must be unlocked and object containing it must
 1409  *      be locked.
 1410  */
 1411 int
 1412 vm_page_sleep_if_busy(vm_page_t m, const char *wmesg)
 1413 {
 1414         vm_object_t obj;
 1415 
 1416         vm_page_lock_assert(m, MA_NOTOWNED);
 1417         VM_OBJECT_ASSERT_WLOCKED(m->object);
 1418 
 1419         /*
 1420          * The page-specific object must be cached because page
 1421          * identity can change during the sleep, causing the
 1422          * re-lock of a different object.
 1423          * It is assumed that a reference to the object is already
 1424          * held by the callers.
 1425          */
 1426         obj = m->object;
 1427         if (_vm_page_busy_sleep(obj, m, m->pindex, wmesg, 0, true)) {
 1428                 VM_OBJECT_WLOCK(obj);
 1429                 return (TRUE);
 1430         }
 1431         return (FALSE);
 1432 }
 1433 
 1434 /*
 1435  *      vm_page_sleep_if_xbusy:
 1436  *
 1437  *      Sleep and release the object lock if the page is xbusied.
 1438  *      Returns TRUE if the thread slept.
 1439  *
 1440  *      The given page must be unlocked and object containing it must
 1441  *      be locked.
 1442  */
 1443 int
 1444 vm_page_sleep_if_xbusy(vm_page_t m, const char *wmesg)
 1445 {
 1446         vm_object_t obj;
 1447 
 1448         vm_page_lock_assert(m, MA_NOTOWNED);
 1449         VM_OBJECT_ASSERT_WLOCKED(m->object);
 1450 
 1451         /*
 1452          * The page-specific object must be cached because page
 1453          * identity can change during the sleep, causing the
 1454          * re-lock of a different object.
 1455          * It is assumed that a reference to the object is already
 1456          * held by the callers.
 1457          */
 1458         obj = m->object;
 1459         if (_vm_page_busy_sleep(obj, m, m->pindex, wmesg, VM_ALLOC_SBUSY,
 1460             true)) {
 1461                 VM_OBJECT_WLOCK(obj);
 1462                 return (TRUE);
 1463         }
 1464         return (FALSE);
 1465 }
 1466 
 1467 /*
 1468  *      vm_page_dirty_KBI:              [ internal use only ]
 1469  *
 1470  *      Set all bits in the page's dirty field.
 1471  *
 1472  *      The object containing the specified page must be locked if the
 1473  *      call is made from the machine-independent layer.
 1474  *
 1475  *      See vm_page_clear_dirty_mask().
 1476  *
 1477  *      This function should only be called by vm_page_dirty().
 1478  */
 1479 void
 1480 vm_page_dirty_KBI(vm_page_t m)
 1481 {
 1482 
 1483         /* Refer to this operation by its public name. */
 1484         KASSERT(vm_page_all_valid(m), ("vm_page_dirty: page is invalid!"));
 1485         m->dirty = VM_PAGE_BITS_ALL;
 1486 }
 1487 
 1488 /*
 1489  *      vm_page_insert:         [ internal use only ]
 1490  *
 1491  *      Inserts the given mem entry into the object and object list.
 1492  *
 1493  *      The object must be locked.
 1494  */
 1495 int
 1496 vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex)
 1497 {
 1498         vm_page_t mpred;
 1499 
 1500         VM_OBJECT_ASSERT_WLOCKED(object);
 1501         mpred = vm_radix_lookup_le(&object->rtree, pindex);
 1502         return (vm_page_insert_after(m, object, pindex, mpred));
 1503 }
 1504 
 1505 /*
 1506  *      vm_page_insert_after:
 1507  *
 1508  *      Inserts the page "m" into the specified object at offset "pindex".
 1509  *
 1510  *      The page "mpred" must immediately precede the offset "pindex" within
 1511  *      the specified object.
 1512  *
 1513  *      The object must be locked.
 1514  */
 1515 static int
 1516 vm_page_insert_after(vm_page_t m, vm_object_t object, vm_pindex_t pindex,
 1517     vm_page_t mpred)
 1518 {
 1519         vm_page_t msucc;
 1520 
 1521         VM_OBJECT_ASSERT_WLOCKED(object);
 1522         KASSERT(m->object == NULL,
 1523             ("vm_page_insert_after: page already inserted"));
 1524         if (mpred != NULL) {
 1525                 KASSERT(mpred->object == object,
 1526                     ("vm_page_insert_after: object doesn't contain mpred"));
 1527                 KASSERT(mpred->pindex < pindex,
 1528                     ("vm_page_insert_after: mpred doesn't precede pindex"));
 1529                 msucc = TAILQ_NEXT(mpred, listq);
 1530         } else
 1531                 msucc = TAILQ_FIRST(&object->memq);
 1532         if (msucc != NULL)
 1533                 KASSERT(msucc->pindex > pindex,
 1534                     ("vm_page_insert_after: msucc doesn't succeed pindex"));
 1535 
 1536         /*
 1537          * Record the object/offset pair in this page.
 1538          */
 1539         m->object = object;
 1540         m->pindex = pindex;
 1541         m->ref_count |= VPRC_OBJREF;
 1542 
 1543         /*
 1544          * Now link into the object's ordered list of backed pages.
 1545          */
 1546         if (vm_radix_insert(&object->rtree, m)) {
 1547                 m->object = NULL;
 1548                 m->pindex = 0;
 1549                 m->ref_count &= ~VPRC_OBJREF;
 1550                 return (1);
 1551         }
 1552         vm_page_insert_radixdone(m, object, mpred);
 1553         return (0);
 1554 }
 1555 
 1556 /*
 1557  *      vm_page_insert_radixdone:
 1558  *
 1559  *      Complete page "m" insertion into the specified object after the
 1560  *      radix trie hooking.
 1561  *
 1562  *      The page "mpred" must precede the offset "m->pindex" within the
 1563  *      specified object.
 1564  *
 1565  *      The object must be locked.
 1566  */
 1567 static void
 1568 vm_page_insert_radixdone(vm_page_t m, vm_object_t object, vm_page_t mpred)
 1569 {
 1570 
 1571         VM_OBJECT_ASSERT_WLOCKED(object);
 1572         KASSERT(object != NULL && m->object == object,
 1573             ("vm_page_insert_radixdone: page %p has inconsistent object", m));
 1574         KASSERT((m->ref_count & VPRC_OBJREF) != 0,
 1575             ("vm_page_insert_radixdone: page %p is missing object ref", m));
 1576         if (mpred != NULL) {
 1577                 KASSERT(mpred->object == object,
 1578                     ("vm_page_insert_radixdone: object doesn't contain mpred"));
 1579                 KASSERT(mpred->pindex < m->pindex,
 1580                     ("vm_page_insert_radixdone: mpred doesn't precede pindex"));
 1581         }
 1582 
 1583         if (mpred != NULL)
 1584                 TAILQ_INSERT_AFTER(&object->memq, mpred, m, listq);
 1585         else
 1586                 TAILQ_INSERT_HEAD(&object->memq, m, listq);
 1587 
 1588         /*
 1589          * Show that the object has one more resident page.
 1590          */
 1591         object->resident_page_count++;
 1592 
 1593         /*
 1594          * Hold the vnode until the last page is released.
 1595          */
 1596         if (object->resident_page_count == 1 && object->type == OBJT_VNODE)
 1597                 vhold(object->handle);
 1598 
 1599         /*
 1600          * Since we are inserting a new and possibly dirty page,
 1601          * update the object's generation count.
 1602          */
 1603         if (pmap_page_is_write_mapped(m))
 1604                 vm_object_set_writeable_dirty(object);
 1605 }
 1606 
 1607 /*
 1608  * Do the work to remove a page from its object.  The caller is responsible for
 1609  * updating the page's fields to reflect this removal.
 1610  */
 1611 static void
 1612 vm_page_object_remove(vm_page_t m)
 1613 {
 1614         vm_object_t object;
 1615         vm_page_t mrem;
 1616 
 1617         vm_page_assert_xbusied(m);
 1618         object = m->object;
 1619         VM_OBJECT_ASSERT_WLOCKED(object);
 1620         KASSERT((m->ref_count & VPRC_OBJREF) != 0,
 1621             ("page %p is missing its object ref", m));
 1622 
 1623         /* Deferred free of swap space. */
 1624         if ((m->a.flags & PGA_SWAP_FREE) != 0)
 1625                 vm_pager_page_unswapped(m);
 1626 
 1627         m->object = NULL;
 1628         mrem = vm_radix_remove(&object->rtree, m->pindex);
 1629         KASSERT(mrem == m, ("removed page %p, expected page %p", mrem, m));
 1630 
 1631         /*
 1632          * Now remove from the object's list of backed pages.
 1633          */
 1634         TAILQ_REMOVE(&object->memq, m, listq);
 1635 
 1636         /*
 1637          * And show that the object has one fewer resident page.
 1638          */
 1639         object->resident_page_count--;
 1640 
 1641         /*
 1642          * The vnode may now be recycled.
 1643          */
 1644         if (object->resident_page_count == 0 && object->type == OBJT_VNODE)
 1645                 vdrop(object->handle);
 1646 }
 1647 
 1648 /*
 1649  *      vm_page_remove:
 1650  *
 1651  *      Removes the specified page from its containing object, but does not
 1652  *      invalidate any backing storage.  Returns true if the object's reference
 1653  *      was the last reference to the page, and false otherwise.
 1654  *
 1655  *      The object must be locked and the page must be exclusively busied.
 1656  *      The exclusive busy will be released on return.  If this is not the
 1657  *      final ref and the caller does not hold a wire reference it may not
 1658  *      continue to access the page.
 1659  */
 1660 bool
 1661 vm_page_remove(vm_page_t m)
 1662 {
 1663         bool dropped;
 1664 
 1665         dropped = vm_page_remove_xbusy(m);
 1666         vm_page_xunbusy(m);
 1667 
 1668         return (dropped);
 1669 }
 1670 
 1671 /*
 1672  *      vm_page_remove_xbusy
 1673  *
 1674  *      Removes the page but leaves the xbusy held.  Returns true if this
 1675  *      removed the final ref and false otherwise.
 1676  */
 1677 bool
 1678 vm_page_remove_xbusy(vm_page_t m)
 1679 {
 1680 
 1681         vm_page_object_remove(m);
 1682         return (vm_page_drop(m, VPRC_OBJREF) == VPRC_OBJREF);
 1683 }
 1684 
 1685 /*
 1686  *      vm_page_lookup:
 1687  *
 1688  *      Returns the page associated with the object/offset
 1689  *      pair specified; if none is found, NULL is returned.
 1690  *
 1691  *      The object must be locked.
 1692  */
 1693 vm_page_t
 1694 vm_page_lookup(vm_object_t object, vm_pindex_t pindex)
 1695 {
 1696 
 1697         VM_OBJECT_ASSERT_LOCKED(object);
 1698         return (vm_radix_lookup(&object->rtree, pindex));
 1699 }
 1700 
 1701 /*
 1702  *      vm_page_lookup_unlocked:
 1703  *
 1704  *      Returns the page associated with the object/offset pair specified;
 1705  *      if none is found, NULL is returned.  The page may be no longer be
 1706  *      present in the object at the time that this function returns.  Only
 1707  *      useful for opportunistic checks such as inmem().
 1708  */
 1709 vm_page_t
 1710 vm_page_lookup_unlocked(vm_object_t object, vm_pindex_t pindex)
 1711 {
 1712 
 1713         return (vm_radix_lookup_unlocked(&object->rtree, pindex));
 1714 }
 1715 
 1716 /*
 1717  *      vm_page_relookup:
 1718  *
 1719  *      Returns a page that must already have been busied by
 1720  *      the caller.  Used for bogus page replacement.
 1721  */
 1722 vm_page_t
 1723 vm_page_relookup(vm_object_t object, vm_pindex_t pindex)
 1724 {
 1725         vm_page_t m;
 1726 
 1727         m = vm_radix_lookup_unlocked(&object->rtree, pindex);
 1728         KASSERT(m != NULL && (vm_page_busied(m) || vm_page_wired(m)) &&
 1729             m->object == object && m->pindex == pindex,
 1730             ("vm_page_relookup: Invalid page %p", m));
 1731         return (m);
 1732 }
 1733 
 1734 /*
 1735  * This should only be used by lockless functions for releasing transient
 1736  * incorrect acquires.  The page may have been freed after we acquired a
 1737  * busy lock.  In this case busy_lock == VPB_FREED and we have nothing
 1738  * further to do.
 1739  */
 1740 static void
 1741 vm_page_busy_release(vm_page_t m)
 1742 {
 1743         u_int x;
 1744 
 1745         x = vm_page_busy_fetch(m);
 1746         for (;;) {
 1747                 if (x == VPB_FREED)
 1748                         break;
 1749                 if ((x & VPB_BIT_SHARED) != 0 && VPB_SHARERS(x) > 1) {
 1750                         if (atomic_fcmpset_int(&m->busy_lock, &x,
 1751                             x - VPB_ONE_SHARER))
 1752                                 break;
 1753                         continue;
 1754                 }
 1755                 KASSERT((x & VPB_BIT_SHARED) != 0 ||
 1756                     (x & ~VPB_BIT_WAITERS) == VPB_CURTHREAD_EXCLUSIVE,
 1757                     ("vm_page_busy_release: %p xbusy not owned.", m));
 1758                 if (!atomic_fcmpset_rel_int(&m->busy_lock, &x, VPB_UNBUSIED))
 1759                         continue;
 1760                 if ((x & VPB_BIT_WAITERS) != 0)
 1761                         wakeup(m);
 1762                 break;
 1763         }
 1764 }
 1765 
 1766 /*
 1767  *      vm_page_find_least:
 1768  *
 1769  *      Returns the page associated with the object with least pindex
 1770  *      greater than or equal to the parameter pindex, or NULL.
 1771  *
 1772  *      The object must be locked.
 1773  */
 1774 vm_page_t
 1775 vm_page_find_least(vm_object_t object, vm_pindex_t pindex)
 1776 {
 1777         vm_page_t m;
 1778 
 1779         VM_OBJECT_ASSERT_LOCKED(object);
 1780         if ((m = TAILQ_FIRST(&object->memq)) != NULL && m->pindex < pindex)
 1781                 m = vm_radix_lookup_ge(&object->rtree, pindex);
 1782         return (m);
 1783 }
 1784 
 1785 /*
 1786  * Returns the given page's successor (by pindex) within the object if it is
 1787  * resident; if none is found, NULL is returned.
 1788  *
 1789  * The object must be locked.
 1790  */
 1791 vm_page_t
 1792 vm_page_next(vm_page_t m)
 1793 {
 1794         vm_page_t next;
 1795 
 1796         VM_OBJECT_ASSERT_LOCKED(m->object);
 1797         if ((next = TAILQ_NEXT(m, listq)) != NULL) {
 1798                 MPASS(next->object == m->object);
 1799                 if (next->pindex != m->pindex + 1)
 1800                         next = NULL;
 1801         }
 1802         return (next);
 1803 }
 1804 
 1805 /*
 1806  * Returns the given page's predecessor (by pindex) within the object if it is
 1807  * resident; if none is found, NULL is returned.
 1808  *
 1809  * The object must be locked.
 1810  */
 1811 vm_page_t
 1812 vm_page_prev(vm_page_t m)
 1813 {
 1814         vm_page_t prev;
 1815 
 1816         VM_OBJECT_ASSERT_LOCKED(m->object);
 1817         if ((prev = TAILQ_PREV(m, pglist, listq)) != NULL) {
 1818                 MPASS(prev->object == m->object);
 1819                 if (prev->pindex != m->pindex - 1)
 1820                         prev = NULL;
 1821         }
 1822         return (prev);
 1823 }
 1824 
 1825 /*
 1826  * Uses the page mnew as a replacement for an existing page at index
 1827  * pindex which must be already present in the object.
 1828  *
 1829  * Both pages must be exclusively busied on enter.  The old page is
 1830  * unbusied on exit.
 1831  *
 1832  * A return value of true means mold is now free.  If this is not the
 1833  * final ref and the caller does not hold a wire reference it may not
 1834  * continue to access the page.
 1835  */
 1836 static bool
 1837 vm_page_replace_hold(vm_page_t mnew, vm_object_t object, vm_pindex_t pindex,
 1838     vm_page_t mold)
 1839 {
 1840         vm_page_t mret;
 1841         bool dropped;
 1842 
 1843         VM_OBJECT_ASSERT_WLOCKED(object);
 1844         vm_page_assert_xbusied(mold);
 1845         KASSERT(mnew->object == NULL && (mnew->ref_count & VPRC_OBJREF) == 0,
 1846             ("vm_page_replace: page %p already in object", mnew));
 1847 
 1848         /*
 1849          * This function mostly follows vm_page_insert() and
 1850          * vm_page_remove() without the radix, object count and vnode
 1851          * dance.  Double check such functions for more comments.
 1852          */
 1853 
 1854         mnew->object = object;
 1855         mnew->pindex = pindex;
 1856         atomic_set_int(&mnew->ref_count, VPRC_OBJREF);
 1857         mret = vm_radix_replace(&object->rtree, mnew);
 1858         KASSERT(mret == mold,
 1859             ("invalid page replacement, mold=%p, mret=%p", mold, mret));
 1860         KASSERT((mold->oflags & VPO_UNMANAGED) ==
 1861             (mnew->oflags & VPO_UNMANAGED),
 1862             ("vm_page_replace: mismatched VPO_UNMANAGED"));
 1863 
 1864         /* Keep the resident page list in sorted order. */
 1865         TAILQ_INSERT_AFTER(&object->memq, mold, mnew, listq);
 1866         TAILQ_REMOVE(&object->memq, mold, listq);
 1867         mold->object = NULL;
 1868 
 1869         /*
 1870          * The object's resident_page_count does not change because we have
 1871          * swapped one page for another, but the generation count should
 1872          * change if the page is dirty.
 1873          */
 1874         if (pmap_page_is_write_mapped(mnew))
 1875                 vm_object_set_writeable_dirty(object);
 1876         dropped = vm_page_drop(mold, VPRC_OBJREF) == VPRC_OBJREF;
 1877         vm_page_xunbusy(mold);
 1878 
 1879         return (dropped);
 1880 }
 1881 
 1882 void
 1883 vm_page_replace(vm_page_t mnew, vm_object_t object, vm_pindex_t pindex,
 1884     vm_page_t mold)
 1885 {
 1886 
 1887         vm_page_assert_xbusied(mnew);
 1888 
 1889         if (vm_page_replace_hold(mnew, object, pindex, mold))
 1890                 vm_page_free(mold);
 1891 }
 1892 
 1893 /*
 1894  *      vm_page_rename:
 1895  *
 1896  *      Move the given memory entry from its
 1897  *      current object to the specified target object/offset.
 1898  *
 1899  *      Note: swap associated with the page must be invalidated by the move.  We
 1900  *            have to do this for several reasons:  (1) we aren't freeing the
 1901  *            page, (2) we are dirtying the page, (3) the VM system is probably
 1902  *            moving the page from object A to B, and will then later move
 1903  *            the backing store from A to B and we can't have a conflict.
 1904  *
 1905  *      Note: we *always* dirty the page.  It is necessary both for the
 1906  *            fact that we moved it, and because we may be invalidating
 1907  *            swap.
 1908  *
 1909  *      The objects must be locked.
 1910  */
 1911 int
 1912 vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex)
 1913 {
 1914         vm_page_t mpred;
 1915         vm_pindex_t opidx;
 1916 
 1917         VM_OBJECT_ASSERT_WLOCKED(new_object);
 1918 
 1919         KASSERT(m->ref_count != 0, ("vm_page_rename: page %p has no refs", m));
 1920         mpred = vm_radix_lookup_le(&new_object->rtree, new_pindex);
 1921         KASSERT(mpred == NULL || mpred->pindex != new_pindex,
 1922             ("vm_page_rename: pindex already renamed"));
 1923 
 1924         /*
 1925          * Create a custom version of vm_page_insert() which does not depend
 1926          * by m_prev and can cheat on the implementation aspects of the
 1927          * function.
 1928          */
 1929         opidx = m->pindex;
 1930         m->pindex = new_pindex;
 1931         if (vm_radix_insert(&new_object->rtree, m)) {
 1932                 m->pindex = opidx;
 1933                 return (1);
 1934         }
 1935 
 1936         /*
 1937          * The operation cannot fail anymore.  The removal must happen before
 1938          * the listq iterator is tainted.
 1939          */
 1940         m->pindex = opidx;
 1941         vm_page_object_remove(m);
 1942 
 1943         /* Return back to the new pindex to complete vm_page_insert(). */
 1944         m->pindex = new_pindex;
 1945         m->object = new_object;
 1946 
 1947         vm_page_insert_radixdone(m, new_object, mpred);
 1948         vm_page_dirty(m);
 1949         return (0);
 1950 }
 1951 
 1952 /*
 1953  *      vm_page_alloc:
 1954  *
 1955  *      Allocate and return a page that is associated with the specified
 1956  *      object and offset pair.  By default, this page is exclusive busied.
 1957  *
 1958  *      The caller must always specify an allocation class.
 1959  *
 1960  *      allocation classes:
 1961  *      VM_ALLOC_NORMAL         normal process request
 1962  *      VM_ALLOC_SYSTEM         system *really* needs a page
 1963  *      VM_ALLOC_INTERRUPT      interrupt time request
 1964  *
 1965  *      optional allocation flags:
 1966  *      VM_ALLOC_COUNT(number)  the number of additional pages that the caller
 1967  *                              intends to allocate
 1968  *      VM_ALLOC_NOBUSY         do not exclusive busy the page
 1969  *      VM_ALLOC_NODUMP         do not include the page in a kernel core dump
 1970  *      VM_ALLOC_NOOBJ          page is not associated with an object and
 1971  *                              should not be exclusive busy
 1972  *      VM_ALLOC_SBUSY          shared busy the allocated page
 1973  *      VM_ALLOC_WIRED          wire the allocated page
 1974  *      VM_ALLOC_ZERO           prefer a zeroed page
 1975  */
 1976 vm_page_t
 1977 vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req)
 1978 {
 1979 
 1980         return (vm_page_alloc_after(object, pindex, req, object != NULL ?
 1981             vm_radix_lookup_le(&object->rtree, pindex) : NULL));
 1982 }
 1983 
 1984 vm_page_t
 1985 vm_page_alloc_domain(vm_object_t object, vm_pindex_t pindex, int domain,
 1986     int req)
 1987 {
 1988 
 1989         return (vm_page_alloc_domain_after(object, pindex, domain, req,
 1990             object != NULL ? vm_radix_lookup_le(&object->rtree, pindex) :
 1991             NULL));
 1992 }
 1993 
 1994 /*
 1995  * Allocate a page in the specified object with the given page index.  To
 1996  * optimize insertion of the page into the object, the caller must also specifiy
 1997  * the resident page in the object with largest index smaller than the given
 1998  * page index, or NULL if no such page exists.
 1999  */
 2000 vm_page_t
 2001 vm_page_alloc_after(vm_object_t object, vm_pindex_t pindex,
 2002     int req, vm_page_t mpred)
 2003 {
 2004         struct vm_domainset_iter di;
 2005         vm_page_t m;
 2006         int domain;
 2007 
 2008         vm_domainset_iter_page_init(&di, object, pindex, &domain, &req);
 2009         do {
 2010                 m = vm_page_alloc_domain_after(object, pindex, domain, req,
 2011                     mpred);
 2012                 if (m != NULL)
 2013                         break;
 2014         } while (vm_domainset_iter_page(&di, object, &domain) == 0);
 2015 
 2016         return (m);
 2017 }
 2018 
 2019 /*
 2020  * Returns true if the number of free pages exceeds the minimum
 2021  * for the request class and false otherwise.
 2022  */
 2023 static int
 2024 _vm_domain_allocate(struct vm_domain *vmd, int req_class, int npages)
 2025 {
 2026         u_int limit, old, new;
 2027 
 2028         if (req_class == VM_ALLOC_INTERRUPT)
 2029                 limit = 0;
 2030         else if (req_class == VM_ALLOC_SYSTEM)
 2031                 limit = vmd->vmd_interrupt_free_min;
 2032         else
 2033                 limit = vmd->vmd_free_reserved;
 2034 
 2035         /*
 2036          * Attempt to reserve the pages.  Fail if we're below the limit.
 2037          */
 2038         limit += npages;
 2039         old = vmd->vmd_free_count;
 2040         do {
 2041                 if (old < limit)
 2042                         return (0);
 2043                 new = old - npages;
 2044         } while (atomic_fcmpset_int(&vmd->vmd_free_count, &old, new) == 0);
 2045 
 2046         /* Wake the page daemon if we've crossed the threshold. */
 2047         if (vm_paging_needed(vmd, new) && !vm_paging_needed(vmd, old))
 2048                 pagedaemon_wakeup(vmd->vmd_domain);
 2049 
 2050         /* Only update bitsets on transitions. */
 2051         if ((old >= vmd->vmd_free_min && new < vmd->vmd_free_min) ||
 2052             (old >= vmd->vmd_free_severe && new < vmd->vmd_free_severe))
 2053                 vm_domain_set(vmd);
 2054 
 2055         return (1);
 2056 }
 2057 
 2058 int
 2059 vm_domain_allocate(struct vm_domain *vmd, int req, int npages)
 2060 {
 2061         int req_class;
 2062 
 2063         /*
 2064          * The page daemon is allowed to dig deeper into the free page list.
 2065          */
 2066         req_class = req & VM_ALLOC_CLASS_MASK;
 2067         if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT)
 2068                 req_class = VM_ALLOC_SYSTEM;
 2069         return (_vm_domain_allocate(vmd, req_class, npages));
 2070 }
 2071 
 2072 vm_page_t
 2073 vm_page_alloc_domain_after(vm_object_t object, vm_pindex_t pindex, int domain,
 2074     int req, vm_page_t mpred)
 2075 {
 2076         struct vm_domain *vmd;
 2077         vm_page_t m;
 2078         int flags, pool;
 2079 
 2080         KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0) &&
 2081             (object != NULL || (req & VM_ALLOC_SBUSY) == 0) &&
 2082             ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) !=
 2083             (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)),
 2084             ("inconsistent object(%p)/req(%x)", object, req));
 2085         KASSERT(object == NULL || (req & VM_ALLOC_WAITOK) == 0,
 2086             ("Can't sleep and retry object insertion."));
 2087         KASSERT(mpred == NULL || mpred->pindex < pindex,
 2088             ("mpred %p doesn't precede pindex 0x%jx", mpred,
 2089             (uintmax_t)pindex));
 2090         if (object != NULL)
 2091                 VM_OBJECT_ASSERT_WLOCKED(object);
 2092 
 2093         flags = 0;
 2094         m = NULL;
 2095         pool = object != NULL ? VM_FREEPOOL_DEFAULT : VM_FREEPOOL_DIRECT;
 2096 again:
 2097 #if VM_NRESERVLEVEL > 0
 2098         /*
 2099          * Can we allocate the page from a reservation?
 2100          */
 2101         if (vm_object_reserv(object) &&
 2102             (m = vm_reserv_alloc_page(object, pindex, domain, req, mpred)) !=
 2103             NULL) {
 2104                 goto found;
 2105         }
 2106 #endif
 2107         vmd = VM_DOMAIN(domain);
 2108         if (vmd->vmd_pgcache[pool].zone != NULL) {
 2109                 m = uma_zalloc(vmd->vmd_pgcache[pool].zone, M_NOWAIT | M_NOVM);
 2110                 if (m != NULL) {
 2111                         flags |= PG_PCPU_CACHE;
 2112                         goto found;
 2113                 }
 2114         }
 2115         if (vm_domain_allocate(vmd, req, 1)) {
 2116                 /*
 2117                  * If not, allocate it from the free page queues.
 2118                  */
 2119                 vm_domain_free_lock(vmd);
 2120                 m = vm_phys_alloc_pages(domain, pool, 0);
 2121                 vm_domain_free_unlock(vmd);
 2122                 if (m == NULL) {
 2123                         vm_domain_freecnt_inc(vmd, 1);
 2124 #if VM_NRESERVLEVEL > 0
 2125                         if (vm_reserv_reclaim_inactive(domain))
 2126                                 goto again;
 2127 #endif
 2128                 }
 2129         }
 2130         if (m == NULL) {
 2131                 /*
 2132                  * Not allocatable, give up.
 2133                  */
 2134                 if (vm_domain_alloc_fail(vmd, object, req))
 2135                         goto again;
 2136                 return (NULL);
 2137         }
 2138 
 2139         /*
 2140          * At this point we had better have found a good page.
 2141          */
 2142 found:
 2143         vm_page_dequeue(m);
 2144         vm_page_alloc_check(m);
 2145 
 2146         /*
 2147          * Initialize the page.  Only the PG_ZERO flag is inherited.
 2148          */
 2149         if ((req & VM_ALLOC_ZERO) != 0)
 2150                 flags |= (m->flags & PG_ZERO);
 2151         if ((req & VM_ALLOC_NODUMP) != 0)
 2152                 flags |= PG_NODUMP;
 2153         m->flags = flags;
 2154         m->a.flags = 0;
 2155         m->oflags = object == NULL || (object->flags & OBJ_UNMANAGED) != 0 ?
 2156             VPO_UNMANAGED : 0;
 2157         if ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ | VM_ALLOC_SBUSY)) == 0)
 2158                 m->busy_lock = VPB_CURTHREAD_EXCLUSIVE;
 2159         else if ((req & VM_ALLOC_SBUSY) != 0)
 2160                 m->busy_lock = VPB_SHARERS_WORD(1);
 2161         else
 2162                 m->busy_lock = VPB_UNBUSIED;
 2163         if (req & VM_ALLOC_WIRED) {
 2164                 vm_wire_add(1);
 2165                 m->ref_count = 1;
 2166         }
 2167         m->a.act_count = 0;
 2168 
 2169         if (object != NULL) {
 2170                 if (vm_page_insert_after(m, object, pindex, mpred)) {
 2171                         if (req & VM_ALLOC_WIRED) {
 2172                                 vm_wire_sub(1);
 2173                                 m->ref_count = 0;
 2174                         }
 2175                         KASSERT(m->object == NULL, ("page %p has object", m));
 2176                         m->oflags = VPO_UNMANAGED;
 2177                         m->busy_lock = VPB_UNBUSIED;
 2178                         /* Don't change PG_ZERO. */
 2179                         vm_page_free_toq(m);
 2180                         if (req & VM_ALLOC_WAITFAIL) {
 2181                                 VM_OBJECT_WUNLOCK(object);
 2182                                 vm_radix_wait();
 2183                                 VM_OBJECT_WLOCK(object);
 2184                         }
 2185                         return (NULL);
 2186                 }
 2187 
 2188                 /* Ignore device objects; the pager sets "memattr" for them. */
 2189                 if (object->memattr != VM_MEMATTR_DEFAULT &&
 2190                     (object->flags & OBJ_FICTITIOUS) == 0)
 2191                         pmap_page_set_memattr(m, object->memattr);
 2192         } else
 2193                 m->pindex = pindex;
 2194 
 2195         return (m);
 2196 }
 2197 
 2198 /*
 2199  *      vm_page_alloc_contig:
 2200  *
 2201  *      Allocate a contiguous set of physical pages of the given size "npages"
 2202  *      from the free lists.  All of the physical pages must be at or above
 2203  *      the given physical address "low" and below the given physical address
 2204  *      "high".  The given value "alignment" determines the alignment of the
 2205  *      first physical page in the set.  If the given value "boundary" is
 2206  *      non-zero, then the set of physical pages cannot cross any physical
 2207  *      address boundary that is a multiple of that value.  Both "alignment"
 2208  *      and "boundary" must be a power of two.
 2209  *
 2210  *      If the specified memory attribute, "memattr", is VM_MEMATTR_DEFAULT,
 2211  *      then the memory attribute setting for the physical pages is configured
 2212  *      to the object's memory attribute setting.  Otherwise, the memory
 2213  *      attribute setting for the physical pages is configured to "memattr",
 2214  *      overriding the object's memory attribute setting.  However, if the
 2215  *      object's memory attribute setting is not VM_MEMATTR_DEFAULT, then the
 2216  *      memory attribute setting for the physical pages cannot be configured
 2217  *      to VM_MEMATTR_DEFAULT.
 2218  *
 2219  *      The specified object may not contain fictitious pages.
 2220  *
 2221  *      The caller must always specify an allocation class.
 2222  *
 2223  *      allocation classes:
 2224  *      VM_ALLOC_NORMAL         normal process request
 2225  *      VM_ALLOC_SYSTEM         system *really* needs a page
 2226  *      VM_ALLOC_INTERRUPT      interrupt time request
 2227  *
 2228  *      optional allocation flags:
 2229  *      VM_ALLOC_NOBUSY         do not exclusive busy the page
 2230  *      VM_ALLOC_NODUMP         do not include the page in a kernel core dump
 2231  *      VM_ALLOC_NOOBJ          page is not associated with an object and
 2232  *                              should not be exclusive busy
 2233  *      VM_ALLOC_SBUSY          shared busy the allocated page
 2234  *      VM_ALLOC_WIRED          wire the allocated page
 2235  *      VM_ALLOC_ZERO           prefer a zeroed page
 2236  */
 2237 vm_page_t
 2238 vm_page_alloc_contig(vm_object_t object, vm_pindex_t pindex, int req,
 2239     u_long npages, vm_paddr_t low, vm_paddr_t high, u_long alignment,
 2240     vm_paddr_t boundary, vm_memattr_t memattr)
 2241 {
 2242         struct vm_domainset_iter di;
 2243         vm_page_t m;
 2244         int domain;
 2245 
 2246         vm_domainset_iter_page_init(&di, object, pindex, &domain, &req);
 2247         do {
 2248                 m = vm_page_alloc_contig_domain(object, pindex, domain, req,
 2249                     npages, low, high, alignment, boundary, memattr);
 2250                 if (m != NULL)
 2251                         break;
 2252         } while (vm_domainset_iter_page(&di, object, &domain) == 0);
 2253 
 2254         return (m);
 2255 }
 2256 
 2257 vm_page_t
 2258 vm_page_alloc_contig_domain(vm_object_t object, vm_pindex_t pindex, int domain,
 2259     int req, u_long npages, vm_paddr_t low, vm_paddr_t high, u_long alignment,
 2260     vm_paddr_t boundary, vm_memattr_t memattr)
 2261 {
 2262         struct vm_domain *vmd;
 2263         vm_page_t m, m_ret, mpred;
 2264         u_int busy_lock, flags, oflags;
 2265 
 2266         mpred = NULL;   /* XXX: pacify gcc */
 2267         KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0) &&
 2268             (object != NULL || (req & VM_ALLOC_SBUSY) == 0) &&
 2269             ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)) !=
 2270             (VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY)),
 2271             ("vm_page_alloc_contig: inconsistent object(%p)/req(%x)", object,
 2272             req));
 2273         KASSERT(object == NULL || (req & VM_ALLOC_WAITOK) == 0,
 2274             ("Can't sleep and retry object insertion."));
 2275         if (object != NULL) {
 2276                 VM_OBJECT_ASSERT_WLOCKED(object);
 2277                 KASSERT((object->flags & OBJ_FICTITIOUS) == 0,
 2278                     ("vm_page_alloc_contig: object %p has fictitious pages",
 2279                     object));
 2280         }
 2281         KASSERT(npages > 0, ("vm_page_alloc_contig: npages is zero"));
 2282 
 2283         if (object != NULL) {
 2284                 mpred = vm_radix_lookup_le(&object->rtree, pindex);
 2285                 KASSERT(mpred == NULL || mpred->pindex != pindex,
 2286                     ("vm_page_alloc_contig: pindex already allocated"));
 2287         }
 2288 
 2289         /*
 2290          * Can we allocate the pages without the number of free pages falling
 2291          * below the lower bound for the allocation class?
 2292          */
 2293         m_ret = NULL;
 2294 again:
 2295 #if VM_NRESERVLEVEL > 0
 2296         /*
 2297          * Can we allocate the pages from a reservation?
 2298          */
 2299         if (vm_object_reserv(object) &&
 2300             (m_ret = vm_reserv_alloc_contig(object, pindex, domain, req,
 2301             mpred, npages, low, high, alignment, boundary)) != NULL) {
 2302                 goto found;
 2303         }
 2304 #endif
 2305         vmd = VM_DOMAIN(domain);
 2306         if (vm_domain_allocate(vmd, req, npages)) {
 2307                 /*
 2308                  * allocate them from the free page queues.
 2309                  */
 2310                 vm_domain_free_lock(vmd);
 2311                 m_ret = vm_phys_alloc_contig(domain, npages, low, high,
 2312                     alignment, boundary);
 2313                 vm_domain_free_unlock(vmd);
 2314                 if (m_ret == NULL) {
 2315                         vm_domain_freecnt_inc(vmd, npages);
 2316 #if VM_NRESERVLEVEL > 0
 2317                         if (vm_reserv_reclaim_contig(domain, npages, low,
 2318                             high, alignment, boundary))
 2319                                 goto again;
 2320 #endif
 2321                 }
 2322         }
 2323         if (m_ret == NULL) {
 2324                 if (vm_domain_alloc_fail(vmd, object, req))
 2325                         goto again;
 2326                 return (NULL);
 2327         }
 2328 #if VM_NRESERVLEVEL > 0
 2329 found:
 2330 #endif
 2331         for (m = m_ret; m < &m_ret[npages]; m++) {
 2332                 vm_page_dequeue(m);
 2333                 vm_page_alloc_check(m);
 2334         }
 2335 
 2336         /*
 2337          * Initialize the pages.  Only the PG_ZERO flag is inherited.
 2338          */
 2339         flags = 0;
 2340         if ((req & VM_ALLOC_ZERO) != 0)
 2341                 flags = PG_ZERO;
 2342         if ((req & VM_ALLOC_NODUMP) != 0)
 2343                 flags |= PG_NODUMP;
 2344         oflags = object == NULL || (object->flags & OBJ_UNMANAGED) != 0 ?
 2345             VPO_UNMANAGED : 0;
 2346         if ((req & (VM_ALLOC_NOBUSY | VM_ALLOC_NOOBJ | VM_ALLOC_SBUSY)) == 0)
 2347                 busy_lock = VPB_CURTHREAD_EXCLUSIVE;
 2348         else if ((req & VM_ALLOC_SBUSY) != 0)
 2349                 busy_lock = VPB_SHARERS_WORD(1);
 2350         else
 2351                 busy_lock = VPB_UNBUSIED;
 2352         if ((req & VM_ALLOC_WIRED) != 0)
 2353                 vm_wire_add(npages);
 2354         if (object != NULL) {
 2355                 if (object->memattr != VM_MEMATTR_DEFAULT &&
 2356                     memattr == VM_MEMATTR_DEFAULT)
 2357                         memattr = object->memattr;
 2358         }
 2359         for (m = m_ret; m < &m_ret[npages]; m++) {
 2360                 m->a.flags = 0;
 2361                 m->flags = (m->flags | PG_NODUMP) & flags;
 2362                 m->busy_lock = busy_lock;
 2363                 if ((req & VM_ALLOC_WIRED) != 0)
 2364                         m->ref_count = 1;
 2365                 m->a.act_count = 0;
 2366                 m->oflags = oflags;
 2367                 if (object != NULL) {
 2368                         if (vm_page_insert_after(m, object, pindex, mpred)) {
 2369                                 if ((req & VM_ALLOC_WIRED) != 0)
 2370                                         vm_wire_sub(npages);
 2371                                 KASSERT(m->object == NULL,
 2372                                     ("page %p has object", m));
 2373                                 mpred = m;
 2374                                 for (m = m_ret; m < &m_ret[npages]; m++) {
 2375                                         if (m <= mpred &&
 2376                                             (req & VM_ALLOC_WIRED) != 0)
 2377                                                 m->ref_count = 0;
 2378                                         m->oflags = VPO_UNMANAGED;
 2379                                         m->busy_lock = VPB_UNBUSIED;
 2380                                         /* Don't change PG_ZERO. */
 2381                                         vm_page_free_toq(m);
 2382                                 }
 2383                                 if (req & VM_ALLOC_WAITFAIL) {
 2384                                         VM_OBJECT_WUNLOCK(object);
 2385                                         vm_radix_wait();
 2386                                         VM_OBJECT_WLOCK(object);
 2387                                 }
 2388                                 return (NULL);
 2389                         }
 2390                         mpred = m;
 2391                 } else
 2392                         m->pindex = pindex;
 2393                 if (memattr != VM_MEMATTR_DEFAULT)
 2394                         pmap_page_set_memattr(m, memattr);
 2395                 pindex++;
 2396         }
 2397         return (m_ret);
 2398 }
 2399 
 2400 /*
 2401  * Check a page that has been freshly dequeued from a freelist.
 2402  */
 2403 static void
 2404 vm_page_alloc_check(vm_page_t m)
 2405 {
 2406 
 2407         KASSERT(m->object == NULL, ("page %p has object", m));
 2408         KASSERT(m->a.queue == PQ_NONE &&
 2409             (m->a.flags & PGA_QUEUE_STATE_MASK) == 0,
 2410             ("page %p has unexpected queue %d, flags %#x",
 2411             m, m->a.queue, (m->a.flags & PGA_QUEUE_STATE_MASK)));
 2412         KASSERT(m->ref_count == 0, ("page %p has references", m));
 2413         KASSERT(vm_page_busy_freed(m), ("page %p is not freed", m));
 2414         KASSERT(m->dirty == 0, ("page %p is dirty", m));
 2415         KASSERT(pmap_page_get_memattr(m) == VM_MEMATTR_DEFAULT,
 2416             ("page %p has unexpected memattr %d",
 2417             m, pmap_page_get_memattr(m)));
 2418         KASSERT(m->valid == 0, ("free page %p is valid", m));
 2419 }
 2420 
 2421 /*
 2422  *      vm_page_alloc_freelist:
 2423  *
 2424  *      Allocate a physical page from the specified free page list.
 2425  *
 2426  *      The caller must always specify an allocation class.
 2427  *
 2428  *      allocation classes:
 2429  *      VM_ALLOC_NORMAL         normal process request
 2430  *      VM_ALLOC_SYSTEM         system *really* needs a page
 2431  *      VM_ALLOC_INTERRUPT      interrupt time request
 2432  *
 2433  *      optional allocation flags:
 2434  *      VM_ALLOC_COUNT(number)  the number of additional pages that the caller
 2435  *                              intends to allocate
 2436  *      VM_ALLOC_WIRED          wire the allocated page
 2437  *      VM_ALLOC_ZERO           prefer a zeroed page
 2438  */
 2439 vm_page_t
 2440 vm_page_alloc_freelist(int freelist, int req)
 2441 {
 2442         struct vm_domainset_iter di;
 2443         vm_page_t m;
 2444         int domain;
 2445 
 2446         vm_domainset_iter_page_init(&di, NULL, 0, &domain, &req);
 2447         do {
 2448                 m = vm_page_alloc_freelist_domain(domain, freelist, req);
 2449                 if (m != NULL)
 2450                         break;
 2451         } while (vm_domainset_iter_page(&di, NULL, &domain) == 0);
 2452 
 2453         return (m);
 2454 }
 2455 
 2456 vm_page_t
 2457 vm_page_alloc_freelist_domain(int domain, int freelist, int req)
 2458 {
 2459         struct vm_domain *vmd;
 2460         vm_page_t m;
 2461         u_int flags;
 2462 
 2463         m = NULL;
 2464         vmd = VM_DOMAIN(domain);
 2465 again:
 2466         if (vm_domain_allocate(vmd, req, 1)) {
 2467                 vm_domain_free_lock(vmd);
 2468                 m = vm_phys_alloc_freelist_pages(domain, freelist,
 2469                     VM_FREEPOOL_DIRECT, 0);
 2470                 vm_domain_free_unlock(vmd);
 2471                 if (m == NULL)
 2472                         vm_domain_freecnt_inc(vmd, 1);
 2473         }
 2474         if (m == NULL) {
 2475                 if (vm_domain_alloc_fail(vmd, NULL, req))
 2476                         goto again;
 2477                 return (NULL);
 2478         }
 2479         vm_page_dequeue(m);
 2480         vm_page_alloc_check(m);
 2481 
 2482         /*
 2483          * Initialize the page.  Only the PG_ZERO flag is inherited.
 2484          */
 2485         m->a.flags = 0;
 2486         flags = 0;
 2487         if ((req & VM_ALLOC_ZERO) != 0)
 2488                 flags = PG_ZERO;
 2489         m->flags &= flags;
 2490         if ((req & VM_ALLOC_WIRED) != 0) {
 2491                 vm_wire_add(1);
 2492                 m->ref_count = 1;
 2493         }
 2494         /* Unmanaged pages don't use "act_count". */
 2495         m->oflags = VPO_UNMANAGED;
 2496         return (m);
 2497 }
 2498 
 2499 static int
 2500 vm_page_zone_import(void *arg, void **store, int cnt, int domain, int flags)
 2501 {
 2502         struct vm_domain *vmd;
 2503         struct vm_pgcache *pgcache;
 2504         int i;
 2505 
 2506         pgcache = arg;
 2507         vmd = VM_DOMAIN(pgcache->domain);
 2508 
 2509         /*
 2510          * The page daemon should avoid creating extra memory pressure since its
 2511          * main purpose is to replenish the store of free pages.
 2512          */
 2513         if (vmd->vmd_severeset || curproc == pageproc ||
 2514             !_vm_domain_allocate(vmd, VM_ALLOC_NORMAL, cnt))
 2515                 return (0);
 2516         domain = vmd->vmd_domain;
 2517         vm_domain_free_lock(vmd);
 2518         i = vm_phys_alloc_npages(domain, pgcache->pool, cnt,
 2519             (vm_page_t *)store);
 2520         vm_domain_free_unlock(vmd);
 2521         if (cnt != i)
 2522                 vm_domain_freecnt_inc(vmd, cnt - i);
 2523 
 2524         return (i);
 2525 }
 2526 
 2527 static void
 2528 vm_page_zone_release(void *arg, void **store, int cnt)
 2529 {
 2530         struct vm_domain *vmd;
 2531         struct vm_pgcache *pgcache;
 2532         vm_page_t m;
 2533         int i;
 2534 
 2535         pgcache = arg;
 2536         vmd = VM_DOMAIN(pgcache->domain);
 2537         vm_domain_free_lock(vmd);
 2538         for (i = 0; i < cnt; i++) {
 2539                 m = (vm_page_t)store[i];
 2540                 vm_phys_free_pages(m, 0);
 2541         }
 2542         vm_domain_free_unlock(vmd);
 2543         vm_domain_freecnt_inc(vmd, cnt);
 2544 }
 2545 
 2546 #define VPSC_ANY        0       /* No restrictions. */
 2547 #define VPSC_NORESERV   1       /* Skip reservations; implies VPSC_NOSUPER. */
 2548 #define VPSC_NOSUPER    2       /* Skip superpages. */
 2549 
 2550 /*
 2551  *      vm_page_scan_contig:
 2552  *
 2553  *      Scan vm_page_array[] between the specified entries "m_start" and
 2554  *      "m_end" for a run of contiguous physical pages that satisfy the
 2555  *      specified conditions, and return the lowest page in the run.  The
 2556  *      specified "alignment" determines the alignment of the lowest physical
 2557  *      page in the run.  If the specified "boundary" is non-zero, then the
 2558  *      run of physical pages cannot span a physical address that is a
 2559  *      multiple of "boundary".
 2560  *
 2561  *      "m_end" is never dereferenced, so it need not point to a vm_page
 2562  *      structure within vm_page_array[].
 2563  *
 2564  *      "npages" must be greater than zero.  "m_start" and "m_end" must not
 2565  *      span a hole (or discontiguity) in the physical address space.  Both
 2566  *      "alignment" and "boundary" must be a power of two.
 2567  */
 2568 vm_page_t
 2569 vm_page_scan_contig(u_long npages, vm_page_t m_start, vm_page_t m_end,
 2570     u_long alignment, vm_paddr_t boundary, int options)
 2571 {
 2572         vm_object_t object;
 2573         vm_paddr_t pa;
 2574         vm_page_t m, m_run;
 2575 #if VM_NRESERVLEVEL > 0
 2576         int level;
 2577 #endif
 2578         int m_inc, order, run_ext, run_len;
 2579 
 2580         KASSERT(npages > 0, ("npages is 0"));
 2581         KASSERT(powerof2(alignment), ("alignment is not a power of 2"));
 2582         KASSERT(powerof2(boundary), ("boundary is not a power of 2"));
 2583         m_run = NULL;
 2584         run_len = 0;
 2585         for (m = m_start; m < m_end && run_len < npages; m += m_inc) {
 2586                 KASSERT((m->flags & PG_MARKER) == 0,
 2587                     ("page %p is PG_MARKER", m));
 2588                 KASSERT((m->flags & PG_FICTITIOUS) == 0 || m->ref_count >= 1,
 2589                     ("fictitious page %p has invalid ref count", m));
 2590 
 2591                 /*
 2592                  * If the current page would be the start of a run, check its
 2593                  * physical address against the end, alignment, and boundary
 2594                  * conditions.  If it doesn't satisfy these conditions, either
 2595                  * terminate the scan or advance to the next page that
 2596                  * satisfies the failed condition.
 2597                  */
 2598                 if (run_len == 0) {
 2599                         KASSERT(m_run == NULL, ("m_run != NULL"));
 2600                         if (m + npages > m_end)
 2601                                 break;
 2602                         pa = VM_PAGE_TO_PHYS(m);
 2603                         if ((pa & (alignment - 1)) != 0) {
 2604                                 m_inc = atop(roundup2(pa, alignment) - pa);
 2605                                 continue;
 2606                         }
 2607                         if (rounddown2(pa ^ (pa + ptoa(npages) - 1),
 2608                             boundary) != 0) {
 2609                                 m_inc = atop(roundup2(pa, boundary) - pa);
 2610                                 continue;
 2611                         }
 2612                 } else
 2613                         KASSERT(m_run != NULL, ("m_run == NULL"));
 2614 
 2615 retry:
 2616                 m_inc = 1;
 2617                 if (vm_page_wired(m))
 2618                         run_ext = 0;
 2619 #if VM_NRESERVLEVEL > 0
 2620                 else if ((level = vm_reserv_level(m)) >= 0 &&
 2621                     (options & VPSC_NORESERV) != 0) {
 2622                         run_ext = 0;
 2623                         /* Advance to the end of the reservation. */
 2624                         pa = VM_PAGE_TO_PHYS(m);
 2625                         m_inc = atop(roundup2(pa + 1, vm_reserv_size(level)) -
 2626                             pa);
 2627                 }
 2628 #endif
 2629                 else if ((object = atomic_load_ptr(&m->object)) != NULL) {
 2630                         /*
 2631                          * The page is considered eligible for relocation if
 2632                          * and only if it could be laundered or reclaimed by
 2633                          * the page daemon.
 2634                          */
 2635                         VM_OBJECT_RLOCK(object);
 2636                         if (object != m->object) {
 2637                                 VM_OBJECT_RUNLOCK(object);
 2638                                 goto retry;
 2639                         }
 2640                         /* Don't care: PG_NODUMP, PG_ZERO. */
 2641                         if (object->type != OBJT_DEFAULT &&
 2642                             object->type != OBJT_SWAP &&
 2643                             object->type != OBJT_VNODE) {
 2644                                 run_ext = 0;
 2645 #if VM_NRESERVLEVEL > 0
 2646                         } else if ((options & VPSC_NOSUPER) != 0 &&
 2647                             (level = vm_reserv_level_iffullpop(m)) >= 0) {
 2648                                 run_ext = 0;
 2649                                 /* Advance to the end of the superpage. */
 2650                                 pa = VM_PAGE_TO_PHYS(m);
 2651                                 m_inc = atop(roundup2(pa + 1,
 2652                                     vm_reserv_size(level)) - pa);
 2653 #endif
 2654                         } else if (object->memattr == VM_MEMATTR_DEFAULT &&
 2655                             vm_page_queue(m) != PQ_NONE && !vm_page_busied(m)) {
 2656                                 /*
 2657                                  * The page is allocated but eligible for
 2658                                  * relocation.  Extend the current run by one
 2659                                  * page.
 2660                                  */
 2661                                 KASSERT(pmap_page_get_memattr(m) ==
 2662                                     VM_MEMATTR_DEFAULT,
 2663                                     ("page %p has an unexpected memattr", m));
 2664                                 KASSERT((m->oflags & (VPO_SWAPINPROG |
 2665                                     VPO_SWAPSLEEP | VPO_UNMANAGED)) == 0,
 2666                                     ("page %p has unexpected oflags", m));
 2667                                 /* Don't care: PGA_NOSYNC. */
 2668                                 run_ext = 1;
 2669                         } else
 2670                                 run_ext = 0;
 2671                         VM_OBJECT_RUNLOCK(object);
 2672 #if VM_NRESERVLEVEL > 0
 2673                 } else if (level >= 0) {
 2674                         /*
 2675                          * The page is reserved but not yet allocated.  In
 2676                          * other words, it is still free.  Extend the current
 2677                          * run by one page.
 2678                          */
 2679                         run_ext = 1;
 2680 #endif
 2681                 } else if ((order = m->order) < VM_NFREEORDER) {
 2682                         /*
 2683                          * The page is enqueued in the physical memory
 2684                          * allocator's free page queues.  Moreover, it is the
 2685                          * first page in a power-of-two-sized run of
 2686                          * contiguous free pages.  Add these pages to the end
 2687                          * of the current run, and jump ahead.
 2688                          */
 2689                         run_ext = 1 << order;
 2690                         m_inc = 1 << order;
 2691                 } else {
 2692                         /*
 2693                          * Skip the page for one of the following reasons: (1)
 2694                          * It is enqueued in the physical memory allocator's
 2695                          * free page queues.  However, it is not the first
 2696                          * page in a run of contiguous free pages.  (This case
 2697                          * rarely occurs because the scan is performed in
 2698                          * ascending order.) (2) It is not reserved, and it is
 2699                          * transitioning from free to allocated.  (Conversely,
 2700                          * the transition from allocated to free for managed
 2701                          * pages is blocked by the page busy lock.) (3) It is
 2702                          * allocated but not contained by an object and not
 2703                          * wired, e.g., allocated by Xen's balloon driver.
 2704                          */
 2705                         run_ext = 0;
 2706                 }
 2707 
 2708                 /*
 2709                  * Extend or reset the current run of pages.
 2710                  */
 2711                 if (run_ext > 0) {
 2712                         if (run_len == 0)
 2713                                 m_run = m;
 2714                         run_len += run_ext;
 2715                 } else {
 2716                         if (run_len > 0) {
 2717                                 m_run = NULL;
 2718                                 run_len = 0;
 2719                         }
 2720                 }
 2721         }
 2722         if (run_len >= npages)
 2723                 return (m_run);
 2724         return (NULL);
 2725 }
 2726 
 2727 /*
 2728  *      vm_page_reclaim_run:
 2729  *
 2730  *      Try to relocate each of the allocated virtual pages within the
 2731  *      specified run of physical pages to a new physical address.  Free the
 2732  *      physical pages underlying the relocated virtual pages.  A virtual page
 2733  *      is relocatable if and only if it could be laundered or reclaimed by
 2734  *      the page daemon.  Whenever possible, a virtual page is relocated to a
 2735  *      physical address above "high".
 2736  *
 2737  *      Returns 0 if every physical page within the run was already free or
 2738  *      just freed by a successful relocation.  Otherwise, returns a non-zero
 2739  *      value indicating why the last attempt to relocate a virtual page was
 2740  *      unsuccessful.
 2741  *
 2742  *      "req_class" must be an allocation class.
 2743  */
 2744 static int
 2745 vm_page_reclaim_run(int req_class, int domain, u_long npages, vm_page_t m_run,
 2746     vm_paddr_t high)
 2747 {
 2748         struct vm_domain *vmd;
 2749         struct spglist free;
 2750         vm_object_t object;
 2751         vm_paddr_t pa;
 2752         vm_page_t m, m_end, m_new;
 2753         int error, order, req;
 2754 
 2755         KASSERT((req_class & VM_ALLOC_CLASS_MASK) == req_class,
 2756             ("req_class is not an allocation class"));
 2757         SLIST_INIT(&free);
 2758         error = 0;
 2759         m = m_run;
 2760         m_end = m_run + npages;
 2761         for (; error == 0 && m < m_end; m++) {
 2762                 KASSERT((m->flags & (PG_FICTITIOUS | PG_MARKER)) == 0,
 2763                     ("page %p is PG_FICTITIOUS or PG_MARKER", m));
 2764 
 2765                 /*
 2766                  * Racily check for wirings.  Races are handled once the object
 2767                  * lock is held and the page is unmapped.
 2768                  */
 2769                 if (vm_page_wired(m))
 2770                         error = EBUSY;
 2771                 else if ((object = atomic_load_ptr(&m->object)) != NULL) {
 2772                         /*
 2773                          * The page is relocated if and only if it could be
 2774                          * laundered or reclaimed by the page daemon.
 2775                          */
 2776                         VM_OBJECT_WLOCK(object);
 2777                         /* Don't care: PG_NODUMP, PG_ZERO. */
 2778                         if (m->object != object ||
 2779                             (object->type != OBJT_DEFAULT &&
 2780                             object->type != OBJT_SWAP &&
 2781                             object->type != OBJT_VNODE))
 2782                                 error = EINVAL;
 2783                         else if (object->memattr != VM_MEMATTR_DEFAULT)
 2784                                 error = EINVAL;
 2785                         else if (vm_page_queue(m) != PQ_NONE &&
 2786                             vm_page_tryxbusy(m) != 0) {
 2787                                 if (vm_page_wired(m)) {
 2788                                         vm_page_xunbusy(m);
 2789                                         error = EBUSY;
 2790                                         goto unlock;
 2791                                 }
 2792                                 KASSERT(pmap_page_get_memattr(m) ==
 2793                                     VM_MEMATTR_DEFAULT,
 2794                                     ("page %p has an unexpected memattr", m));
 2795                                 KASSERT(m->oflags == 0,
 2796                                     ("page %p has unexpected oflags", m));
 2797                                 /* Don't care: PGA_NOSYNC. */
 2798                                 if (!vm_page_none_valid(m)) {
 2799                                         /*
 2800                                          * First, try to allocate a new page
 2801                                          * that is above "high".  Failing
 2802                                          * that, try to allocate a new page
 2803                                          * that is below "m_run".  Allocate
 2804                                          * the new page between the end of
 2805                                          * "m_run" and "high" only as a last
 2806                                          * resort.
 2807                                          */
 2808                                         req = req_class | VM_ALLOC_NOOBJ;
 2809                                         if ((m->flags & PG_NODUMP) != 0)
 2810                                                 req |= VM_ALLOC_NODUMP;
 2811                                         if (trunc_page(high) !=
 2812                                             ~(vm_paddr_t)PAGE_MASK) {
 2813                                                 m_new = vm_page_alloc_contig(
 2814                                                     NULL, 0, req, 1,
 2815                                                     round_page(high),
 2816                                                     ~(vm_paddr_t)0,
 2817                                                     PAGE_SIZE, 0,
 2818                                                     VM_MEMATTR_DEFAULT);
 2819                                         } else
 2820                                                 m_new = NULL;
 2821                                         if (m_new == NULL) {
 2822                                                 pa = VM_PAGE_TO_PHYS(m_run);
 2823                                                 m_new = vm_page_alloc_contig(
 2824                                                     NULL, 0, req, 1,
 2825                                                     0, pa - 1, PAGE_SIZE, 0,
 2826                                                     VM_MEMATTR_DEFAULT);
 2827                                         }
 2828                                         if (m_new == NULL) {
 2829                                                 pa += ptoa(npages);
 2830                                                 m_new = vm_page_alloc_contig(
 2831                                                     NULL, 0, req, 1,
 2832                                                     pa, high, PAGE_SIZE, 0,
 2833                                                     VM_MEMATTR_DEFAULT);
 2834                                         }
 2835                                         if (m_new == NULL) {
 2836                                                 vm_page_xunbusy(m);
 2837                                                 error = ENOMEM;
 2838                                                 goto unlock;
 2839                                         }
 2840 
 2841                                         /*
 2842                                          * Unmap the page and check for new
 2843                                          * wirings that may have been acquired
 2844                                          * through a pmap lookup.
 2845                                          */
 2846                                         if (object->ref_count != 0 &&
 2847                                             !vm_page_try_remove_all(m)) {
 2848                                                 vm_page_xunbusy(m);
 2849                                                 vm_page_free(m_new);
 2850                                                 error = EBUSY;
 2851                                                 goto unlock;
 2852                                         }
 2853 
 2854                                         /*
 2855                                          * Replace "m" with the new page.  For
 2856                                          * vm_page_replace(), "m" must be busy
 2857                                          * and dequeued.  Finally, change "m"
 2858                                          * as if vm_page_free() was called.
 2859                                          */
 2860                                         m_new->a.flags = m->a.flags &
 2861                                             ~PGA_QUEUE_STATE_MASK;
 2862                                         KASSERT(m_new->oflags == VPO_UNMANAGED,
 2863                                             ("page %p is managed", m_new));
 2864                                         m_new->oflags = 0;
 2865                                         pmap_copy_page(m, m_new);
 2866                                         m_new->valid = m->valid;
 2867                                         m_new->dirty = m->dirty;
 2868                                         m->flags &= ~PG_ZERO;
 2869                                         vm_page_dequeue(m);
 2870                                         if (vm_page_replace_hold(m_new, object,
 2871                                             m->pindex, m) &&
 2872                                             vm_page_free_prep(m))
 2873                                                 SLIST_INSERT_HEAD(&free, m,
 2874                                                     plinks.s.ss);
 2875 
 2876                                         /*
 2877                                          * The new page must be deactivated
 2878                                          * before the object is unlocked.
 2879                                          */
 2880                                         vm_page_deactivate(m_new);
 2881                                 } else {
 2882                                         m->flags &= ~PG_ZERO;
 2883                                         vm_page_dequeue(m);
 2884                                         if (vm_page_free_prep(m))
 2885                                                 SLIST_INSERT_HEAD(&free, m,
 2886                                                     plinks.s.ss);
 2887                                         KASSERT(m->dirty == 0,
 2888                                             ("page %p is dirty", m));
 2889                                 }
 2890                         } else
 2891                                 error = EBUSY;
 2892 unlock:
 2893                         VM_OBJECT_WUNLOCK(object);
 2894                 } else {
 2895                         MPASS(vm_page_domain(m) == domain);
 2896                         vmd = VM_DOMAIN(domain);
 2897                         vm_domain_free_lock(vmd);
 2898                         order = m->order;
 2899                         if (order < VM_NFREEORDER) {
 2900                                 /*
 2901                                  * The page is enqueued in the physical memory
 2902                                  * allocator's free page queues.  Moreover, it
 2903                                  * is the first page in a power-of-two-sized
 2904                                  * run of contiguous free pages.  Jump ahead
 2905                                  * to the last page within that run, and
 2906                                  * continue from there.
 2907                                  */
 2908                                 m += (1 << order) - 1;
 2909                         }
 2910 #if VM_NRESERVLEVEL > 0
 2911                         else if (vm_reserv_is_page_free(m))
 2912                                 order = 0;
 2913 #endif
 2914                         vm_domain_free_unlock(vmd);
 2915                         if (order == VM_NFREEORDER)
 2916                                 error = EINVAL;
 2917                 }
 2918         }
 2919         if ((m = SLIST_FIRST(&free)) != NULL) {
 2920                 int cnt;
 2921 
 2922                 vmd = VM_DOMAIN(domain);
 2923                 cnt = 0;
 2924                 vm_domain_free_lock(vmd);
 2925                 do {
 2926                         MPASS(vm_page_domain(m) == domain);
 2927                         SLIST_REMOVE_HEAD(&free, plinks.s.ss);
 2928                         vm_phys_free_pages(m, 0);
 2929                         cnt++;
 2930                 } while ((m = SLIST_FIRST(&free)) != NULL);
 2931                 vm_domain_free_unlock(vmd);
 2932                 vm_domain_freecnt_inc(vmd, cnt);
 2933         }
 2934         return (error);
 2935 }
 2936 
 2937 #define NRUNS   16
 2938 
 2939 CTASSERT(powerof2(NRUNS));
 2940 
 2941 #define RUN_INDEX(count)        ((count) & (NRUNS - 1))
 2942 
 2943 #define MIN_RECLAIM     8
 2944 
 2945 /*
 2946  *      vm_page_reclaim_contig:
 2947  *
 2948  *      Reclaim allocated, contiguous physical memory satisfying the specified
 2949  *      conditions by relocating the virtual pages using that physical memory.
 2950  *      Returns true if reclamation is successful and false otherwise.  Since
 2951  *      relocation requires the allocation of physical pages, reclamation may
 2952  *      fail due to a shortage of free pages.  When reclamation fails, callers
 2953  *      are expected to perform vm_wait() before retrying a failed allocation
 2954  *      operation, e.g., vm_page_alloc_contig().
 2955  *
 2956  *      The caller must always specify an allocation class through "req".
 2957  *
 2958  *      allocation classes:
 2959  *      VM_ALLOC_NORMAL         normal process request
 2960  *      VM_ALLOC_SYSTEM         system *really* needs a page
 2961  *      VM_ALLOC_INTERRUPT      interrupt time request
 2962  *
 2963  *      The optional allocation flags are ignored.
 2964  *
 2965  *      "npages" must be greater than zero.  Both "alignment" and "boundary"
 2966  *      must be a power of two.
 2967  */
 2968 bool
 2969 vm_page_reclaim_contig_domain(int domain, int req, u_long npages,
 2970     vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary)
 2971 {
 2972         struct vm_domain *vmd;
 2973         vm_paddr_t curr_low;
 2974         vm_page_t m_run, m_runs[NRUNS];
 2975         u_long count, reclaimed;
 2976         int error, i, options, req_class;
 2977 
 2978         KASSERT(npages > 0, ("npages is 0"));
 2979         KASSERT(powerof2(alignment), ("alignment is not a power of 2"));
 2980         KASSERT(powerof2(boundary), ("boundary is not a power of 2"));
 2981         req_class = req & VM_ALLOC_CLASS_MASK;
 2982 
 2983         /*
 2984          * The page daemon is allowed to dig deeper into the free page list.
 2985          */
 2986         if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT)
 2987                 req_class = VM_ALLOC_SYSTEM;
 2988 
 2989         /*
 2990          * Return if the number of free pages cannot satisfy the requested
 2991          * allocation.
 2992          */
 2993         vmd = VM_DOMAIN(domain);
 2994         count = vmd->vmd_free_count;
 2995         if (count < npages + vmd->vmd_free_reserved || (count < npages +
 2996             vmd->vmd_interrupt_free_min && req_class == VM_ALLOC_SYSTEM) ||
 2997             (count < npages && req_class == VM_ALLOC_INTERRUPT))
 2998                 return (false);
 2999 
 3000         /*
 3001          * Scan up to three times, relaxing the restrictions ("options") on
 3002          * the reclamation of reservations and superpages each time.
 3003          */
 3004         for (options = VPSC_NORESERV;;) {
 3005                 /*
 3006                  * Find the highest runs that satisfy the given constraints
 3007                  * and restrictions, and record them in "m_runs".
 3008                  */
 3009                 curr_low = low;
 3010                 count = 0;
 3011                 for (;;) {
 3012                         m_run = vm_phys_scan_contig(domain, npages, curr_low,
 3013                             high, alignment, boundary, options);
 3014                         if (m_run == NULL)
 3015                                 break;
 3016                         curr_low = VM_PAGE_TO_PHYS(m_run) + ptoa(npages);
 3017                         m_runs[RUN_INDEX(count)] = m_run;
 3018                         count++;
 3019                 }
 3020 
 3021                 /*
 3022                  * Reclaim the highest runs in LIFO (descending) order until
 3023                  * the number of reclaimed pages, "reclaimed", is at least
 3024                  * MIN_RECLAIM.  Reset "reclaimed" each time because each
 3025                  * reclamation is idempotent, and runs will (likely) recur
 3026                  * from one scan to the next as restrictions are relaxed.
 3027                  */
 3028                 reclaimed = 0;
 3029                 for (i = 0; count > 0 && i < NRUNS; i++) {
 3030                         count--;
 3031                         m_run = m_runs[RUN_INDEX(count)];
 3032                         error = vm_page_reclaim_run(req_class, domain, npages,
 3033                             m_run, high);
 3034                         if (error == 0) {
 3035                                 reclaimed += npages;
 3036                                 if (reclaimed >= MIN_RECLAIM)
 3037                                         return (true);
 3038                         }
 3039                 }
 3040 
 3041                 /*
 3042                  * Either relax the restrictions on the next scan or return if
 3043                  * the last scan had no restrictions.
 3044                  */
 3045                 if (options == VPSC_NORESERV)
 3046                         options = VPSC_NOSUPER;
 3047                 else if (options == VPSC_NOSUPER)
 3048                         options = VPSC_ANY;
 3049                 else if (options == VPSC_ANY)
 3050                         return (reclaimed != 0);
 3051         }
 3052 }
 3053 
 3054 bool
 3055 vm_page_reclaim_contig(int req, u_long npages, vm_paddr_t low, vm_paddr_t high,
 3056     u_long alignment, vm_paddr_t boundary)
 3057 {
 3058         struct vm_domainset_iter di;
 3059         int domain;
 3060         bool ret;
 3061 
 3062         vm_domainset_iter_page_init(&di, NULL, 0, &domain, &req);
 3063         do {
 3064                 ret = vm_page_reclaim_contig_domain(domain, req, npages, low,
 3065                     high, alignment, boundary);
 3066                 if (ret)
 3067                         break;
 3068         } while (vm_domainset_iter_page(&di, NULL, &domain) == 0);
 3069 
 3070         return (ret);
 3071 }
 3072 
 3073 /*
 3074  * Set the domain in the appropriate page level domainset.
 3075  */
 3076 void
 3077 vm_domain_set(struct vm_domain *vmd)
 3078 {
 3079 
 3080         mtx_lock(&vm_domainset_lock);
 3081         if (!vmd->vmd_minset && vm_paging_min(vmd)) {
 3082                 vmd->vmd_minset = 1;
 3083                 DOMAINSET_SET(vmd->vmd_domain, &vm_min_domains);
 3084         }
 3085         if (!vmd->vmd_severeset && vm_paging_severe(vmd)) {
 3086                 vmd->vmd_severeset = 1;
 3087                 DOMAINSET_SET(vmd->vmd_domain, &vm_severe_domains);
 3088         }
 3089         mtx_unlock(&vm_domainset_lock);
 3090 }
 3091 
 3092 /*
 3093  * Clear the domain from the appropriate page level domainset.
 3094  */
 3095 void
 3096 vm_domain_clear(struct vm_domain *vmd)
 3097 {
 3098 
 3099         mtx_lock(&vm_domainset_lock);
 3100         if (vmd->vmd_minset && !vm_paging_min(vmd)) {
 3101                 vmd->vmd_minset = 0;
 3102                 DOMAINSET_CLR(vmd->vmd_domain, &vm_min_domains);
 3103                 if (vm_min_waiters != 0) {
 3104                         vm_min_waiters = 0;
 3105                         wakeup(&vm_min_domains);
 3106                 }
 3107         }
 3108         if (vmd->vmd_severeset && !vm_paging_severe(vmd)) {
 3109                 vmd->vmd_severeset = 0;
 3110                 DOMAINSET_CLR(vmd->vmd_domain, &vm_severe_domains);
 3111                 if (vm_severe_waiters != 0) {
 3112                         vm_severe_waiters = 0;
 3113                         wakeup(&vm_severe_domains);
 3114                 }
 3115         }
 3116 
 3117         /*
 3118          * If pageout daemon needs pages, then tell it that there are
 3119          * some free.
 3120          */
 3121         if (vmd->vmd_pageout_pages_needed &&
 3122             vmd->vmd_free_count >= vmd->vmd_pageout_free_min) {
 3123                 wakeup(&vmd->vmd_pageout_pages_needed);
 3124                 vmd->vmd_pageout_pages_needed = 0;
 3125         }
 3126 
 3127         /* See comments in vm_wait_doms(). */
 3128         if (vm_pageproc_waiters) {
 3129                 vm_pageproc_waiters = 0;
 3130                 wakeup(&vm_pageproc_waiters);
 3131         }
 3132         mtx_unlock(&vm_domainset_lock);
 3133 }
 3134 
 3135 /*
 3136  * Wait for free pages to exceed the min threshold globally.
 3137  */
 3138 void
 3139 vm_wait_min(void)
 3140 {
 3141 
 3142         mtx_lock(&vm_domainset_lock);
 3143         while (vm_page_count_min()) {
 3144                 vm_min_waiters++;
 3145                 msleep(&vm_min_domains, &vm_domainset_lock, PVM, "vmwait", 0);
 3146         }
 3147         mtx_unlock(&vm_domainset_lock);
 3148 }
 3149 
 3150 /*
 3151  * Wait for free pages to exceed the severe threshold globally.
 3152  */
 3153 void
 3154 vm_wait_severe(void)
 3155 {
 3156 
 3157         mtx_lock(&vm_domainset_lock);
 3158         while (vm_page_count_severe()) {
 3159                 vm_severe_waiters++;
 3160                 msleep(&vm_severe_domains, &vm_domainset_lock, PVM,
 3161                     "vmwait", 0);
 3162         }
 3163         mtx_unlock(&vm_domainset_lock);
 3164 }
 3165 
 3166 u_int
 3167 vm_wait_count(void)
 3168 {
 3169 
 3170         return (vm_severe_waiters + vm_min_waiters + vm_pageproc_waiters);
 3171 }
 3172 
 3173 int
 3174 vm_wait_doms(const domainset_t *wdoms, int mflags)
 3175 {
 3176         int error;
 3177 
 3178         error = 0;
 3179 
 3180         /*
 3181          * We use racey wakeup synchronization to avoid expensive global
 3182          * locking for the pageproc when sleeping with a non-specific vm_wait.
 3183          * To handle this, we only sleep for one tick in this instance.  It
 3184          * is expected that most allocations for the pageproc will come from
 3185          * kmem or vm_page_grab* which will use the more specific and
 3186          * race-free vm_wait_domain().
 3187          */
 3188         if (curproc == pageproc) {
 3189                 mtx_lock(&vm_domainset_lock);
 3190                 vm_pageproc_waiters++;
 3191                 error = msleep(&vm_pageproc_waiters, &vm_domainset_lock,
 3192                     PVM | PDROP | mflags, "pageprocwait", 1);
 3193         } else {
 3194                 /*
 3195                  * XXX Ideally we would wait only until the allocation could
 3196                  * be satisfied.  This condition can cause new allocators to
 3197                  * consume all freed pages while old allocators wait.
 3198                  */
 3199                 mtx_lock(&vm_domainset_lock);
 3200                 if (vm_page_count_min_set(wdoms)) {
 3201                         vm_min_waiters++;
 3202                         error = msleep(&vm_min_domains, &vm_domainset_lock,
 3203                             PVM | PDROP | mflags, "vmwait", 0);
 3204                 } else
 3205                         mtx_unlock(&vm_domainset_lock);
 3206         }
 3207         return (error);
 3208 }
 3209 
 3210 /*
 3211  *      vm_wait_domain:
 3212  *
 3213  *      Sleep until free pages are available for allocation.
 3214  *      - Called in various places after failed memory allocations.
 3215  */
 3216 void
 3217 vm_wait_domain(int domain)
 3218 {
 3219         struct vm_domain *vmd;
 3220         domainset_t wdom;
 3221 
 3222         vmd = VM_DOMAIN(domain);
 3223         vm_domain_free_assert_unlocked(vmd);
 3224 
 3225         if (curproc == pageproc) {
 3226                 mtx_lock(&vm_domainset_lock);
 3227                 if (vmd->vmd_free_count < vmd->vmd_pageout_free_min) {
 3228                         vmd->vmd_pageout_pages_needed = 1;
 3229                         msleep(&vmd->vmd_pageout_pages_needed,
 3230                             &vm_domainset_lock, PDROP | PSWP, "VMWait", 0);
 3231                 } else
 3232                         mtx_unlock(&vm_domainset_lock);
 3233         } else {
 3234                 if (pageproc == NULL)
 3235                         panic("vm_wait in early boot");
 3236                 DOMAINSET_ZERO(&wdom);
 3237                 DOMAINSET_SET(vmd->vmd_domain, &wdom);
 3238                 vm_wait_doms(&wdom, 0);
 3239         }
 3240 }
 3241 
 3242 static int
 3243 vm_wait_flags(vm_object_t obj, int mflags)
 3244 {
 3245         struct domainset *d;
 3246 
 3247         d = NULL;
 3248 
 3249         /*
 3250          * Carefully fetch pointers only once: the struct domainset
 3251          * itself is ummutable but the pointer might change.
 3252          */
 3253         if (obj != NULL)
 3254                 d = obj->domain.dr_policy;
 3255         if (d == NULL)
 3256                 d = curthread->td_domain.dr_policy;
 3257 
 3258         return (vm_wait_doms(&d->ds_mask, mflags));
 3259 }
 3260 
 3261 /*
 3262  *      vm_wait:
 3263  *
 3264  *      Sleep until free pages are available for allocation in the
 3265  *      affinity domains of the obj.  If obj is NULL, the domain set
 3266  *      for the calling thread is used.
 3267  *      Called in various places after failed memory allocations.
 3268  */
 3269 void
 3270 vm_wait(vm_object_t obj)
 3271 {
 3272         (void)vm_wait_flags(obj, 0);
 3273 }
 3274 
 3275 int
 3276 vm_wait_intr(vm_object_t obj)
 3277 {
 3278         return (vm_wait_flags(obj, PCATCH));
 3279 }
 3280 
 3281 /*
 3282  *      vm_domain_alloc_fail:
 3283  *
 3284  *      Called when a page allocation function fails.  Informs the
 3285  *      pagedaemon and performs the requested wait.  Requires the
 3286  *      domain_free and object lock on entry.  Returns with the
 3287  *      object lock held and free lock released.  Returns an error when
 3288  *      retry is necessary.
 3289  *
 3290  */
 3291 static int
 3292 vm_domain_alloc_fail(struct vm_domain *vmd, vm_object_t object, int req)
 3293 {
 3294 
 3295         vm_domain_free_assert_unlocked(vmd);
 3296 
 3297         atomic_add_int(&vmd->vmd_pageout_deficit,
 3298             max((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1));
 3299         if (req & (VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL)) {
 3300                 if (object != NULL) 
 3301                         VM_OBJECT_WUNLOCK(object);
 3302                 vm_wait_domain(vmd->vmd_domain);
 3303                 if (object != NULL) 
 3304                         VM_OBJECT_WLOCK(object);
 3305                 if (req & VM_ALLOC_WAITOK)
 3306                         return (EAGAIN);
 3307         }
 3308 
 3309         return (0);
 3310 }
 3311 
 3312 /*
 3313  *      vm_waitpfault:
 3314  *
 3315  *      Sleep until free pages are available for allocation.
 3316  *      - Called only in vm_fault so that processes page faulting
 3317  *        can be easily tracked.
 3318  *      - Sleeps at a lower priority than vm_wait() so that vm_wait()ing
 3319  *        processes will be able to grab memory first.  Do not change
 3320  *        this balance without careful testing first.
 3321  */
 3322 void
 3323 vm_waitpfault(struct domainset *dset, int timo)
 3324 {
 3325 
 3326         /*
 3327          * XXX Ideally we would wait only until the allocation could
 3328          * be satisfied.  This condition can cause new allocators to
 3329          * consume all freed pages while old allocators wait.
 3330          */
 3331         mtx_lock(&vm_domainset_lock);
 3332         if (vm_page_count_min_set(&dset->ds_mask)) {
 3333                 vm_min_waiters++;
 3334                 msleep(&vm_min_domains, &vm_domainset_lock, PUSER | PDROP,
 3335                     "pfault", timo);
 3336         } else
 3337                 mtx_unlock(&vm_domainset_lock);
 3338 }
 3339 
 3340 static struct vm_pagequeue *
 3341 _vm_page_pagequeue(vm_page_t m, uint8_t queue)
 3342 {
 3343 
 3344         return (&vm_pagequeue_domain(m)->vmd_pagequeues[queue]);
 3345 }
 3346 
 3347 #ifdef INVARIANTS
 3348 static struct vm_pagequeue *
 3349 vm_page_pagequeue(vm_page_t m)
 3350 {
 3351 
 3352         return (_vm_page_pagequeue(m, vm_page_astate_load(m).queue));
 3353 }
 3354 #endif
 3355 
 3356 static __always_inline bool
 3357 vm_page_pqstate_fcmpset(vm_page_t m, vm_page_astate_t *old, vm_page_astate_t new)
 3358 {
 3359         vm_page_astate_t tmp;
 3360 
 3361         tmp = *old;
 3362         do {
 3363                 if (__predict_true(vm_page_astate_fcmpset(m, old, new)))
 3364                         return (true);
 3365                 counter_u64_add(pqstate_commit_retries, 1);
 3366         } while (old->_bits == tmp._bits);
 3367 
 3368         return (false);
 3369 }
 3370 
 3371 /*
 3372  * Do the work of committing a queue state update that moves the page out of
 3373  * its current queue.
 3374  */
 3375 static bool
 3376 _vm_page_pqstate_commit_dequeue(struct vm_pagequeue *pq, vm_page_t m,
 3377     vm_page_astate_t *old, vm_page_astate_t new)
 3378 {
 3379         vm_page_t next;
 3380 
 3381         vm_pagequeue_assert_locked(pq);
 3382         KASSERT(vm_page_pagequeue(m) == pq,
 3383             ("%s: queue %p does not match page %p", __func__, pq, m));
 3384         KASSERT(old->queue != PQ_NONE && new.queue != old->queue,
 3385             ("%s: invalid queue indices %d %d",
 3386             __func__, old->queue, new.queue));
 3387 
 3388         /*
 3389          * Once the queue index of the page changes there is nothing
 3390          * synchronizing with further updates to the page's physical
 3391          * queue state.  Therefore we must speculatively remove the page
 3392          * from the queue now and be prepared to roll back if the queue
 3393          * state update fails.  If the page is not physically enqueued then
 3394          * we just update its queue index.
 3395          */
 3396         if ((old->flags & PGA_ENQUEUED) != 0) {
 3397                 new.flags &= ~PGA_ENQUEUED;
 3398                 next = TAILQ_NEXT(m, plinks.q);
 3399                 TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
 3400                 vm_pagequeue_cnt_dec(pq);
 3401                 if (!vm_page_pqstate_fcmpset(m, old, new)) {
 3402                         if (next == NULL)
 3403                                 TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q);
 3404                         else
 3405                                 TAILQ_INSERT_BEFORE(next, m, plinks.q);
 3406                         vm_pagequeue_cnt_inc(pq);
 3407                         return (false);
 3408                 } else {
 3409                         return (true);
 3410                 }
 3411         } else {
 3412                 return (vm_page_pqstate_fcmpset(m, old, new));
 3413         }
 3414 }
 3415 
 3416 static bool
 3417 vm_page_pqstate_commit_dequeue(vm_page_t m, vm_page_astate_t *old,
 3418     vm_page_astate_t new)
 3419 {
 3420         struct vm_pagequeue *pq;
 3421         vm_page_astate_t as;
 3422         bool ret;
 3423 
 3424         pq = _vm_page_pagequeue(m, old->queue);
 3425 
 3426         /*
 3427          * The queue field and PGA_ENQUEUED flag are stable only so long as the
 3428          * corresponding page queue lock is held.
 3429          */
 3430         vm_pagequeue_lock(pq);
 3431         as = vm_page_astate_load(m);
 3432         if (__predict_false(as._bits != old->_bits)) {
 3433                 *old = as;
 3434                 ret = false;
 3435         } else {
 3436                 ret = _vm_page_pqstate_commit_dequeue(pq, m, old, new);
 3437         }
 3438         vm_pagequeue_unlock(pq);
 3439         return (ret);
 3440 }
 3441 
 3442 /*
 3443  * Commit a queue state update that enqueues or requeues a page.
 3444  */
 3445 static bool
 3446 _vm_page_pqstate_commit_requeue(struct vm_pagequeue *pq, vm_page_t m,
 3447     vm_page_astate_t *old, vm_page_astate_t new)
 3448 {
 3449         struct vm_domain *vmd;
 3450 
 3451         vm_pagequeue_assert_locked(pq);
 3452         KASSERT(old->queue != PQ_NONE && new.queue == old->queue,
 3453             ("%s: invalid queue indices %d %d",
 3454             __func__, old->queue, new.queue));
 3455 
 3456         new.flags |= PGA_ENQUEUED;
 3457         if (!vm_page_pqstate_fcmpset(m, old, new))
 3458                 return (false);
 3459 
 3460         if ((old->flags & PGA_ENQUEUED) != 0)
 3461                 TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
 3462         else
 3463                 vm_pagequeue_cnt_inc(pq);
 3464 
 3465         /*
 3466          * Give PGA_REQUEUE_HEAD precedence over PGA_REQUEUE.  In particular, if
 3467          * both flags are set in close succession, only PGA_REQUEUE_HEAD will be
 3468          * applied, even if it was set first.
 3469          */
 3470         if ((old->flags & PGA_REQUEUE_HEAD) != 0) {
 3471                 vmd = vm_pagequeue_domain(m);
 3472                 KASSERT(pq == &vmd->vmd_pagequeues[PQ_INACTIVE],
 3473                     ("%s: invalid page queue for page %p", __func__, m));
 3474                 TAILQ_INSERT_BEFORE(&vmd->vmd_inacthead, m, plinks.q);
 3475         } else {
 3476                 TAILQ_INSERT_TAIL(&pq->pq_pl, m, plinks.q);
 3477         }
 3478         return (true);
 3479 }
 3480 
 3481 /*
 3482  * Commit a queue state update that encodes a request for a deferred queue
 3483  * operation.
 3484  */
 3485 static bool
 3486 vm_page_pqstate_commit_request(vm_page_t m, vm_page_astate_t *old,
 3487     vm_page_astate_t new)
 3488 {
 3489 
 3490         KASSERT(old->queue == new.queue || new.queue != PQ_NONE,
 3491             ("%s: invalid state, queue %d flags %x",
 3492             __func__, new.queue, new.flags));
 3493 
 3494         if (old->_bits != new._bits &&
 3495             !vm_page_pqstate_fcmpset(m, old, new))
 3496                 return (false);
 3497         vm_page_pqbatch_submit(m, new.queue);
 3498         return (true);
 3499 }
 3500 
 3501 /*
 3502  * A generic queue state update function.  This handles more cases than the
 3503  * specialized functions above.
 3504  */
 3505 bool
 3506 vm_page_pqstate_commit(vm_page_t m, vm_page_astate_t *old, vm_page_astate_t new)
 3507 {
 3508 
 3509         if (old->_bits == new._bits)
 3510                 return (true);
 3511 
 3512         if (old->queue != PQ_NONE && new.queue != old->queue) {
 3513                 if (!vm_page_pqstate_commit_dequeue(m, old, new))
 3514                         return (false);
 3515                 if (new.queue != PQ_NONE)
 3516                         vm_page_pqbatch_submit(m, new.queue);
 3517         } else {
 3518                 if (!vm_page_pqstate_fcmpset(m, old, new))
 3519                         return (false);
 3520                 if (new.queue != PQ_NONE &&
 3521                     ((new.flags & ~old->flags) & PGA_QUEUE_OP_MASK) != 0)
 3522                         vm_page_pqbatch_submit(m, new.queue);
 3523         }
 3524         return (true);
 3525 }
 3526 
 3527 /*
 3528  * Apply deferred queue state updates to a page.
 3529  */
 3530 static inline void
 3531 vm_pqbatch_process_page(struct vm_pagequeue *pq, vm_page_t m, uint8_t queue)
 3532 {
 3533         vm_page_astate_t new, old;
 3534 
 3535         CRITICAL_ASSERT(curthread);
 3536         vm_pagequeue_assert_locked(pq);
 3537         KASSERT(queue < PQ_COUNT,
 3538             ("%s: invalid queue index %d", __func__, queue));
 3539         KASSERT(pq == _vm_page_pagequeue(m, queue),
 3540             ("%s: page %p does not belong to queue %p", __func__, m, pq));
 3541 
 3542         for (old = vm_page_astate_load(m);;) {
 3543                 if (__predict_false(old.queue != queue ||
 3544                     (old.flags & PGA_QUEUE_OP_MASK) == 0)) {
 3545                         counter_u64_add(queue_nops, 1);
 3546                         break;
 3547                 }
 3548                 KASSERT(old.queue != PQ_NONE ||
 3549                     (old.flags & PGA_QUEUE_STATE_MASK) == 0,
 3550                     ("%s: page %p has unexpected queue state", __func__, m));
 3551 
 3552                 new = old;
 3553                 if ((old.flags & PGA_DEQUEUE) != 0) {
 3554                         new.flags &= ~PGA_QUEUE_OP_MASK;
 3555                         new.queue = PQ_NONE;
 3556                         if (__predict_true(_vm_page_pqstate_commit_dequeue(pq,
 3557                             m, &old, new))) {
 3558                                 counter_u64_add(queue_ops, 1);
 3559                                 break;
 3560                         }
 3561                 } else {
 3562                         new.flags &= ~(PGA_REQUEUE | PGA_REQUEUE_HEAD);
 3563                         if (__predict_true(_vm_page_pqstate_commit_requeue(pq,
 3564                             m, &old, new))) {
 3565                                 counter_u64_add(queue_ops, 1);
 3566                                 break;
 3567                         }
 3568                 }
 3569         }
 3570 }
 3571 
 3572 static void
 3573 vm_pqbatch_process(struct vm_pagequeue *pq, struct vm_batchqueue *bq,
 3574     uint8_t queue)
 3575 {
 3576         int i;
 3577 
 3578         for (i = 0; i < bq->bq_cnt; i++)
 3579                 vm_pqbatch_process_page(pq, bq->bq_pa[i], queue);
 3580         vm_batchqueue_init(bq);
 3581 }
 3582 
 3583 /*
 3584  *      vm_page_pqbatch_submit:         [ internal use only ]
 3585  *
 3586  *      Enqueue a page in the specified page queue's batched work queue.
 3587  *      The caller must have encoded the requested operation in the page
 3588  *      structure's a.flags field.
 3589  */
 3590 void
 3591 vm_page_pqbatch_submit(vm_page_t m, uint8_t queue)
 3592 {
 3593         struct vm_batchqueue *bq;
 3594         struct vm_pagequeue *pq;
 3595         int domain;
 3596 
 3597         KASSERT((m->oflags & VPO_UNMANAGED) == 0,
 3598             ("page %p is unmanaged", m));
 3599         KASSERT(queue < PQ_COUNT, ("invalid queue %d", queue));
 3600 
 3601         domain = vm_page_domain(m);
 3602         critical_enter();
 3603         bq = DPCPU_PTR(pqbatch[domain][queue]);
 3604         if (vm_batchqueue_insert(bq, m)) {
 3605                 critical_exit();
 3606                 return;
 3607         }
 3608         critical_exit();
 3609 
 3610         pq = &VM_DOMAIN(domain)->vmd_pagequeues[queue];
 3611         vm_pagequeue_lock(pq);
 3612         critical_enter();
 3613         bq = DPCPU_PTR(pqbatch[domain][queue]);
 3614         vm_pqbatch_process(pq, bq, queue);
 3615         vm_pqbatch_process_page(pq, m, queue);
 3616         vm_pagequeue_unlock(pq);
 3617         critical_exit();
 3618 }
 3619 
 3620 /*
 3621  *      vm_page_pqbatch_drain:          [ internal use only ]
 3622  *
 3623  *      Force all per-CPU page queue batch queues to be drained.  This is
 3624  *      intended for use in severe memory shortages, to ensure that pages
 3625  *      do not remain stuck in the batch queues.
 3626  */
 3627 void
 3628 vm_page_pqbatch_drain(void)
 3629 {
 3630         struct thread *td;
 3631         struct vm_domain *vmd;
 3632         struct vm_pagequeue *pq;
 3633         int cpu, domain, queue;
 3634 
 3635         td = curthread;
 3636         CPU_FOREACH(cpu) {
 3637                 thread_lock(td);
 3638                 sched_bind(td, cpu);
 3639                 thread_unlock(td);
 3640 
 3641                 for (domain = 0; domain < vm_ndomains; domain++) {
 3642                         vmd = VM_DOMAIN(domain);
 3643                         for (queue = 0; queue < PQ_COUNT; queue++) {
 3644                                 pq = &vmd->vmd_pagequeues[queue];
 3645                                 vm_pagequeue_lock(pq);
 3646                                 critical_enter();
 3647                                 vm_pqbatch_process(pq,
 3648                                     DPCPU_PTR(pqbatch[domain][queue]), queue);
 3649                                 critical_exit();
 3650                                 vm_pagequeue_unlock(pq);
 3651                         }
 3652                 }
 3653         }
 3654         thread_lock(td);
 3655         sched_unbind(td);
 3656         thread_unlock(td);
 3657 }
 3658 
 3659 /*
 3660  *      vm_page_dequeue_deferred:       [ internal use only ]
 3661  *
 3662  *      Request removal of the given page from its current page
 3663  *      queue.  Physical removal from the queue may be deferred
 3664  *      indefinitely.
 3665  */
 3666 void
 3667 vm_page_dequeue_deferred(vm_page_t m)
 3668 {
 3669         vm_page_astate_t new, old;
 3670 
 3671         old = vm_page_astate_load(m);
 3672         do {
 3673                 if (old.queue == PQ_NONE) {
 3674                         KASSERT((old.flags & PGA_QUEUE_STATE_MASK) == 0,
 3675                             ("%s: page %p has unexpected queue state",
 3676                             __func__, m));
 3677                         break;
 3678                 }
 3679                 new = old;
 3680                 new.flags |= PGA_DEQUEUE;
 3681         } while (!vm_page_pqstate_commit_request(m, &old, new));
 3682 }
 3683 
 3684 /*
 3685  *      vm_page_dequeue:
 3686  *
 3687  *      Remove the page from whichever page queue it's in, if any, before
 3688  *      returning.
 3689  */
 3690 void
 3691 vm_page_dequeue(vm_page_t m)
 3692 {
 3693         vm_page_astate_t new, old;
 3694 
 3695         old = vm_page_astate_load(m);
 3696         do {
 3697                 if (old.queue == PQ_NONE) {
 3698                         KASSERT((old.flags & PGA_QUEUE_STATE_MASK) == 0,
 3699                             ("%s: page %p has unexpected queue state",
 3700                             __func__, m));
 3701                         break;
 3702                 }
 3703                 new = old;
 3704                 new.flags &= ~PGA_QUEUE_OP_MASK;
 3705                 new.queue = PQ_NONE;
 3706         } while (!vm_page_pqstate_commit_dequeue(m, &old, new));
 3707 
 3708 }
 3709 
 3710 /*
 3711  * Schedule the given page for insertion into the specified page queue.
 3712  * Physical insertion of the page may be deferred indefinitely.
 3713  */
 3714 static void
 3715 vm_page_enqueue(vm_page_t m, uint8_t queue)
 3716 {
 3717 
 3718         KASSERT(m->a.queue == PQ_NONE &&
 3719             (m->a.flags & PGA_QUEUE_STATE_MASK) == 0,
 3720             ("%s: page %p is already enqueued", __func__, m));
 3721         KASSERT(m->ref_count > 0,
 3722             ("%s: page %p does not carry any references", __func__, m));
 3723 
 3724         m->a.queue = queue;
 3725         if ((m->a.flags & PGA_REQUEUE) == 0)
 3726                 vm_page_aflag_set(m, PGA_REQUEUE);
 3727         vm_page_pqbatch_submit(m, queue);
 3728 }
 3729 
 3730 /*
 3731  *      vm_page_free_prep:
 3732  *
 3733  *      Prepares the given page to be put on the free list,
 3734  *      disassociating it from any VM object. The caller may return
 3735  *      the page to the free list only if this function returns true.
 3736  *
 3737  *      The object, if it exists, must be locked, and then the page must
 3738  *      be xbusy.  Otherwise the page must be not busied.  A managed
 3739  *      page must be unmapped.
 3740  */
 3741 static bool
 3742 vm_page_free_prep(vm_page_t m)
 3743 {
 3744 
 3745         /*
 3746          * Synchronize with threads that have dropped a reference to this
 3747          * page.
 3748          */
 3749         atomic_thread_fence_acq();
 3750 
 3751 #if defined(DIAGNOSTIC) && defined(PHYS_TO_DMAP)
 3752         if (PMAP_HAS_DMAP && (m->flags & PG_ZERO) != 0) {
 3753                 uint64_t *p;
 3754                 int i;
 3755                 p = (uint64_t *)PHYS_TO_DMAP(VM_PAGE_TO_PHYS(m));
 3756                 for (i = 0; i < PAGE_SIZE / sizeof(uint64_t); i++, p++)
 3757                         KASSERT(*p == 0, ("vm_page_free_prep %p PG_ZERO %d %jx",
 3758                             m, i, (uintmax_t)*p));
 3759         }
 3760 #endif
 3761         if ((m->oflags & VPO_UNMANAGED) == 0) {
 3762                 KASSERT(!pmap_page_is_mapped(m),
 3763                     ("vm_page_free_prep: freeing mapped page %p", m));
 3764                 KASSERT((m->a.flags & (PGA_EXECUTABLE | PGA_WRITEABLE)) == 0,
 3765                     ("vm_page_free_prep: mapping flags set in page %p", m));
 3766         } else {
 3767                 KASSERT(m->a.queue == PQ_NONE,
 3768                     ("vm_page_free_prep: unmanaged page %p is queued", m));
 3769         }
 3770         VM_CNT_INC(v_tfree);
 3771 
 3772         if (m->object != NULL) {
 3773                 KASSERT(((m->oflags & VPO_UNMANAGED) != 0) ==
 3774                     ((m->object->flags & OBJ_UNMANAGED) != 0),
 3775                     ("vm_page_free_prep: managed flag mismatch for page %p",
 3776                     m));
 3777                 vm_page_assert_xbusied(m);
 3778 
 3779                 /*
 3780                  * The object reference can be released without an atomic
 3781                  * operation.
 3782                  */
 3783                 KASSERT((m->flags & PG_FICTITIOUS) != 0 ||
 3784                     m->ref_count == VPRC_OBJREF,
 3785                     ("vm_page_free_prep: page %p has unexpected ref_count %u",
 3786                     m, m->ref_count));
 3787                 vm_page_object_remove(m);
 3788                 m->ref_count -= VPRC_OBJREF;
 3789         } else
 3790                 vm_page_assert_unbusied(m);
 3791 
 3792         vm_page_busy_free(m);
 3793 
 3794         /*
 3795          * If fictitious remove object association and
 3796          * return.
 3797          */
 3798         if ((m->flags & PG_FICTITIOUS) != 0) {
 3799                 KASSERT(m->ref_count == 1,
 3800                     ("fictitious page %p is referenced", m));
 3801                 KASSERT(m->a.queue == PQ_NONE,
 3802                     ("fictitious page %p is queued", m));
 3803                 return (false);
 3804         }
 3805 
 3806         /*
 3807          * Pages need not be dequeued before they are returned to the physical
 3808          * memory allocator, but they must at least be marked for a deferred
 3809          * dequeue.
 3810          */
 3811         if ((m->oflags & VPO_UNMANAGED) == 0)
 3812                 vm_page_dequeue_deferred(m);
 3813 
 3814         m->valid = 0;
 3815         vm_page_undirty(m);
 3816 
 3817         if (m->ref_count != 0)
 3818                 panic("vm_page_free_prep: page %p has references", m);
 3819 
 3820         /*
 3821          * Restore the default memory attribute to the page.
 3822          */
 3823         if (pmap_page_get_memattr(m) != VM_MEMATTR_DEFAULT)
 3824                 pmap_page_set_memattr(m, VM_MEMATTR_DEFAULT);
 3825 
 3826 #if VM_NRESERVLEVEL > 0
 3827         /*
 3828          * Determine whether the page belongs to a reservation.  If the page was
 3829          * allocated from a per-CPU cache, it cannot belong to a reservation, so
 3830          * as an optimization, we avoid the check in that case.
 3831          */
 3832         if ((m->flags & PG_PCPU_CACHE) == 0 && vm_reserv_free_page(m))
 3833                 return (false);
 3834 #endif
 3835 
 3836         return (true);
 3837 }
 3838 
 3839 /*
 3840  *      vm_page_free_toq:
 3841  *
 3842  *      Returns the given page to the free list, disassociating it
 3843  *      from any VM object.
 3844  *
 3845  *      The object must be locked.  The page must be exclusively busied if it
 3846  *      belongs to an object.
 3847  */
 3848 static void
 3849 vm_page_free_toq(vm_page_t m)
 3850 {
 3851         struct vm_domain *vmd;
 3852         uma_zone_t zone;
 3853 
 3854         if (!vm_page_free_prep(m))
 3855                 return;
 3856 
 3857         vmd = vm_pagequeue_domain(m);
 3858         zone = vmd->vmd_pgcache[m->pool].zone;
 3859         if ((m->flags & PG_PCPU_CACHE) != 0 && zone != NULL) {
 3860                 uma_zfree(zone, m);
 3861                 return;
 3862         }
 3863         vm_domain_free_lock(vmd);
 3864         vm_phys_free_pages(m, 0);
 3865         vm_domain_free_unlock(vmd);
 3866         vm_domain_freecnt_inc(vmd, 1);
 3867 }
 3868 
 3869 /*
 3870  *      vm_page_free_pages_toq:
 3871  *
 3872  *      Returns a list of pages to the free list, disassociating it
 3873  *      from any VM object.  In other words, this is equivalent to
 3874  *      calling vm_page_free_toq() for each page of a list of VM objects.
 3875  */
 3876 void
 3877 vm_page_free_pages_toq(struct spglist *free, bool update_wire_count)
 3878 {
 3879         vm_page_t m;
 3880         int count;
 3881 
 3882         if (SLIST_EMPTY(free))
 3883                 return;
 3884 
 3885         count = 0;
 3886         while ((m = SLIST_FIRST(free)) != NULL) {
 3887                 count++;
 3888                 SLIST_REMOVE_HEAD(free, plinks.s.ss);
 3889                 vm_page_free_toq(m);
 3890         }
 3891 
 3892         if (update_wire_count)
 3893                 vm_wire_sub(count);
 3894 }
 3895 
 3896 /*
 3897  * Mark this page as wired down.  For managed pages, this prevents reclamation
 3898  * by the page daemon, or when the containing object, if any, is destroyed.
 3899  */
 3900 void
 3901 vm_page_wire(vm_page_t m)
 3902 {
 3903         u_int old;
 3904 
 3905 #ifdef INVARIANTS
 3906         if (m->object != NULL && !vm_page_busied(m) &&
 3907             !vm_object_busied(m->object))
 3908                 VM_OBJECT_ASSERT_LOCKED(m->object);
 3909 #endif
 3910         KASSERT((m->flags & PG_FICTITIOUS) == 0 ||
 3911             VPRC_WIRE_COUNT(m->ref_count) >= 1,
 3912             ("vm_page_wire: fictitious page %p has zero wirings", m));
 3913 
 3914         old = atomic_fetchadd_int(&m->ref_count, 1);
 3915         KASSERT(VPRC_WIRE_COUNT(old) != VPRC_WIRE_COUNT_MAX,
 3916             ("vm_page_wire: counter overflow for page %p", m));
 3917         if (VPRC_WIRE_COUNT(old) == 0) {
 3918                 if ((m->oflags & VPO_UNMANAGED) == 0)
 3919                         vm_page_aflag_set(m, PGA_DEQUEUE);
 3920                 vm_wire_add(1);
 3921         }
 3922 }
 3923 
 3924 /*
 3925  * Attempt to wire a mapped page following a pmap lookup of that page.
 3926  * This may fail if a thread is concurrently tearing down mappings of the page.
 3927  * The transient failure is acceptable because it translates to the
 3928  * failure of the caller pmap_extract_and_hold(), which should be then
 3929  * followed by the vm_fault() fallback, see e.g. vm_fault_quick_hold_pages().
 3930  */
 3931 bool
 3932 vm_page_wire_mapped(vm_page_t m)
 3933 {
 3934         u_int old;
 3935 
 3936         old = m->ref_count;
 3937         do {
 3938                 KASSERT(old > 0,
 3939                     ("vm_page_wire_mapped: wiring unreferenced page %p", m));
 3940                 if ((old & VPRC_BLOCKED) != 0)
 3941                         return (false);
 3942         } while (!atomic_fcmpset_int(&m->ref_count, &old, old + 1));
 3943 
 3944         if (VPRC_WIRE_COUNT(old) == 0) {
 3945                 if ((m->oflags & VPO_UNMANAGED) == 0)
 3946                         vm_page_aflag_set(m, PGA_DEQUEUE);
 3947                 vm_wire_add(1);
 3948         }
 3949         return (true);
 3950 }
 3951 
 3952 /*
 3953  * Release a wiring reference to a managed page.  If the page still belongs to
 3954  * an object, update its position in the page queues to reflect the reference.
 3955  * If the wiring was the last reference to the page, free the page.
 3956  */
 3957 static void
 3958 vm_page_unwire_managed(vm_page_t m, uint8_t nqueue, bool noreuse)
 3959 {
 3960         u_int old;
 3961 
 3962         KASSERT((m->oflags & VPO_UNMANAGED) == 0,
 3963             ("%s: page %p is unmanaged", __func__, m));
 3964 
 3965         /*
 3966          * Update LRU state before releasing the wiring reference.
 3967          * Use a release store when updating the reference count to
 3968          * synchronize with vm_page_free_prep().
 3969          */
 3970         old = m->ref_count;
 3971         do {
 3972                 KASSERT(VPRC_WIRE_COUNT(old) > 0,
 3973                     ("vm_page_unwire: wire count underflow for page %p", m));
 3974 
 3975                 if (old > VPRC_OBJREF + 1) {
 3976                         /*
 3977                          * The page has at least one other wiring reference.  An
 3978                          * earlier iteration of this loop may have called
 3979                          * vm_page_release_toq() and cleared PGA_DEQUEUE, so
 3980                          * re-set it if necessary.
 3981                          */
 3982                         if ((vm_page_astate_load(m).flags & PGA_DEQUEUE) == 0)
 3983                                 vm_page_aflag_set(m, PGA_DEQUEUE);
 3984                 } else if (old == VPRC_OBJREF + 1) {
 3985                         /*
 3986                          * This is the last wiring.  Clear PGA_DEQUEUE and
 3987                          * update the page's queue state to reflect the
 3988                          * reference.  If the page does not belong to an object
 3989                          * (i.e., the VPRC_OBJREF bit is clear), we only need to
 3990                          * clear leftover queue state.
 3991                          */
 3992                         vm_page_release_toq(m, nqueue, noreuse);
 3993                 } else if (old == 1) {
 3994                         vm_page_aflag_clear(m, PGA_DEQUEUE);
 3995                 }
 3996         } while (!atomic_fcmpset_rel_int(&m->ref_count, &old, old - 1));
 3997 
 3998         if (VPRC_WIRE_COUNT(old) == 1) {
 3999                 vm_wire_sub(1);
 4000                 if (old == 1)
 4001                         vm_page_free(m);
 4002         }
 4003 }
 4004 
 4005 /*
 4006  * Release one wiring of the specified page, potentially allowing it to be
 4007  * paged out.
 4008  *
 4009  * Only managed pages belonging to an object can be paged out.  If the number
 4010  * of wirings transitions to zero and the page is eligible for page out, then
 4011  * the page is added to the specified paging queue.  If the released wiring
 4012  * represented the last reference to the page, the page is freed.
 4013  */
 4014 void
 4015 vm_page_unwire(vm_page_t m, uint8_t nqueue)
 4016 {
 4017 
 4018         KASSERT(nqueue < PQ_COUNT,
 4019             ("vm_page_unwire: invalid queue %u request for page %p",
 4020             nqueue, m));
 4021 
 4022         if ((m->oflags & VPO_UNMANAGED) != 0) {
 4023                 if (vm_page_unwire_noq(m) && m->ref_count == 0)
 4024                         vm_page_free(m);
 4025                 return;
 4026         }
 4027         vm_page_unwire_managed(m, nqueue, false);
 4028 }
 4029 
 4030 /*
 4031  * Unwire a page without (re-)inserting it into a page queue.  It is up
 4032  * to the caller to enqueue, requeue, or free the page as appropriate.
 4033  * In most cases involving managed pages, vm_page_unwire() should be used
 4034  * instead.
 4035  */
 4036 bool
 4037 vm_page_unwire_noq(vm_page_t m)
 4038 {
 4039         u_int old;
 4040 
 4041         old = vm_page_drop(m, 1);
 4042         KASSERT(VPRC_WIRE_COUNT(old) != 0,
 4043             ("vm_page_unref: counter underflow for page %p", m));
 4044         KASSERT((m->flags & PG_FICTITIOUS) == 0 || VPRC_WIRE_COUNT(old) > 1,
 4045             ("vm_page_unref: missing ref on fictitious page %p", m));
 4046 
 4047         if (VPRC_WIRE_COUNT(old) > 1)
 4048                 return (false);
 4049         if ((m->oflags & VPO_UNMANAGED) == 0)
 4050                 vm_page_aflag_clear(m, PGA_DEQUEUE);
 4051         vm_wire_sub(1);
 4052         return (true);
 4053 }
 4054 
 4055 /*
 4056  * Ensure that the page ends up in the specified page queue.  If the page is
 4057  * active or being moved to the active queue, ensure that its act_count is
 4058  * at least ACT_INIT but do not otherwise mess with it.
 4059  */
 4060 static __always_inline void
 4061 vm_page_mvqueue(vm_page_t m, const uint8_t nqueue, const uint16_t nflag)
 4062 {
 4063         vm_page_astate_t old, new;
 4064 
 4065         KASSERT(m->ref_count > 0,
 4066             ("%s: page %p does not carry any references", __func__, m));
 4067         KASSERT(nflag == PGA_REQUEUE || nflag == PGA_REQUEUE_HEAD,
 4068             ("%s: invalid flags %x", __func__, nflag));
 4069 
 4070         if ((m->oflags & VPO_UNMANAGED) != 0 || vm_page_wired(m))
 4071                 return;
 4072 
 4073         old = vm_page_astate_load(m);
 4074         do {
 4075                 if ((old.flags & PGA_DEQUEUE) != 0)
 4076                         break;
 4077                 new = old;
 4078                 new.flags &= ~PGA_QUEUE_OP_MASK;
 4079                 if (nqueue == PQ_ACTIVE)
 4080                         new.act_count = max(old.act_count, ACT_INIT);
 4081                 if (old.queue == nqueue) {
 4082                         if (nqueue != PQ_ACTIVE)
 4083                                 new.flags |= nflag;
 4084                 } else {
 4085                         new.flags |= nflag;
 4086                         new.queue = nqueue;
 4087                 }
 4088         } while (!vm_page_pqstate_commit(m, &old, new));
 4089 }
 4090 
 4091 /*
 4092  * Put the specified page on the active list (if appropriate).
 4093  */
 4094 void
 4095 vm_page_activate(vm_page_t m)
 4096 {
 4097 
 4098         vm_page_mvqueue(m, PQ_ACTIVE, PGA_REQUEUE);
 4099 }
 4100 
 4101 /*
 4102  * Move the specified page to the tail of the inactive queue, or requeue
 4103  * the page if it is already in the inactive queue.
 4104  */
 4105 void
 4106 vm_page_deactivate(vm_page_t m)
 4107 {
 4108 
 4109         vm_page_mvqueue(m, PQ_INACTIVE, PGA_REQUEUE);
 4110 }
 4111 
 4112 void
 4113 vm_page_deactivate_noreuse(vm_page_t m)
 4114 {
 4115 
 4116         vm_page_mvqueue(m, PQ_INACTIVE, PGA_REQUEUE_HEAD);
 4117 }
 4118 
 4119 /*
 4120  * Put a page in the laundry, or requeue it if it is already there.
 4121  */
 4122 void
 4123 vm_page_launder(vm_page_t m)
 4124 {
 4125 
 4126         vm_page_mvqueue(m, PQ_LAUNDRY, PGA_REQUEUE);
 4127 }
 4128 
 4129 /*
 4130  * Put a page in the PQ_UNSWAPPABLE holding queue.
 4131  */
 4132 void
 4133 vm_page_unswappable(vm_page_t m)
 4134 {
 4135 
 4136         KASSERT(!vm_page_wired(m) && (m->oflags & VPO_UNMANAGED) == 0,
 4137             ("page %p already unswappable", m));
 4138 
 4139         vm_page_dequeue(m);
 4140         vm_page_enqueue(m, PQ_UNSWAPPABLE);
 4141 }
 4142 
 4143 /*
 4144  * Release a page back to the page queues in preparation for unwiring.
 4145  */
 4146 static void
 4147 vm_page_release_toq(vm_page_t m, uint8_t nqueue, const bool noreuse)
 4148 {
 4149         vm_page_astate_t old, new;
 4150         uint16_t nflag;
 4151 
 4152         /*
 4153          * Use a check of the valid bits to determine whether we should
 4154          * accelerate reclamation of the page.  The object lock might not be
 4155          * held here, in which case the check is racy.  At worst we will either
 4156          * accelerate reclamation of a valid page and violate LRU, or
 4157          * unnecessarily defer reclamation of an invalid page.
 4158          *
 4159          * If we were asked to not cache the page, place it near the head of the
 4160          * inactive queue so that is reclaimed sooner.
 4161          */
 4162         if (noreuse || m->valid == 0) {
 4163                 nqueue = PQ_INACTIVE;
 4164                 nflag = PGA_REQUEUE_HEAD;
 4165         } else {
 4166                 nflag = PGA_REQUEUE;
 4167         }
 4168 
 4169         old = vm_page_astate_load(m);
 4170         do {
 4171                 new = old;
 4172 
 4173                 /*
 4174                  * If the page is already in the active queue and we are not
 4175                  * trying to accelerate reclamation, simply mark it as
 4176                  * referenced and avoid any queue operations.
 4177                  */
 4178                 new.flags &= ~PGA_QUEUE_OP_MASK;
 4179                 if (nflag != PGA_REQUEUE_HEAD && old.queue == PQ_ACTIVE)
 4180                         new.flags |= PGA_REFERENCED;
 4181                 else {
 4182                         new.flags |= nflag;
 4183                         new.queue = nqueue;
 4184                 }
 4185         } while (!vm_page_pqstate_commit(m, &old, new));
 4186 }
 4187 
 4188 /*
 4189  * Unwire a page and either attempt to free it or re-add it to the page queues.
 4190  */
 4191 void
 4192 vm_page_release(vm_page_t m, int flags)
 4193 {
 4194         vm_object_t object;
 4195 
 4196         KASSERT((m->oflags & VPO_UNMANAGED) == 0,
 4197             ("vm_page_release: page %p is unmanaged", m));
 4198 
 4199         if ((flags & VPR_TRYFREE) != 0) {
 4200                 for (;;) {
 4201                         object = atomic_load_ptr(&m->object);
 4202                         if (object == NULL)
 4203                                 break;
 4204                         /* Depends on type-stability. */
 4205                         if (vm_page_busied(m) || !VM_OBJECT_TRYWLOCK(object))
 4206                                 break;
 4207                         if (object == m->object) {
 4208                                 vm_page_release_locked(m, flags);
 4209                                 VM_OBJECT_WUNLOCK(object);
 4210                                 return;
 4211                         }
 4212                         VM_OBJECT_WUNLOCK(object);
 4213                 }
 4214         }
 4215         vm_page_unwire_managed(m, PQ_INACTIVE, flags != 0);
 4216 }
 4217 
 4218 /* See vm_page_release(). */
 4219 void
 4220 vm_page_release_locked(vm_page_t m, int flags)
 4221 {
 4222 
 4223         VM_OBJECT_ASSERT_WLOCKED(m->object);
 4224         KASSERT((m->oflags & VPO_UNMANAGED) == 0,
 4225             ("vm_page_release_locked: page %p is unmanaged", m));
 4226 
 4227         if (vm_page_unwire_noq(m)) {
 4228                 if ((flags & VPR_TRYFREE) != 0 &&
 4229                     (m->object->ref_count == 0 || !pmap_page_is_mapped(m)) &&
 4230                     m->dirty == 0 && vm_page_tryxbusy(m)) {
 4231                         /*
 4232                          * An unlocked lookup may have wired the page before the
 4233                          * busy lock was acquired, in which case the page must
 4234                          * not be freed.
 4235                          */
 4236                         if (__predict_true(!vm_page_wired(m))) {
 4237                                 vm_page_free(m);
 4238                                 return;
 4239                         }
 4240                         vm_page_xunbusy(m);
 4241                 } else {
 4242                         vm_page_release_toq(m, PQ_INACTIVE, flags != 0);
 4243                 }
 4244         }
 4245 }
 4246 
 4247 static bool
 4248 vm_page_try_blocked_op(vm_page_t m, void (*op)(vm_page_t))
 4249 {
 4250         u_int old;
 4251 
 4252         KASSERT(m->object != NULL && (m->oflags & VPO_UNMANAGED) == 0,
 4253             ("vm_page_try_blocked_op: page %p has no object", m));
 4254         KASSERT(vm_page_busied(m),
 4255             ("vm_page_try_blocked_op: page %p is not busy", m));
 4256         VM_OBJECT_ASSERT_LOCKED(m->object);
 4257 
 4258         old = m->ref_count;
 4259         do {
 4260                 KASSERT(old != 0,
 4261                     ("vm_page_try_blocked_op: page %p has no references", m));
 4262                 if (VPRC_WIRE_COUNT(old) != 0)
 4263                         return (false);
 4264         } while (!atomic_fcmpset_int(&m->ref_count, &old, old | VPRC_BLOCKED));
 4265 
 4266         (op)(m);
 4267 
 4268         /*
 4269          * If the object is read-locked, new wirings may be created via an
 4270          * object lookup.
 4271          */
 4272         old = vm_page_drop(m, VPRC_BLOCKED);
 4273         KASSERT(!VM_OBJECT_WOWNED(m->object) ||
 4274             old == (VPRC_BLOCKED | VPRC_OBJREF),
 4275             ("vm_page_try_blocked_op: unexpected refcount value %u for %p",
 4276             old, m));
 4277         return (true);
 4278 }
 4279 
 4280 /*
 4281  * Atomically check for wirings and remove all mappings of the page.
 4282  */
 4283 bool
 4284 vm_page_try_remove_all(vm_page_t m)
 4285 {
 4286 
 4287         return (vm_page_try_blocked_op(m, pmap_remove_all));
 4288 }
 4289 
 4290 /*
 4291  * Atomically check for wirings and remove all writeable mappings of the page.
 4292  */
 4293 bool
 4294 vm_page_try_remove_write(vm_page_t m)
 4295 {
 4296 
 4297         return (vm_page_try_blocked_op(m, pmap_remove_write));
 4298 }
 4299 
 4300 /*
 4301  * vm_page_advise
 4302  *
 4303  *      Apply the specified advice to the given page.
 4304  */
 4305 void
 4306 vm_page_advise(vm_page_t m, int advice)
 4307 {
 4308 
 4309         VM_OBJECT_ASSERT_WLOCKED(m->object);
 4310         vm_page_assert_xbusied(m);
 4311 
 4312         if (advice == MADV_FREE)
 4313                 /*
 4314                  * Mark the page clean.  This will allow the page to be freed
 4315                  * without first paging it out.  MADV_FREE pages are often
 4316                  * quickly reused by malloc(3), so we do not do anything that
 4317                  * would result in a page fault on a later access.
 4318                  */
 4319                 vm_page_undirty(m);
 4320         else if (advice != MADV_DONTNEED) {
 4321                 if (advice == MADV_WILLNEED)
 4322                         vm_page_activate(m);
 4323                 return;
 4324         }
 4325 
 4326         if (advice != MADV_FREE && m->dirty == 0 && pmap_is_modified(m))
 4327                 vm_page_dirty(m);
 4328 
 4329         /*
 4330          * Clear any references to the page.  Otherwise, the page daemon will
 4331          * immediately reactivate the page.
 4332          */
 4333         vm_page_aflag_clear(m, PGA_REFERENCED);
 4334 
 4335         /*
 4336          * Place clean pages near the head of the inactive queue rather than
 4337          * the tail, thus defeating the queue's LRU operation and ensuring that
 4338          * the page will be reused quickly.  Dirty pages not already in the
 4339          * laundry are moved there.
 4340          */
 4341         if (m->dirty == 0)
 4342                 vm_page_deactivate_noreuse(m);
 4343         else if (!vm_page_in_laundry(m))
 4344                 vm_page_launder(m);
 4345 }
 4346 
 4347 /*
 4348  *      vm_page_grab_release
 4349  *
 4350  *      Helper routine for grab functions to release busy on return.
 4351  */
 4352 static inline void
 4353 vm_page_grab_release(vm_page_t m, int allocflags)
 4354 {
 4355 
 4356         if ((allocflags & VM_ALLOC_NOBUSY) != 0) {
 4357                 if ((allocflags & VM_ALLOC_IGN_SBUSY) != 0)
 4358                         vm_page_sunbusy(m);
 4359                 else
 4360                         vm_page_xunbusy(m);
 4361         }
 4362 }
 4363 
 4364 /*
 4365  *      vm_page_grab_sleep
 4366  *
 4367  *      Sleep for busy according to VM_ALLOC_ parameters.  Returns true
 4368  *      if the caller should retry and false otherwise.
 4369  *
 4370  *      If the object is locked on entry the object will be unlocked with
 4371  *      false returns and still locked but possibly having been dropped
 4372  *      with true returns.
 4373  */
 4374 static bool
 4375 vm_page_grab_sleep(vm_object_t object, vm_page_t m, vm_pindex_t pindex,
 4376     const char *wmesg, int allocflags, bool locked)
 4377 {
 4378 
 4379         if ((allocflags & VM_ALLOC_NOWAIT) != 0)
 4380                 return (false);
 4381 
 4382         /*
 4383          * Reference the page before unlocking and sleeping so that
 4384          * the page daemon is less likely to reclaim it.
 4385          */
 4386         if (locked && (allocflags & VM_ALLOC_NOCREAT) == 0)
 4387                 vm_page_reference(m);
 4388 
 4389         if (_vm_page_busy_sleep(object, m, pindex, wmesg, allocflags, locked) &&
 4390             locked)
 4391                 VM_OBJECT_WLOCK(object);
 4392         if ((allocflags & VM_ALLOC_WAITFAIL) != 0)
 4393                 return (false);
 4394 
 4395         return (true);
 4396 }
 4397 
 4398 /*
 4399  * Assert that the grab flags are valid.
 4400  */
 4401 static inline void
 4402 vm_page_grab_check(int allocflags)
 4403 {
 4404 
 4405         KASSERT((allocflags & VM_ALLOC_NOBUSY) == 0 ||
 4406             (allocflags & VM_ALLOC_WIRED) != 0,
 4407             ("vm_page_grab*: the pages must be busied or wired"));
 4408 
 4409         KASSERT((allocflags & VM_ALLOC_SBUSY) == 0 ||
 4410             (allocflags & VM_ALLOC_IGN_SBUSY) != 0,
 4411             ("vm_page_grab*: VM_ALLOC_SBUSY/VM_ALLOC_IGN_SBUSY mismatch"));
 4412 }
 4413 
 4414 /*
 4415  * Calculate the page allocation flags for grab.
 4416  */
 4417 static inline int
 4418 vm_page_grab_pflags(int allocflags)
 4419 {
 4420         int pflags;
 4421 
 4422         pflags = allocflags &
 4423             ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL |
 4424             VM_ALLOC_NOBUSY);
 4425         if ((allocflags & VM_ALLOC_NOWAIT) == 0)
 4426                 pflags |= VM_ALLOC_WAITFAIL;
 4427         if ((allocflags & VM_ALLOC_IGN_SBUSY) != 0)
 4428                 pflags |= VM_ALLOC_SBUSY;
 4429 
 4430         return (pflags);
 4431 }
 4432 
 4433 /*
 4434  * Grab a page, waiting until we are waken up due to the page
 4435  * changing state.  We keep on waiting, if the page continues
 4436  * to be in the object.  If the page doesn't exist, first allocate it
 4437  * and then conditionally zero it.
 4438  *
 4439  * This routine may sleep.
 4440  *
 4441  * The object must be locked on entry.  The lock will, however, be released
 4442  * and reacquired if the routine sleeps.
 4443  */
 4444 vm_page_t
 4445 vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
 4446 {
 4447         vm_page_t m;
 4448 
 4449         VM_OBJECT_ASSERT_WLOCKED(object);
 4450         vm_page_grab_check(allocflags);
 4451 
 4452 retrylookup:
 4453         if ((m = vm_page_lookup(object, pindex)) != NULL) {
 4454                 if (!vm_page_tryacquire(m, allocflags)) {
 4455                         if (vm_page_grab_sleep(object, m, pindex, "pgrbwt",
 4456                             allocflags, true))
 4457                                 goto retrylookup;
 4458                         return (NULL);
 4459                 }
 4460                 goto out;
 4461         }
 4462         if ((allocflags & VM_ALLOC_NOCREAT) != 0)
 4463                 return (NULL);
 4464         m = vm_page_alloc(object, pindex, vm_page_grab_pflags(allocflags));
 4465         if (m == NULL) {
 4466                 if ((allocflags & (VM_ALLOC_NOWAIT | VM_ALLOC_WAITFAIL)) != 0)
 4467                         return (NULL);
 4468                 goto retrylookup;
 4469         }
 4470         if (allocflags & VM_ALLOC_ZERO && (m->flags & PG_ZERO) == 0)
 4471                 pmap_zero_page(m);
 4472 
 4473 out:
 4474         vm_page_grab_release(m, allocflags);
 4475 
 4476         return (m);
 4477 }
 4478 
 4479 /*
 4480  * Locklessly attempt to acquire a page given a (object, pindex) tuple
 4481  * and an optional previous page to avoid the radix lookup.  The resulting
 4482  * page will be validated against the identity tuple and busied or wired
 4483  * as requested.  A NULL *mp return guarantees that the page was not in
 4484  * radix at the time of the call but callers must perform higher level
 4485  * synchronization or retry the operation under a lock if they require
 4486  * an atomic answer.  This is the only lock free validation routine,
 4487  * other routines can depend on the resulting page state.
 4488  *
 4489  * The return value indicates whether the operation failed due to caller
 4490  * flags.  The return is tri-state with mp:
 4491  *
 4492  * (true, *mp != NULL) - The operation was successful.
 4493  * (true, *mp == NULL) - The page was not found in tree.
 4494  * (false, *mp == NULL) - WAITFAIL or NOWAIT prevented acquisition.
 4495  */
 4496 static bool
 4497 vm_page_acquire_unlocked(vm_object_t object, vm_pindex_t pindex,
 4498     vm_page_t prev, vm_page_t *mp, int allocflags)
 4499 {
 4500         vm_page_t m;
 4501 
 4502         vm_page_grab_check(allocflags);
 4503         MPASS(prev == NULL || vm_page_busied(prev) || vm_page_wired(prev));
 4504 
 4505         *mp = NULL;
 4506         for (;;) {
 4507                 /*
 4508                  * We may see a false NULL here because the previous page
 4509                  * has been removed or just inserted and the list is loaded
 4510                  * without barriers.  Switch to radix to verify.
 4511                  */
 4512                 if (prev == NULL || (m = TAILQ_NEXT(prev, listq)) == NULL ||
 4513                     QMD_IS_TRASHED(m) || m->pindex != pindex ||
 4514                     atomic_load_ptr(&m->object) != object) {
 4515                         prev = NULL;
 4516                         /*
 4517                          * This guarantees the result is instantaneously
 4518                          * correct.
 4519                          */
 4520                         m = vm_radix_lookup_unlocked(&object->rtree, pindex);
 4521                 }
 4522                 if (m == NULL)
 4523                         return (true);
 4524                 if (vm_page_trybusy(m, allocflags)) {
 4525                         if (m->object == object && m->pindex == pindex)
 4526                                 break;
 4527                         /* relookup. */
 4528                         vm_page_busy_release(m);
 4529                         cpu_spinwait();
 4530                         continue;
 4531                 }
 4532                 if (!vm_page_grab_sleep(object, m, pindex, "pgnslp",
 4533                     allocflags, false))
 4534                         return (false);
 4535         }
 4536         if ((allocflags & VM_ALLOC_WIRED) != 0)
 4537                 vm_page_wire(m);
 4538         vm_page_grab_release(m, allocflags);
 4539         *mp = m;
 4540         return (true);
 4541 }
 4542 
 4543 /*
 4544  * Try to locklessly grab a page and fall back to the object lock if NOCREAT
 4545  * is not set.
 4546  */
 4547 vm_page_t
 4548 vm_page_grab_unlocked(vm_object_t object, vm_pindex_t pindex, int allocflags)
 4549 {
 4550         vm_page_t m;
 4551 
 4552         vm_page_grab_check(allocflags);
 4553 
 4554         if (!vm_page_acquire_unlocked(object, pindex, NULL, &m, allocflags))
 4555                 return (NULL);
 4556         if (m != NULL)
 4557                 return (m);
 4558 
 4559         /*
 4560          * The radix lockless lookup should never return a false negative
 4561          * errors.  If the user specifies NOCREAT they are guaranteed there
 4562          * was no page present at the instant of the call.  A NOCREAT caller
 4563          * must handle create races gracefully.
 4564          */
 4565         if ((allocflags & VM_ALLOC_NOCREAT) != 0)
 4566                 return (NULL);
 4567 
 4568         VM_OBJECT_WLOCK(object);
 4569         m = vm_page_grab(object, pindex, allocflags);
 4570         VM_OBJECT_WUNLOCK(object);
 4571 
 4572         return (m);
 4573 }
 4574 
 4575 /*
 4576  * Grab a page and make it valid, paging in if necessary.  Pages missing from
 4577  * their pager are zero filled and validated.  If a VM_ALLOC_COUNT is supplied
 4578  * and the page is not valid as many as VM_INITIAL_PAGEIN pages can be brought
 4579  * in simultaneously.  Additional pages will be left on a paging queue but
 4580  * will neither be wired nor busy regardless of allocflags.
 4581  */
 4582 int
 4583 vm_page_grab_valid(vm_page_t *mp, vm_object_t object, vm_pindex_t pindex, int allocflags)
 4584 {
 4585         vm_page_t m;
 4586         vm_page_t ma[VM_INITIAL_PAGEIN];
 4587         int after, i, pflags, rv;
 4588 
 4589         KASSERT((allocflags & VM_ALLOC_SBUSY) == 0 ||
 4590             (allocflags & VM_ALLOC_IGN_SBUSY) != 0,
 4591             ("vm_page_grab_valid: VM_ALLOC_SBUSY/VM_ALLOC_IGN_SBUSY mismatch"));
 4592         KASSERT((allocflags &
 4593             (VM_ALLOC_NOWAIT | VM_ALLOC_WAITFAIL | VM_ALLOC_ZERO)) == 0,
 4594             ("vm_page_grab_valid: Invalid flags 0x%X", allocflags));
 4595         VM_OBJECT_ASSERT_WLOCKED(object);
 4596         pflags = allocflags & ~(VM_ALLOC_NOBUSY | VM_ALLOC_SBUSY |
 4597             VM_ALLOC_WIRED);
 4598         pflags |= VM_ALLOC_WAITFAIL;
 4599 
 4600 retrylookup:
 4601         if ((m = vm_page_lookup(object, pindex)) != NULL) {
 4602                 /*
 4603                  * If the page is fully valid it can only become invalid
 4604                  * with the object lock held.  If it is not valid it can
 4605                  * become valid with the busy lock held.  Therefore, we
 4606                  * may unnecessarily lock the exclusive busy here if we
 4607                  * race with I/O completion not using the object lock.
 4608                  * However, we will not end up with an invalid page and a
 4609                  * shared lock.
 4610                  */
 4611                 if (!vm_page_trybusy(m,
 4612                     vm_page_all_valid(m) ? allocflags : 0)) {
 4613                         (void)vm_page_grab_sleep(object, m, pindex, "pgrbwt",
 4614                             allocflags, true);
 4615                         goto retrylookup;
 4616                 }
 4617                 if (vm_page_all_valid(m))
 4618                         goto out;
 4619                 if ((allocflags & VM_ALLOC_NOCREAT) != 0) {
 4620                         vm_page_busy_release(m);
 4621                         *mp = NULL;
 4622                         return (VM_PAGER_FAIL);
 4623                 }
 4624         } else if ((allocflags & VM_ALLOC_NOCREAT) != 0) {
 4625                 *mp = NULL;
 4626                 return (VM_PAGER_FAIL);
 4627         } else if ((m = vm_page_alloc(object, pindex, pflags)) == NULL) {
 4628                 goto retrylookup;
 4629         }
 4630 
 4631         vm_page_assert_xbusied(m);
 4632         if (vm_pager_has_page(object, pindex, NULL, &after)) {
 4633                 after = MIN(after, VM_INITIAL_PAGEIN);
 4634                 after = MIN(after, allocflags >> VM_ALLOC_COUNT_SHIFT);
 4635                 after = MAX(after, 1);
 4636                 ma[0] = m;
 4637                 for (i = 1; i < after; i++) {
 4638                         if ((ma[i] = vm_page_next(ma[i - 1])) != NULL) {
 4639                                 if (ma[i]->valid || !vm_page_tryxbusy(ma[i]))
 4640                                         break;
 4641                         } else {
 4642                                 ma[i] = vm_page_alloc(object, m->pindex + i,
 4643                                     VM_ALLOC_NORMAL);
 4644                                 if (ma[i] == NULL)
 4645                                         break;
 4646                         }
 4647                 }
 4648                 after = i;
 4649                 vm_object_pip_add(object, after);
 4650                 VM_OBJECT_WUNLOCK(object);
 4651                 rv = vm_pager_get_pages(object, ma, after, NULL, NULL);
 4652                 VM_OBJECT_WLOCK(object);
 4653                 vm_object_pip_wakeupn(object, after);
 4654                 /* Pager may have replaced a page. */
 4655                 m = ma[0];
 4656                 if (rv != VM_PAGER_OK) {
 4657                         for (i = 0; i < after; i++) {
 4658                                 if (!vm_page_wired(ma[i]))
 4659                                         vm_page_free(ma[i]);
 4660                                 else
 4661                                         vm_page_xunbusy(ma[i]);
 4662                         }
 4663                         *mp = NULL;
 4664                         return (rv);
 4665                 }
 4666                 for (i = 1; i < after; i++)
 4667                         vm_page_readahead_finish(ma[i]);
 4668                 MPASS(vm_page_all_valid(m));
 4669         } else {
 4670                 vm_page_zero_invalid(m, TRUE);
 4671         }
 4672 out:
 4673         if ((allocflags & VM_ALLOC_WIRED) != 0)
 4674                 vm_page_wire(m);
 4675         if ((allocflags & VM_ALLOC_SBUSY) != 0 && vm_page_xbusied(m))
 4676                 vm_page_busy_downgrade(m);
 4677         else if ((allocflags & VM_ALLOC_NOBUSY) != 0)
 4678                 vm_page_busy_release(m);
 4679         *mp = m;
 4680         return (VM_PAGER_OK);
 4681 }
 4682 
 4683 /*
 4684  * Locklessly grab a valid page.  If the page is not valid or not yet
 4685  * allocated this will fall back to the object lock method.
 4686  */
 4687 int
 4688 vm_page_grab_valid_unlocked(vm_page_t *mp, vm_object_t object,
 4689     vm_pindex_t pindex, int allocflags)
 4690 {
 4691         vm_page_t m;
 4692         int flags;
 4693         int error;
 4694 
 4695         KASSERT((allocflags & VM_ALLOC_SBUSY) == 0 ||
 4696             (allocflags & VM_ALLOC_IGN_SBUSY) != 0,
 4697             ("vm_page_grab_valid_unlocked: VM_ALLOC_SBUSY/VM_ALLOC_IGN_SBUSY "
 4698             "mismatch"));
 4699         KASSERT((allocflags &
 4700             (VM_ALLOC_NOWAIT | VM_ALLOC_WAITFAIL | VM_ALLOC_ZERO)) == 0,
 4701             ("vm_page_grab_valid_unlocked: Invalid flags 0x%X", allocflags));
 4702 
 4703         /*
 4704          * Attempt a lockless lookup and busy.  We need at least an sbusy
 4705          * before we can inspect the valid field and return a wired page.
 4706          */
 4707         flags = allocflags & ~(VM_ALLOC_NOBUSY | VM_ALLOC_WIRED);
 4708         if (!vm_page_acquire_unlocked(object, pindex, NULL, mp, flags))
 4709                 return (VM_PAGER_FAIL);
 4710         if ((m = *mp) != NULL) {
 4711                 if (vm_page_all_valid(m)) {
 4712                         if ((allocflags & VM_ALLOC_WIRED) != 0)
 4713                                 vm_page_wire(m);
 4714                         vm_page_grab_release(m, allocflags);
 4715                         return (VM_PAGER_OK);
 4716                 }
 4717                 vm_page_busy_release(m);
 4718         }
 4719         if ((allocflags & VM_ALLOC_NOCREAT) != 0) {
 4720                 *mp = NULL;
 4721                 return (VM_PAGER_FAIL);
 4722         }
 4723         VM_OBJECT_WLOCK(object);
 4724         error = vm_page_grab_valid(mp, object, pindex, allocflags);
 4725         VM_OBJECT_WUNLOCK(object);
 4726 
 4727         return (error);
 4728 }
 4729 
 4730 /*
 4731  * Return the specified range of pages from the given object.  For each
 4732  * page offset within the range, if a page already exists within the object
 4733  * at that offset and it is busy, then wait for it to change state.  If,
 4734  * instead, the page doesn't exist, then allocate it.
 4735  *
 4736  * The caller must always specify an allocation class.
 4737  *
 4738  * allocation classes:
 4739  *      VM_ALLOC_NORMAL         normal process request
 4740  *      VM_ALLOC_SYSTEM         system *really* needs the pages
 4741  *
 4742  * The caller must always specify that the pages are to be busied and/or
 4743  * wired.
 4744  *
 4745  * optional allocation flags:
 4746  *      VM_ALLOC_IGN_SBUSY      do not sleep on soft busy pages
 4747  *      VM_ALLOC_NOBUSY         do not exclusive busy the page
 4748  *      VM_ALLOC_NOWAIT         do not sleep
 4749  *      VM_ALLOC_SBUSY          set page to sbusy state
 4750  *      VM_ALLOC_WIRED          wire the pages
 4751  *      VM_ALLOC_ZERO           zero and validate any invalid pages
 4752  *
 4753  * If VM_ALLOC_NOWAIT is not specified, this routine may sleep.  Otherwise, it
 4754  * may return a partial prefix of the requested range.
 4755  */
 4756 int
 4757 vm_page_grab_pages(vm_object_t object, vm_pindex_t pindex, int allocflags,
 4758     vm_page_t *ma, int count)
 4759 {
 4760         vm_page_t m, mpred;
 4761         int pflags;
 4762         int i;
 4763 
 4764         VM_OBJECT_ASSERT_WLOCKED(object);
 4765         KASSERT(((u_int)allocflags >> VM_ALLOC_COUNT_SHIFT) == 0,
 4766             ("vm_page_grap_pages: VM_ALLOC_COUNT() is not allowed"));
 4767         KASSERT(count > 0,
 4768             ("vm_page_grab_pages: invalid page count %d", count));
 4769         vm_page_grab_check(allocflags);
 4770 
 4771         pflags = vm_page_grab_pflags(allocflags);
 4772         i = 0;
 4773 retrylookup:
 4774         m = vm_radix_lookup_le(&object->rtree, pindex + i);
 4775         if (m == NULL || m->pindex != pindex + i) {
 4776                 mpred = m;
 4777                 m = NULL;
 4778         } else
 4779                 mpred = TAILQ_PREV(m, pglist, listq);
 4780         for (; i < count; i++) {
 4781                 if (m != NULL) {
 4782                         if (!vm_page_tryacquire(m, allocflags)) {
 4783                                 if (vm_page_grab_sleep(object, m, pindex + i,
 4784                                     "grbmaw", allocflags, true))
 4785                                         goto retrylookup;
 4786                                 break;
 4787                         }
 4788                 } else {
 4789                         if ((allocflags & VM_ALLOC_NOCREAT) != 0)
 4790                                 break;
 4791                         m = vm_page_alloc_after(object, pindex + i,
 4792                             pflags | VM_ALLOC_COUNT(count - i), mpred);
 4793                         if (m == NULL) {
 4794                                 if ((allocflags & (VM_ALLOC_NOWAIT |
 4795                                     VM_ALLOC_WAITFAIL)) != 0)
 4796                                         break;
 4797                                 goto retrylookup;
 4798                         }
 4799                 }
 4800                 if (vm_page_none_valid(m) &&
 4801                     (allocflags & VM_ALLOC_ZERO) != 0) {
 4802                         if ((m->flags & PG_ZERO) == 0)
 4803                                 pmap_zero_page(m);
 4804                         vm_page_valid(m);
 4805                 }
 4806                 vm_page_grab_release(m, allocflags);
 4807                 ma[i] = mpred = m;
 4808                 m = vm_page_next(m);
 4809         }
 4810         return (i);
 4811 }
 4812 
 4813 /*
 4814  * Unlocked variant of vm_page_grab_pages().  This accepts the same flags
 4815  * and will fall back to the locked variant to handle allocation.
 4816  */
 4817 int
 4818 vm_page_grab_pages_unlocked(vm_object_t object, vm_pindex_t pindex,
 4819     int allocflags, vm_page_t *ma, int count)
 4820 {
 4821         vm_page_t m, pred;
 4822         int flags;
 4823         int i;
 4824 
 4825         KASSERT(count > 0,
 4826             ("vm_page_grab_pages_unlocked: invalid page count %d", count));
 4827         vm_page_grab_check(allocflags);
 4828 
 4829         /*
 4830          * Modify flags for lockless acquire to hold the page until we
 4831          * set it valid if necessary.
 4832          */
 4833         flags = allocflags & ~VM_ALLOC_NOBUSY;
 4834         pred = NULL;
 4835         for (i = 0; i < count; i++, pindex++) {
 4836                 if (!vm_page_acquire_unlocked(object, pindex, pred, &m, flags))
 4837                         return (i);
 4838                 if (m == NULL)
 4839                         break;
 4840                 if ((flags & VM_ALLOC_ZERO) != 0 && vm_page_none_valid(m)) {
 4841                         if ((m->flags & PG_ZERO) == 0)
 4842                                 pmap_zero_page(m);
 4843                         vm_page_valid(m);
 4844                 }
 4845                 /* m will still be wired or busy according to flags. */
 4846                 vm_page_grab_release(m, allocflags);
 4847                 pred = ma[i] = m;
 4848         }
 4849         if (i == count || (allocflags & VM_ALLOC_NOCREAT) != 0)
 4850                 return (i);
 4851         count -= i;
 4852         VM_OBJECT_WLOCK(object);
 4853         i += vm_page_grab_pages(object, pindex, allocflags, &ma[i], count);
 4854         VM_OBJECT_WUNLOCK(object);
 4855 
 4856         return (i);
 4857 }
 4858 
 4859 /*
 4860  * Mapping function for valid or dirty bits in a page.
 4861  *
 4862  * Inputs are required to range within a page.
 4863  */
 4864 vm_page_bits_t
 4865 vm_page_bits(int base, int size)
 4866 {
 4867         int first_bit;
 4868         int last_bit;
 4869 
 4870         KASSERT(
 4871             base + size <= PAGE_SIZE,
 4872             ("vm_page_bits: illegal base/size %d/%d", base, size)
 4873         );
 4874 
 4875         if (size == 0)          /* handle degenerate case */
 4876                 return (0);
 4877 
 4878         first_bit = base >> DEV_BSHIFT;
 4879         last_bit = (base + size - 1) >> DEV_BSHIFT;
 4880 
 4881         return (((vm_page_bits_t)2 << last_bit) -
 4882             ((vm_page_bits_t)1 << first_bit));
 4883 }
 4884 
 4885 void
 4886 vm_page_bits_set(vm_page_t m, vm_page_bits_t *bits, vm_page_bits_t set)
 4887 {
 4888 
 4889 #if PAGE_SIZE == 32768
 4890         atomic_set_64((uint64_t *)bits, set);
 4891 #elif PAGE_SIZE == 16384
 4892         atomic_set_32((uint32_t *)bits, set);
 4893 #elif (PAGE_SIZE == 8192) && defined(atomic_set_16)
 4894         atomic_set_16((uint16_t *)bits, set);
 4895 #elif (PAGE_SIZE == 4096) && defined(atomic_set_8)
 4896         atomic_set_8((uint8_t *)bits, set);
 4897 #else           /* PAGE_SIZE <= 8192 */
 4898         uintptr_t addr;
 4899         int shift;
 4900 
 4901         addr = (uintptr_t)bits;
 4902         /*
 4903          * Use a trick to perform a 32-bit atomic on the
 4904          * containing aligned word, to not depend on the existence
 4905          * of atomic_{set, clear}_{8, 16}.
 4906          */
 4907         shift = addr & (sizeof(uint32_t) - 1);
 4908 #if BYTE_ORDER == BIG_ENDIAN
 4909         shift = (sizeof(uint32_t) - sizeof(vm_page_bits_t) - shift) * NBBY;
 4910 #else
 4911         shift *= NBBY;
 4912 #endif
 4913         addr &= ~(sizeof(uint32_t) - 1);
 4914         atomic_set_32((uint32_t *)addr, set << shift);
 4915 #endif          /* PAGE_SIZE */
 4916 }
 4917 
 4918 static inline void
 4919 vm_page_bits_clear(vm_page_t m, vm_page_bits_t *bits, vm_page_bits_t clear)
 4920 {
 4921 
 4922 #if PAGE_SIZE == 32768
 4923         atomic_clear_64((uint64_t *)bits, clear);
 4924 #elif PAGE_SIZE == 16384
 4925         atomic_clear_32((uint32_t *)bits, clear);
 4926 #elif (PAGE_SIZE == 8192) && defined(atomic_clear_16)
 4927         atomic_clear_16((uint16_t *)bits, clear);
 4928 #elif (PAGE_SIZE == 4096) && defined(atomic_clear_8)
 4929         atomic_clear_8((uint8_t *)bits, clear);
 4930 #else           /* PAGE_SIZE <= 8192 */
 4931         uintptr_t addr;
 4932         int shift;
 4933 
 4934         addr = (uintptr_t)bits;
 4935         /*
 4936          * Use a trick to perform a 32-bit atomic on the
 4937          * containing aligned word, to not depend on the existence
 4938          * of atomic_{set, clear}_{8, 16}.
 4939          */
 4940         shift = addr & (sizeof(uint32_t) - 1);
 4941 #if BYTE_ORDER == BIG_ENDIAN
 4942         shift = (sizeof(uint32_t) - sizeof(vm_page_bits_t) - shift) * NBBY;
 4943 #else
 4944         shift *= NBBY;
 4945 #endif
 4946         addr &= ~(sizeof(uint32_t) - 1);
 4947         atomic_clear_32((uint32_t *)addr, clear << shift);
 4948 #endif          /* PAGE_SIZE */
 4949 }
 4950 
 4951 static inline vm_page_bits_t
 4952 vm_page_bits_swap(vm_page_t m, vm_page_bits_t *bits, vm_page_bits_t newbits)
 4953 {
 4954 #if PAGE_SIZE == 32768
 4955         uint64_t old;
 4956 
 4957         old = *bits;
 4958         while (atomic_fcmpset_64(bits, &old, newbits) == 0);
 4959         return (old);
 4960 #elif PAGE_SIZE == 16384
 4961         uint32_t old;
 4962 
 4963         old = *bits;
 4964         while (atomic_fcmpset_32(bits, &old, newbits) == 0);
 4965         return (old);
 4966 #elif (PAGE_SIZE == 8192) && defined(atomic_fcmpset_16)
 4967         uint16_t old;
 4968 
 4969         old = *bits;
 4970         while (atomic_fcmpset_16(bits, &old, newbits) == 0);
 4971         return (old);
 4972 #elif (PAGE_SIZE == 4096) && defined(atomic_fcmpset_8)
 4973         uint8_t old;
 4974 
 4975         old = *bits;
 4976         while (atomic_fcmpset_8(bits, &old, newbits) == 0);
 4977         return (old);
 4978 #else           /* PAGE_SIZE <= 4096*/
 4979         uintptr_t addr;
 4980         uint32_t old, new, mask;
 4981         int shift;
 4982 
 4983         addr = (uintptr_t)bits;
 4984         /*
 4985          * Use a trick to perform a 32-bit atomic on the
 4986          * containing aligned word, to not depend on the existence
 4987          * of atomic_{set, swap, clear}_{8, 16}.
 4988          */
 4989         shift = addr & (sizeof(uint32_t) - 1);
 4990 #if BYTE_ORDER == BIG_ENDIAN
 4991         shift = (sizeof(uint32_t) - sizeof(vm_page_bits_t) - shift) * NBBY;
 4992 #else
 4993         shift *= NBBY;
 4994 #endif
 4995         addr &= ~(sizeof(uint32_t) - 1);
 4996         mask = VM_PAGE_BITS_ALL << shift;
 4997 
 4998         old = *bits;
 4999         do {
 5000                 new = old & ~mask;
 5001                 new |= newbits << shift;
 5002         } while (atomic_fcmpset_32((uint32_t *)addr, &old, new) == 0);
 5003         return (old >> shift);
 5004 #endif          /* PAGE_SIZE */
 5005 }
 5006 
 5007 /*
 5008  *      vm_page_set_valid_range:
 5009  *
 5010  *      Sets portions of a page valid.  The arguments are expected
 5011  *      to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
 5012  *      of any partial chunks touched by the range.  The invalid portion of
 5013  *      such chunks will be zeroed.
 5014  *
 5015  *      (base + size) must be less then or equal to PAGE_SIZE.
 5016  */
 5017 void
 5018 vm_page_set_valid_range(vm_page_t m, int base, int size)
 5019 {
 5020         int endoff, frag;
 5021         vm_page_bits_t pagebits;
 5022 
 5023         vm_page_assert_busied(m);
 5024         if (size == 0)  /* handle degenerate case */
 5025                 return;
 5026 
 5027         /*
 5028          * If the base is not DEV_BSIZE aligned and the valid
 5029          * bit is clear, we have to zero out a portion of the
 5030          * first block.
 5031          */
 5032         if ((frag = rounddown2(base, DEV_BSIZE)) != base &&
 5033             (m->valid & (1 << (base >> DEV_BSHIFT))) == 0)
 5034                 pmap_zero_page_area(m, frag, base - frag);
 5035 
 5036         /*
 5037          * If the ending offset is not DEV_BSIZE aligned and the
 5038          * valid bit is clear, we have to zero out a portion of
 5039          * the last block.
 5040          */
 5041         endoff = base + size;
 5042         if ((frag = rounddown2(endoff, DEV_BSIZE)) != endoff &&
 5043             (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0)
 5044                 pmap_zero_page_area(m, endoff,
 5045                     DEV_BSIZE - (endoff & (DEV_BSIZE - 1)));
 5046 
 5047         /*
 5048          * Assert that no previously invalid block that is now being validated
 5049          * is already dirty.
 5050          */
 5051         KASSERT((~m->valid & vm_page_bits(base, size) & m->dirty) == 0,
 5052             ("vm_page_set_valid_range: page %p is dirty", m));
 5053 
 5054         /*
 5055          * Set valid bits inclusive of any overlap.
 5056          */
 5057         pagebits = vm_page_bits(base, size);
 5058         if (vm_page_xbusied(m))
 5059                 m->valid |= pagebits;
 5060         else
 5061                 vm_page_bits_set(m, &m->valid, pagebits);
 5062 }
 5063 
 5064 /*
 5065  * Set the page dirty bits and free the invalid swap space if
 5066  * present.  Returns the previous dirty bits.
 5067  */
 5068 vm_page_bits_t
 5069 vm_page_set_dirty(vm_page_t m)
 5070 {
 5071         vm_page_bits_t old;
 5072 
 5073         VM_PAGE_OBJECT_BUSY_ASSERT(m);
 5074 
 5075         if (vm_page_xbusied(m) && !pmap_page_is_write_mapped(m)) {
 5076                 old = m->dirty;
 5077                 m->dirty = VM_PAGE_BITS_ALL;
 5078         } else
 5079                 old = vm_page_bits_swap(m, &m->dirty, VM_PAGE_BITS_ALL);
 5080         if (old == 0 && (m->a.flags & PGA_SWAP_SPACE) != 0)
 5081                 vm_pager_page_unswapped(m);
 5082 
 5083         return (old);
 5084 }
 5085 
 5086 /*
 5087  * Clear the given bits from the specified page's dirty field.
 5088  */
 5089 static __inline void
 5090 vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits)
 5091 {
 5092 
 5093         vm_page_assert_busied(m);
 5094 
 5095         /*
 5096          * If the page is xbusied and not write mapped we are the
 5097          * only thread that can modify dirty bits.  Otherwise, The pmap
 5098          * layer can call vm_page_dirty() without holding a distinguished
 5099          * lock.  The combination of page busy and atomic operations
 5100          * suffice to guarantee consistency of the page dirty field.
 5101          */
 5102         if (vm_page_xbusied(m) && !pmap_page_is_write_mapped(m))
 5103                 m->dirty &= ~pagebits;
 5104         else
 5105                 vm_page_bits_clear(m, &m->dirty, pagebits);
 5106 }
 5107 
 5108 /*
 5109  *      vm_page_set_validclean:
 5110  *
 5111  *      Sets portions of a page valid and clean.  The arguments are expected
 5112  *      to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
 5113  *      of any partial chunks touched by the range.  The invalid portion of
 5114  *      such chunks will be zero'd.
 5115  *
 5116  *      (base + size) must be less then or equal to PAGE_SIZE.
 5117  */
 5118 void
 5119 vm_page_set_validclean(vm_page_t m, int base, int size)
 5120 {
 5121         vm_page_bits_t oldvalid, pagebits;
 5122         int endoff, frag;
 5123 
 5124         vm_page_assert_busied(m);
 5125         if (size == 0)  /* handle degenerate case */
 5126                 return;
 5127 
 5128         /*
 5129          * If the base is not DEV_BSIZE aligned and the valid
 5130          * bit is clear, we have to zero out a portion of the
 5131          * first block.
 5132          */
 5133         if ((frag = rounddown2(base, DEV_BSIZE)) != base &&
 5134             (m->valid & ((vm_page_bits_t)1 << (base >> DEV_BSHIFT))) == 0)
 5135                 pmap_zero_page_area(m, frag, base - frag);
 5136 
 5137         /*
 5138          * If the ending offset is not DEV_BSIZE aligned and the
 5139          * valid bit is clear, we have to zero out a portion of
 5140          * the last block.
 5141          */
 5142         endoff = base + size;
 5143         if ((frag = rounddown2(endoff, DEV_BSIZE)) != endoff &&
 5144             (m->valid & ((vm_page_bits_t)1 << (endoff >> DEV_BSHIFT))) == 0)
 5145                 pmap_zero_page_area(m, endoff,
 5146                     DEV_BSIZE - (endoff & (DEV_BSIZE - 1)));
 5147 
 5148         /*
 5149          * Set valid, clear dirty bits.  If validating the entire
 5150          * page we can safely clear the pmap modify bit.  We also
 5151          * use this opportunity to clear the PGA_NOSYNC flag.  If a process
 5152          * takes a write fault on a MAP_NOSYNC memory area the flag will
 5153          * be set again.
 5154          *
 5155          * We set valid bits inclusive of any overlap, but we can only
 5156          * clear dirty bits for DEV_BSIZE chunks that are fully within
 5157          * the range.
 5158          */
 5159         oldvalid = m->valid;
 5160         pagebits = vm_page_bits(base, size);
 5161         if (vm_page_xbusied(m))
 5162                 m->valid |= pagebits;
 5163         else
 5164                 vm_page_bits_set(m, &m->valid, pagebits);
 5165 #if 0   /* NOT YET */
 5166         if ((frag = base & (DEV_BSIZE - 1)) != 0) {
 5167                 frag = DEV_BSIZE - frag;
 5168                 base += frag;
 5169                 size -= frag;
 5170                 if (size < 0)
 5171                         size = 0;
 5172         }
 5173         pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1));
 5174 #endif
 5175         if (base == 0 && size == PAGE_SIZE) {
 5176                 /*
 5177                  * The page can only be modified within the pmap if it is
 5178                  * mapped, and it can only be mapped if it was previously
 5179                  * fully valid.
 5180                  */
 5181                 if (oldvalid == VM_PAGE_BITS_ALL)
 5182                         /*
 5183                          * Perform the pmap_clear_modify() first.  Otherwise,
 5184                          * a concurrent pmap operation, such as
 5185                          * pmap_protect(), could clear a modification in the
 5186                          * pmap and set the dirty field on the page before
 5187                          * pmap_clear_modify() had begun and after the dirty
 5188                          * field was cleared here.
 5189                          */
 5190                         pmap_clear_modify(m);
 5191                 m->dirty = 0;
 5192                 vm_page_aflag_clear(m, PGA_NOSYNC);
 5193         } else if (oldvalid != VM_PAGE_BITS_ALL && vm_page_xbusied(m))
 5194                 m->dirty &= ~pagebits;
 5195         else
 5196                 vm_page_clear_dirty_mask(m, pagebits);
 5197 }
 5198 
 5199 void
 5200 vm_page_clear_dirty(vm_page_t m, int base, int size)
 5201 {
 5202 
 5203         vm_page_clear_dirty_mask(m, vm_page_bits(base, size));
 5204 }
 5205 
 5206 /*
 5207  *      vm_page_set_invalid:
 5208  *
 5209  *      Invalidates DEV_BSIZE'd chunks within a page.  Both the
 5210  *      valid and dirty bits for the effected areas are cleared.
 5211  */
 5212 void
 5213 vm_page_set_invalid(vm_page_t m, int base, int size)
 5214 {
 5215         vm_page_bits_t bits;
 5216         vm_object_t object;
 5217 
 5218         /*
 5219          * The object lock is required so that pages can't be mapped
 5220          * read-only while we're in the process of invalidating them.
 5221          */
 5222         object = m->object;
 5223         VM_OBJECT_ASSERT_WLOCKED(object);
 5224         vm_page_assert_busied(m);
 5225 
 5226         if (object->type == OBJT_VNODE && base == 0 && IDX_TO_OFF(m->pindex) +
 5227             size >= object->un_pager.vnp.vnp_size)
 5228                 bits = VM_PAGE_BITS_ALL;
 5229         else
 5230                 bits = vm_page_bits(base, size);
 5231         if (object->ref_count != 0 && vm_page_all_valid(m) && bits != 0)
 5232                 pmap_remove_all(m);
 5233         KASSERT((bits == 0 && vm_page_all_valid(m)) ||
 5234             !pmap_page_is_mapped(m),
 5235             ("vm_page_set_invalid: page %p is mapped", m));
 5236         if (vm_page_xbusied(m)) {
 5237                 m->valid &= ~bits;
 5238                 m->dirty &= ~bits;
 5239         } else {
 5240                 vm_page_bits_clear(m, &m->valid, bits);
 5241                 vm_page_bits_clear(m, &m->dirty, bits);
 5242         }
 5243 }
 5244 
 5245 /*
 5246  *      vm_page_invalid:
 5247  *
 5248  *      Invalidates the entire page.  The page must be busy, unmapped, and
 5249  *      the enclosing object must be locked.  The object locks protects
 5250  *      against concurrent read-only pmap enter which is done without
 5251  *      busy.
 5252  */
 5253 void
 5254 vm_page_invalid(vm_page_t m)
 5255 {
 5256 
 5257         vm_page_assert_busied(m);
 5258         VM_OBJECT_ASSERT_LOCKED(m->object);
 5259         MPASS(!pmap_page_is_mapped(m));
 5260 
 5261         if (vm_page_xbusied(m))
 5262                 m->valid = 0;
 5263         else
 5264                 vm_page_bits_clear(m, &m->valid, VM_PAGE_BITS_ALL);
 5265 }
 5266 
 5267 /*
 5268  * vm_page_zero_invalid()
 5269  *
 5270  *      The kernel assumes that the invalid portions of a page contain
 5271  *      garbage, but such pages can be mapped into memory by user code.
 5272  *      When this occurs, we must zero out the non-valid portions of the
 5273  *      page so user code sees what it expects.
 5274  *
 5275  *      Pages are most often semi-valid when the end of a file is mapped
 5276  *      into memory and the file's size is not page aligned.
 5277  */
 5278 void
 5279 vm_page_zero_invalid(vm_page_t m, boolean_t setvalid)
 5280 {
 5281         int b;
 5282         int i;
 5283 
 5284         /*
 5285          * Scan the valid bits looking for invalid sections that
 5286          * must be zeroed.  Invalid sub-DEV_BSIZE'd areas ( where the
 5287          * valid bit may be set ) have already been zeroed by
 5288          * vm_page_set_validclean().
 5289          */
 5290         for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) {
 5291                 if (i == (PAGE_SIZE / DEV_BSIZE) ||
 5292                     (m->valid & ((vm_page_bits_t)1 << i))) {
 5293                         if (i > b) {
 5294                                 pmap_zero_page_area(m,
 5295                                     b << DEV_BSHIFT, (i - b) << DEV_BSHIFT);
 5296                         }
 5297                         b = i + 1;
 5298                 }
 5299         }
 5300 
 5301         /*
 5302          * setvalid is TRUE when we can safely set the zero'd areas
 5303          * as being valid.  We can do this if there are no cache consistancy
 5304          * issues.  e.g. it is ok to do with UFS, but not ok to do with NFS.
 5305          */
 5306         if (setvalid)
 5307                 vm_page_valid(m);
 5308 }
 5309 
 5310 /*
 5311  *      vm_page_is_valid:
 5312  *
 5313  *      Is (partial) page valid?  Note that the case where size == 0
 5314  *      will return FALSE in the degenerate case where the page is
 5315  *      entirely invalid, and TRUE otherwise.
 5316  *
 5317  *      Some callers envoke this routine without the busy lock held and
 5318  *      handle races via higher level locks.  Typical callers should
 5319  *      hold a busy lock to prevent invalidation.
 5320  */
 5321 int
 5322 vm_page_is_valid(vm_page_t m, int base, int size)
 5323 {
 5324         vm_page_bits_t bits;
 5325 
 5326         bits = vm_page_bits(base, size);
 5327         return (m->valid != 0 && (m->valid & bits) == bits);
 5328 }
 5329 
 5330 /*
 5331  * Returns true if all of the specified predicates are true for the entire
 5332  * (super)page and false otherwise.
 5333  */
 5334 bool
 5335 vm_page_ps_test(vm_page_t m, int flags, vm_page_t skip_m)
 5336 {
 5337         vm_object_t object;
 5338         int i, npages;
 5339 
 5340         object = m->object;
 5341         if (skip_m != NULL && skip_m->object != object)
 5342                 return (false);
 5343         VM_OBJECT_ASSERT_LOCKED(object);
 5344         npages = atop(pagesizes[m->psind]);
 5345 
 5346         /*
 5347          * The physically contiguous pages that make up a superpage, i.e., a
 5348          * page with a page size index ("psind") greater than zero, will
 5349          * occupy adjacent entries in vm_page_array[].
 5350          */
 5351         for (i = 0; i < npages; i++) {
 5352                 /* Always test object consistency, including "skip_m". */
 5353                 if (m[i].object != object)
 5354                         return (false);
 5355                 if (&m[i] == skip_m)
 5356                         continue;
 5357                 if ((flags & PS_NONE_BUSY) != 0 && vm_page_busied(&m[i]))
 5358                         return (false);
 5359                 if ((flags & PS_ALL_DIRTY) != 0) {
 5360                         /*
 5361                          * Calling vm_page_test_dirty() or pmap_is_modified()
 5362                          * might stop this case from spuriously returning
 5363                          * "false".  However, that would require a write lock
 5364                          * on the object containing "m[i]".
 5365                          */
 5366                         if (m[i].dirty != VM_PAGE_BITS_ALL)
 5367                                 return (false);
 5368                 }
 5369                 if ((flags & PS_ALL_VALID) != 0 &&
 5370                     m[i].valid != VM_PAGE_BITS_ALL)
 5371                         return (false);
 5372         }
 5373         return (true);
 5374 }
 5375 
 5376 /*
 5377  * Set the page's dirty bits if the page is modified.
 5378  */
 5379 void
 5380 vm_page_test_dirty(vm_page_t m)
 5381 {
 5382 
 5383         vm_page_assert_busied(m);
 5384         if (m->dirty != VM_PAGE_BITS_ALL && pmap_is_modified(m))
 5385                 vm_page_dirty(m);
 5386 }
 5387 
 5388 void
 5389 vm_page_valid(vm_page_t m)
 5390 {
 5391 
 5392         vm_page_assert_busied(m);
 5393         if (vm_page_xbusied(m))
 5394                 m->valid = VM_PAGE_BITS_ALL;
 5395         else
 5396                 vm_page_bits_set(m, &m->valid, VM_PAGE_BITS_ALL);
 5397 }
 5398 
 5399 void
 5400 vm_page_lock_KBI(vm_page_t m, const char *file, int line)
 5401 {
 5402 
 5403         mtx_lock_flags_(vm_page_lockptr(m), 0, file, line);
 5404 }
 5405 
 5406 void
 5407 vm_page_unlock_KBI(vm_page_t m, const char *file, int line)
 5408 {
 5409 
 5410         mtx_unlock_flags_(vm_page_lockptr(m), 0, file, line);
 5411 }
 5412 
 5413 int
 5414 vm_page_trylock_KBI(vm_page_t m, const char *file, int line)
 5415 {
 5416 
 5417         return (mtx_trylock_flags_(vm_page_lockptr(m), 0, file, line));
 5418 }
 5419 
 5420 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
 5421 void
 5422 vm_page_assert_locked_KBI(vm_page_t m, const char *file, int line)
 5423 {
 5424 
 5425         vm_page_lock_assert_KBI(m, MA_OWNED, file, line);
 5426 }
 5427 
 5428 void
 5429 vm_page_lock_assert_KBI(vm_page_t m, int a, const char *file, int line)
 5430 {
 5431 
 5432         mtx_assert_(vm_page_lockptr(m), a, file, line);
 5433 }
 5434 #endif
 5435 
 5436 #ifdef INVARIANTS
 5437 void
 5438 vm_page_object_busy_assert(vm_page_t m)
 5439 {
 5440 
 5441         /*
 5442          * Certain of the page's fields may only be modified by the
 5443          * holder of a page or object busy.
 5444          */
 5445         if (m->object != NULL && !vm_page_busied(m))
 5446                 VM_OBJECT_ASSERT_BUSY(m->object);
 5447 }
 5448 
 5449 void
 5450 vm_page_assert_pga_writeable(vm_page_t m, uint16_t bits)
 5451 {
 5452 
 5453         if ((bits & PGA_WRITEABLE) == 0)
 5454                 return;
 5455 
 5456         /*
 5457          * The PGA_WRITEABLE flag can only be set if the page is
 5458          * managed, is exclusively busied or the object is locked.
 5459          * Currently, this flag is only set by pmap_enter().
 5460          */
 5461         KASSERT((m->oflags & VPO_UNMANAGED) == 0,
 5462             ("PGA_WRITEABLE on unmanaged page"));
 5463         if (!vm_page_xbusied(m))
 5464                 VM_OBJECT_ASSERT_BUSY(m->object);
 5465 }
 5466 #endif
 5467 
 5468 #include "opt_ddb.h"
 5469 #ifdef DDB
 5470 #include <sys/kernel.h>
 5471 
 5472 #include <ddb/ddb.h>
 5473 
 5474 DB_SHOW_COMMAND(page, vm_page_print_page_info)
 5475 {
 5476 
 5477         db_printf("vm_cnt.v_free_count: %d\n", vm_free_count());
 5478         db_printf("vm_cnt.v_inactive_count: %d\n", vm_inactive_count());
 5479         db_printf("vm_cnt.v_active_count: %d\n", vm_active_count());
 5480         db_printf("vm_cnt.v_laundry_count: %d\n", vm_laundry_count());
 5481         db_printf("vm_cnt.v_wire_count: %d\n", vm_wire_count());
 5482         db_printf("vm_cnt.v_free_reserved: %d\n", vm_cnt.v_free_reserved);
 5483         db_printf("vm_cnt.v_free_min: %d\n", vm_cnt.v_free_min);
 5484         db_printf("vm_cnt.v_free_target: %d\n", vm_cnt.v_free_target);
 5485         db_printf("vm_cnt.v_inactive_target: %d\n", vm_cnt.v_inactive_target);
 5486 }
 5487 
 5488 DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info)
 5489 {
 5490         int dom;
 5491 
 5492         db_printf("pq_free %d\n", vm_free_count());
 5493         for (dom = 0; dom < vm_ndomains; dom++) {
 5494                 db_printf(
 5495     "dom %d page_cnt %d free %d pq_act %d pq_inact %d pq_laund %d pq_unsw %d\n",
 5496                     dom,
 5497                     vm_dom[dom].vmd_page_count,
 5498                     vm_dom[dom].vmd_free_count,
 5499                     vm_dom[dom].vmd_pagequeues[PQ_ACTIVE].pq_cnt,
 5500                     vm_dom[dom].vmd_pagequeues[PQ_INACTIVE].pq_cnt,
 5501                     vm_dom[dom].vmd_pagequeues[PQ_LAUNDRY].pq_cnt,
 5502                     vm_dom[dom].vmd_pagequeues[PQ_UNSWAPPABLE].pq_cnt);
 5503         }
 5504 }
 5505 
 5506 DB_SHOW_COMMAND(pginfo, vm_page_print_pginfo)
 5507 {
 5508         vm_page_t m;
 5509         boolean_t phys, virt;
 5510 
 5511         if (!have_addr) {
 5512                 db_printf("show pginfo addr\n");
 5513                 return;
 5514         }
 5515 
 5516         phys = strchr(modif, 'p') != NULL;
 5517         virt = strchr(modif, 'v') != NULL;
 5518         if (virt)
 5519                 m = PHYS_TO_VM_PAGE(pmap_kextract(addr));
 5520         else if (phys)
 5521                 m = PHYS_TO_VM_PAGE(addr);
 5522         else
 5523                 m = (vm_page_t)addr;
 5524         db_printf(
 5525     "page %p obj %p pidx 0x%jx phys 0x%jx q %d ref 0x%x\n"
 5526     "  af 0x%x of 0x%x f 0x%x act %d busy %x valid 0x%x dirty 0x%x\n",
 5527             m, m->object, (uintmax_t)m->pindex, (uintmax_t)m->phys_addr,
 5528             m->a.queue, m->ref_count, m->a.flags, m->oflags,
 5529             m->flags, m->a.act_count, m->busy_lock, m->valid, m->dirty);
 5530 }
 5531 #endif /* DDB */

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