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

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 2002-2006 Rice University
    5  * Copyright (c) 2007 Alan L. Cox <alc@cs.rice.edu>
    6  * All rights reserved.
    7  *
    8  * This software was developed for the FreeBSD Project by Alan L. Cox,
    9  * Olivier Crameri, Peter Druschel, Sitaram Iyer, and Juan Navarro.
   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  *
   20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   23  * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT
   24  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   27  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
   30  * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   31  * POSSIBILITY OF SUCH DAMAGE.
   32  */
   33 
   34 /*
   35  *      Physical memory system implementation
   36  *
   37  * Any external functions defined by this module are only to be used by the
   38  * virtual memory system.
   39  */
   40 
   41 #include <sys/cdefs.h>
   42 __FBSDID("$FreeBSD: releng/12.0/sys/vm/vm_phys.c 340007 2018-11-01 16:50:19Z markj $");
   43 
   44 #include "opt_ddb.h"
   45 #include "opt_vm.h"
   46 
   47 #include <sys/param.h>
   48 #include <sys/systm.h>
   49 #include <sys/domainset.h>
   50 #include <sys/lock.h>
   51 #include <sys/kernel.h>
   52 #include <sys/malloc.h>
   53 #include <sys/mutex.h>
   54 #include <sys/proc.h>
   55 #include <sys/queue.h>
   56 #include <sys/rwlock.h>
   57 #include <sys/sbuf.h>
   58 #include <sys/sysctl.h>
   59 #include <sys/tree.h>
   60 #include <sys/vmmeter.h>
   61 #include <sys/seq.h>
   62 
   63 #include <ddb/ddb.h>
   64 
   65 #include <vm/vm.h>
   66 #include <vm/vm_param.h>
   67 #include <vm/vm_kern.h>
   68 #include <vm/vm_object.h>
   69 #include <vm/vm_page.h>
   70 #include <vm/vm_phys.h>
   71 #include <vm/vm_pagequeue.h>
   72 
   73 _Static_assert(sizeof(long) * NBBY >= VM_PHYSSEG_MAX,
   74     "Too many physsegs.");
   75 
   76 #ifdef NUMA
   77 struct mem_affinity __read_mostly *mem_affinity;
   78 int __read_mostly *mem_locality;
   79 #endif
   80 
   81 int __read_mostly vm_ndomains = 1;
   82 domainset_t __read_mostly all_domains = DOMAINSET_T_INITIALIZER(0x1);
   83 
   84 struct vm_phys_seg __read_mostly vm_phys_segs[VM_PHYSSEG_MAX];
   85 int __read_mostly vm_phys_nsegs;
   86 
   87 struct vm_phys_fictitious_seg;
   88 static int vm_phys_fictitious_cmp(struct vm_phys_fictitious_seg *,
   89     struct vm_phys_fictitious_seg *);
   90 
   91 RB_HEAD(fict_tree, vm_phys_fictitious_seg) vm_phys_fictitious_tree =
   92     RB_INITIALIZER(_vm_phys_fictitious_tree);
   93 
   94 struct vm_phys_fictitious_seg {
   95         RB_ENTRY(vm_phys_fictitious_seg) node;
   96         /* Memory region data */
   97         vm_paddr_t      start;
   98         vm_paddr_t      end;
   99         vm_page_t       first_page;
  100 };
  101 
  102 RB_GENERATE_STATIC(fict_tree, vm_phys_fictitious_seg, node,
  103     vm_phys_fictitious_cmp);
  104 
  105 static struct rwlock_padalign vm_phys_fictitious_reg_lock;
  106 MALLOC_DEFINE(M_FICT_PAGES, "vm_fictitious", "Fictitious VM pages");
  107 
  108 static struct vm_freelist __aligned(CACHE_LINE_SIZE)
  109     vm_phys_free_queues[MAXMEMDOM][VM_NFREELIST][VM_NFREEPOOL][VM_NFREEORDER];
  110 
  111 static int __read_mostly vm_nfreelists;
  112 
  113 /*
  114  * Provides the mapping from VM_FREELIST_* to free list indices (flind).
  115  */
  116 static int __read_mostly vm_freelist_to_flind[VM_NFREELIST];
  117 
  118 CTASSERT(VM_FREELIST_DEFAULT == 0);
  119 
  120 #ifdef VM_FREELIST_DMA32
  121 #define VM_DMA32_BOUNDARY       ((vm_paddr_t)1 << 32)
  122 #endif
  123 
  124 /*
  125  * Enforce the assumptions made by vm_phys_add_seg() and vm_phys_init() about
  126  * the ordering of the free list boundaries.
  127  */
  128 #if defined(VM_LOWMEM_BOUNDARY) && defined(VM_DMA32_BOUNDARY)
  129 CTASSERT(VM_LOWMEM_BOUNDARY < VM_DMA32_BOUNDARY);
  130 #endif
  131 
  132 static int sysctl_vm_phys_free(SYSCTL_HANDLER_ARGS);
  133 SYSCTL_OID(_vm, OID_AUTO, phys_free, CTLTYPE_STRING | CTLFLAG_RD,
  134     NULL, 0, sysctl_vm_phys_free, "A", "Phys Free Info");
  135 
  136 static int sysctl_vm_phys_segs(SYSCTL_HANDLER_ARGS);
  137 SYSCTL_OID(_vm, OID_AUTO, phys_segs, CTLTYPE_STRING | CTLFLAG_RD,
  138     NULL, 0, sysctl_vm_phys_segs, "A", "Phys Seg Info");
  139 
  140 #ifdef NUMA
  141 static int sysctl_vm_phys_locality(SYSCTL_HANDLER_ARGS);
  142 SYSCTL_OID(_vm, OID_AUTO, phys_locality, CTLTYPE_STRING | CTLFLAG_RD,
  143     NULL, 0, sysctl_vm_phys_locality, "A", "Phys Locality Info");
  144 #endif
  145 
  146 SYSCTL_INT(_vm, OID_AUTO, ndomains, CTLFLAG_RD,
  147     &vm_ndomains, 0, "Number of physical memory domains available.");
  148 
  149 static vm_page_t vm_phys_alloc_seg_contig(struct vm_phys_seg *seg,
  150     u_long npages, vm_paddr_t low, vm_paddr_t high, u_long alignment,
  151     vm_paddr_t boundary);
  152 static void _vm_phys_create_seg(vm_paddr_t start, vm_paddr_t end, int domain);
  153 static void vm_phys_create_seg(vm_paddr_t start, vm_paddr_t end);
  154 static void vm_phys_split_pages(vm_page_t m, int oind, struct vm_freelist *fl,
  155     int order, int tail);
  156 
  157 /*
  158  * Red-black tree helpers for vm fictitious range management.
  159  */
  160 static inline int
  161 vm_phys_fictitious_in_range(struct vm_phys_fictitious_seg *p,
  162     struct vm_phys_fictitious_seg *range)
  163 {
  164 
  165         KASSERT(range->start != 0 && range->end != 0,
  166             ("Invalid range passed on search for vm_fictitious page"));
  167         if (p->start >= range->end)
  168                 return (1);
  169         if (p->start < range->start)
  170                 return (-1);
  171 
  172         return (0);
  173 }
  174 
  175 static int
  176 vm_phys_fictitious_cmp(struct vm_phys_fictitious_seg *p1,
  177     struct vm_phys_fictitious_seg *p2)
  178 {
  179 
  180         /* Check if this is a search for a page */
  181         if (p1->end == 0)
  182                 return (vm_phys_fictitious_in_range(p1, p2));
  183 
  184         KASSERT(p2->end != 0,
  185     ("Invalid range passed as second parameter to vm fictitious comparison"));
  186 
  187         /* Searching to add a new range */
  188         if (p1->end <= p2->start)
  189                 return (-1);
  190         if (p1->start >= p2->end)
  191                 return (1);
  192 
  193         panic("Trying to add overlapping vm fictitious ranges:\n"
  194             "[%#jx:%#jx] and [%#jx:%#jx]", (uintmax_t)p1->start,
  195             (uintmax_t)p1->end, (uintmax_t)p2->start, (uintmax_t)p2->end);
  196 }
  197 
  198 int
  199 vm_phys_domain_match(int prefer, vm_paddr_t low, vm_paddr_t high)
  200 {
  201 #ifdef NUMA
  202         domainset_t mask;
  203         int i;
  204 
  205         if (vm_ndomains == 1 || mem_affinity == NULL)
  206                 return (0);
  207 
  208         DOMAINSET_ZERO(&mask);
  209         /*
  210          * Check for any memory that overlaps low, high.
  211          */
  212         for (i = 0; mem_affinity[i].end != 0; i++)
  213                 if (mem_affinity[i].start <= high &&
  214                     mem_affinity[i].end >= low)
  215                         DOMAINSET_SET(mem_affinity[i].domain, &mask);
  216         if (prefer != -1 && DOMAINSET_ISSET(prefer, &mask))
  217                 return (prefer);
  218         if (DOMAINSET_EMPTY(&mask))
  219                 panic("vm_phys_domain_match:  Impossible constraint");
  220         return (DOMAINSET_FFS(&mask) - 1);
  221 #else
  222         return (0);
  223 #endif
  224 }
  225 
  226 /*
  227  * Outputs the state of the physical memory allocator, specifically,
  228  * the amount of physical memory in each free list.
  229  */
  230 static int
  231 sysctl_vm_phys_free(SYSCTL_HANDLER_ARGS)
  232 {
  233         struct sbuf sbuf;
  234         struct vm_freelist *fl;
  235         int dom, error, flind, oind, pind;
  236 
  237         error = sysctl_wire_old_buffer(req, 0);
  238         if (error != 0)
  239                 return (error);
  240         sbuf_new_for_sysctl(&sbuf, NULL, 128 * vm_ndomains, req);
  241         for (dom = 0; dom < vm_ndomains; dom++) {
  242                 sbuf_printf(&sbuf,"\nDOMAIN %d:\n", dom);
  243                 for (flind = 0; flind < vm_nfreelists; flind++) {
  244                         sbuf_printf(&sbuf, "\nFREE LIST %d:\n"
  245                             "\n  ORDER (SIZE)  |  NUMBER"
  246                             "\n              ", flind);
  247                         for (pind = 0; pind < VM_NFREEPOOL; pind++)
  248                                 sbuf_printf(&sbuf, "  |  POOL %d", pind);
  249                         sbuf_printf(&sbuf, "\n--            ");
  250                         for (pind = 0; pind < VM_NFREEPOOL; pind++)
  251                                 sbuf_printf(&sbuf, "-- --      ");
  252                         sbuf_printf(&sbuf, "--\n");
  253                         for (oind = VM_NFREEORDER - 1; oind >= 0; oind--) {
  254                                 sbuf_printf(&sbuf, "  %2d (%6dK)", oind,
  255                                     1 << (PAGE_SHIFT - 10 + oind));
  256                                 for (pind = 0; pind < VM_NFREEPOOL; pind++) {
  257                                 fl = vm_phys_free_queues[dom][flind][pind];
  258                                         sbuf_printf(&sbuf, "  |  %6d",
  259                                             fl[oind].lcnt);
  260                                 }
  261                                 sbuf_printf(&sbuf, "\n");
  262                         }
  263                 }
  264         }
  265         error = sbuf_finish(&sbuf);
  266         sbuf_delete(&sbuf);
  267         return (error);
  268 }
  269 
  270 /*
  271  * Outputs the set of physical memory segments.
  272  */
  273 static int
  274 sysctl_vm_phys_segs(SYSCTL_HANDLER_ARGS)
  275 {
  276         struct sbuf sbuf;
  277         struct vm_phys_seg *seg;
  278         int error, segind;
  279 
  280         error = sysctl_wire_old_buffer(req, 0);
  281         if (error != 0)
  282                 return (error);
  283         sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
  284         for (segind = 0; segind < vm_phys_nsegs; segind++) {
  285                 sbuf_printf(&sbuf, "\nSEGMENT %d:\n\n", segind);
  286                 seg = &vm_phys_segs[segind];
  287                 sbuf_printf(&sbuf, "start:     %#jx\n",
  288                     (uintmax_t)seg->start);
  289                 sbuf_printf(&sbuf, "end:       %#jx\n",
  290                     (uintmax_t)seg->end);
  291                 sbuf_printf(&sbuf, "domain:    %d\n", seg->domain);
  292                 sbuf_printf(&sbuf, "free list: %p\n", seg->free_queues);
  293         }
  294         error = sbuf_finish(&sbuf);
  295         sbuf_delete(&sbuf);
  296         return (error);
  297 }
  298 
  299 /*
  300  * Return affinity, or -1 if there's no affinity information.
  301  */
  302 int
  303 vm_phys_mem_affinity(int f, int t)
  304 {
  305 
  306 #ifdef NUMA
  307         if (mem_locality == NULL)
  308                 return (-1);
  309         if (f >= vm_ndomains || t >= vm_ndomains)
  310                 return (-1);
  311         return (mem_locality[f * vm_ndomains + t]);
  312 #else
  313         return (-1);
  314 #endif
  315 }
  316 
  317 #ifdef NUMA
  318 /*
  319  * Outputs the VM locality table.
  320  */
  321 static int
  322 sysctl_vm_phys_locality(SYSCTL_HANDLER_ARGS)
  323 {
  324         struct sbuf sbuf;
  325         int error, i, j;
  326 
  327         error = sysctl_wire_old_buffer(req, 0);
  328         if (error != 0)
  329                 return (error);
  330         sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
  331 
  332         sbuf_printf(&sbuf, "\n");
  333 
  334         for (i = 0; i < vm_ndomains; i++) {
  335                 sbuf_printf(&sbuf, "%d: ", i);
  336                 for (j = 0; j < vm_ndomains; j++) {
  337                         sbuf_printf(&sbuf, "%d ", vm_phys_mem_affinity(i, j));
  338                 }
  339                 sbuf_printf(&sbuf, "\n");
  340         }
  341         error = sbuf_finish(&sbuf);
  342         sbuf_delete(&sbuf);
  343         return (error);
  344 }
  345 #endif
  346 
  347 static void
  348 vm_freelist_add(struct vm_freelist *fl, vm_page_t m, int order, int tail)
  349 {
  350 
  351         m->order = order;
  352         if (tail)
  353                 TAILQ_INSERT_TAIL(&fl[order].pl, m, listq);
  354         else
  355                 TAILQ_INSERT_HEAD(&fl[order].pl, m, listq);
  356         fl[order].lcnt++;
  357 }
  358 
  359 static void
  360 vm_freelist_rem(struct vm_freelist *fl, vm_page_t m, int order)
  361 {
  362 
  363         TAILQ_REMOVE(&fl[order].pl, m, listq);
  364         fl[order].lcnt--;
  365         m->order = VM_NFREEORDER;
  366 }
  367 
  368 /*
  369  * Create a physical memory segment.
  370  */
  371 static void
  372 _vm_phys_create_seg(vm_paddr_t start, vm_paddr_t end, int domain)
  373 {
  374         struct vm_phys_seg *seg;
  375 
  376         KASSERT(vm_phys_nsegs < VM_PHYSSEG_MAX,
  377             ("vm_phys_create_seg: increase VM_PHYSSEG_MAX"));
  378         KASSERT(domain >= 0 && domain < vm_ndomains,
  379             ("vm_phys_create_seg: invalid domain provided"));
  380         seg = &vm_phys_segs[vm_phys_nsegs++];
  381         while (seg > vm_phys_segs && (seg - 1)->start >= end) {
  382                 *seg = *(seg - 1);
  383                 seg--;
  384         }
  385         seg->start = start;
  386         seg->end = end;
  387         seg->domain = domain;
  388 }
  389 
  390 static void
  391 vm_phys_create_seg(vm_paddr_t start, vm_paddr_t end)
  392 {
  393 #ifdef NUMA
  394         int i;
  395 
  396         if (mem_affinity == NULL) {
  397                 _vm_phys_create_seg(start, end, 0);
  398                 return;
  399         }
  400 
  401         for (i = 0;; i++) {
  402                 if (mem_affinity[i].end == 0)
  403                         panic("Reached end of affinity info");
  404                 if (mem_affinity[i].end <= start)
  405                         continue;
  406                 if (mem_affinity[i].start > start)
  407                         panic("No affinity info for start %jx",
  408                             (uintmax_t)start);
  409                 if (mem_affinity[i].end >= end) {
  410                         _vm_phys_create_seg(start, end,
  411                             mem_affinity[i].domain);
  412                         break;
  413                 }
  414                 _vm_phys_create_seg(start, mem_affinity[i].end,
  415                     mem_affinity[i].domain);
  416                 start = mem_affinity[i].end;
  417         }
  418 #else
  419         _vm_phys_create_seg(start, end, 0);
  420 #endif
  421 }
  422 
  423 /*
  424  * Add a physical memory segment.
  425  */
  426 void
  427 vm_phys_add_seg(vm_paddr_t start, vm_paddr_t end)
  428 {
  429         vm_paddr_t paddr;
  430 
  431         KASSERT((start & PAGE_MASK) == 0,
  432             ("vm_phys_define_seg: start is not page aligned"));
  433         KASSERT((end & PAGE_MASK) == 0,
  434             ("vm_phys_define_seg: end is not page aligned"));
  435 
  436         /*
  437          * Split the physical memory segment if it spans two or more free
  438          * list boundaries.
  439          */
  440         paddr = start;
  441 #ifdef  VM_FREELIST_LOWMEM
  442         if (paddr < VM_LOWMEM_BOUNDARY && end > VM_LOWMEM_BOUNDARY) {
  443                 vm_phys_create_seg(paddr, VM_LOWMEM_BOUNDARY);
  444                 paddr = VM_LOWMEM_BOUNDARY;
  445         }
  446 #endif
  447 #ifdef  VM_FREELIST_DMA32
  448         if (paddr < VM_DMA32_BOUNDARY && end > VM_DMA32_BOUNDARY) {
  449                 vm_phys_create_seg(paddr, VM_DMA32_BOUNDARY);
  450                 paddr = VM_DMA32_BOUNDARY;
  451         }
  452 #endif
  453         vm_phys_create_seg(paddr, end);
  454 }
  455 
  456 /*
  457  * Initialize the physical memory allocator.
  458  *
  459  * Requires that vm_page_array is initialized!
  460  */
  461 void
  462 vm_phys_init(void)
  463 {
  464         struct vm_freelist *fl;
  465         struct vm_phys_seg *end_seg, *prev_seg, *seg, *tmp_seg;
  466         u_long npages;
  467         int dom, flind, freelist, oind, pind, segind;
  468 
  469         /*
  470          * Compute the number of free lists, and generate the mapping from the
  471          * manifest constants VM_FREELIST_* to the free list indices.
  472          *
  473          * Initially, the entries of vm_freelist_to_flind[] are set to either
  474          * 0 or 1 to indicate which free lists should be created.
  475          */
  476         npages = 0;
  477         for (segind = vm_phys_nsegs - 1; segind >= 0; segind--) {
  478                 seg = &vm_phys_segs[segind];
  479 #ifdef  VM_FREELIST_LOWMEM
  480                 if (seg->end <= VM_LOWMEM_BOUNDARY)
  481                         vm_freelist_to_flind[VM_FREELIST_LOWMEM] = 1;
  482                 else
  483 #endif
  484 #ifdef  VM_FREELIST_DMA32
  485                 if (
  486 #ifdef  VM_DMA32_NPAGES_THRESHOLD
  487                     /*
  488                      * Create the DMA32 free list only if the amount of
  489                      * physical memory above physical address 4G exceeds the
  490                      * given threshold.
  491                      */
  492                     npages > VM_DMA32_NPAGES_THRESHOLD &&
  493 #endif
  494                     seg->end <= VM_DMA32_BOUNDARY)
  495                         vm_freelist_to_flind[VM_FREELIST_DMA32] = 1;
  496                 else
  497 #endif
  498                 {
  499                         npages += atop(seg->end - seg->start);
  500                         vm_freelist_to_flind[VM_FREELIST_DEFAULT] = 1;
  501                 }
  502         }
  503         /* Change each entry into a running total of the free lists. */
  504         for (freelist = 1; freelist < VM_NFREELIST; freelist++) {
  505                 vm_freelist_to_flind[freelist] +=
  506                     vm_freelist_to_flind[freelist - 1];
  507         }
  508         vm_nfreelists = vm_freelist_to_flind[VM_NFREELIST - 1];
  509         KASSERT(vm_nfreelists > 0, ("vm_phys_init: no free lists"));
  510         /* Change each entry into a free list index. */
  511         for (freelist = 0; freelist < VM_NFREELIST; freelist++)
  512                 vm_freelist_to_flind[freelist]--;
  513 
  514         /*
  515          * Initialize the first_page and free_queues fields of each physical
  516          * memory segment.
  517          */
  518 #ifdef VM_PHYSSEG_SPARSE
  519         npages = 0;
  520 #endif
  521         for (segind = 0; segind < vm_phys_nsegs; segind++) {
  522                 seg = &vm_phys_segs[segind];
  523 #ifdef VM_PHYSSEG_SPARSE
  524                 seg->first_page = &vm_page_array[npages];
  525                 npages += atop(seg->end - seg->start);
  526 #else
  527                 seg->first_page = PHYS_TO_VM_PAGE(seg->start);
  528 #endif
  529 #ifdef  VM_FREELIST_LOWMEM
  530                 if (seg->end <= VM_LOWMEM_BOUNDARY) {
  531                         flind = vm_freelist_to_flind[VM_FREELIST_LOWMEM];
  532                         KASSERT(flind >= 0,
  533                             ("vm_phys_init: LOWMEM flind < 0"));
  534                 } else
  535 #endif
  536 #ifdef  VM_FREELIST_DMA32
  537                 if (seg->end <= VM_DMA32_BOUNDARY) {
  538                         flind = vm_freelist_to_flind[VM_FREELIST_DMA32];
  539                         KASSERT(flind >= 0,
  540                             ("vm_phys_init: DMA32 flind < 0"));
  541                 } else
  542 #endif
  543                 {
  544                         flind = vm_freelist_to_flind[VM_FREELIST_DEFAULT];
  545                         KASSERT(flind >= 0,
  546                             ("vm_phys_init: DEFAULT flind < 0"));
  547                 }
  548                 seg->free_queues = &vm_phys_free_queues[seg->domain][flind];
  549         }
  550 
  551         /*
  552          * Coalesce physical memory segments that are contiguous and share the
  553          * same per-domain free queues.
  554          */
  555         prev_seg = vm_phys_segs;
  556         seg = &vm_phys_segs[1];
  557         end_seg = &vm_phys_segs[vm_phys_nsegs];
  558         while (seg < end_seg) {
  559                 if (prev_seg->end == seg->start &&
  560                     prev_seg->free_queues == seg->free_queues) {
  561                         prev_seg->end = seg->end;
  562                         KASSERT(prev_seg->domain == seg->domain,
  563                             ("vm_phys_init: free queues cannot span domains"));
  564                         vm_phys_nsegs--;
  565                         end_seg--;
  566                         for (tmp_seg = seg; tmp_seg < end_seg; tmp_seg++)
  567                                 *tmp_seg = *(tmp_seg + 1);
  568                 } else {
  569                         prev_seg = seg;
  570                         seg++;
  571                 }
  572         }
  573 
  574         /*
  575          * Initialize the free queues.
  576          */
  577         for (dom = 0; dom < vm_ndomains; dom++) {
  578                 for (flind = 0; flind < vm_nfreelists; flind++) {
  579                         for (pind = 0; pind < VM_NFREEPOOL; pind++) {
  580                                 fl = vm_phys_free_queues[dom][flind][pind];
  581                                 for (oind = 0; oind < VM_NFREEORDER; oind++)
  582                                         TAILQ_INIT(&fl[oind].pl);
  583                         }
  584                 }
  585         }
  586 
  587         rw_init(&vm_phys_fictitious_reg_lock, "vmfctr");
  588 }
  589 
  590 /*
  591  * Register info about the NUMA topology of the system.
  592  *
  593  * Invoked by platform-dependent code prior to vm_phys_init().
  594  */
  595 void
  596 vm_phys_register_domains(int ndomains, struct mem_affinity *affinity,
  597     int *locality)
  598 {
  599 #ifdef NUMA
  600         int d, i;
  601 
  602         /*
  603          * For now the only override value that we support is 1, which
  604          * effectively disables NUMA-awareness in the allocators.
  605          */
  606         d = 0;
  607         TUNABLE_INT_FETCH("vm.numa.disabled", &d);
  608         if (d)
  609                 ndomains = 1;
  610 
  611         if (ndomains > 1) {
  612                 vm_ndomains = ndomains;
  613                 mem_affinity = affinity;
  614                 mem_locality = locality;
  615         }
  616 
  617         for (i = 0; i < vm_ndomains; i++)
  618                 DOMAINSET_SET(i, &all_domains);
  619 #else
  620         (void)ndomains;
  621         (void)affinity;
  622         (void)locality;
  623 #endif
  624 }
  625 
  626 /*
  627  * Split a contiguous, power of two-sized set of physical pages.
  628  *
  629  * When this function is called by a page allocation function, the caller
  630  * should request insertion at the head unless the order [order, oind) queues
  631  * are known to be empty.  The objective being to reduce the likelihood of
  632  * long-term fragmentation by promoting contemporaneous allocation and
  633  * (hopefully) deallocation.
  634  */
  635 static __inline void
  636 vm_phys_split_pages(vm_page_t m, int oind, struct vm_freelist *fl, int order,
  637     int tail)
  638 {
  639         vm_page_t m_buddy;
  640 
  641         while (oind > order) {
  642                 oind--;
  643                 m_buddy = &m[1 << oind];
  644                 KASSERT(m_buddy->order == VM_NFREEORDER,
  645                     ("vm_phys_split_pages: page %p has unexpected order %d",
  646                     m_buddy, m_buddy->order));
  647                 vm_freelist_add(fl, m_buddy, oind, tail);
  648         }
  649 }
  650 
  651 /*
  652  * Add the physical pages [m, m + npages) at the end of a power-of-two aligned
  653  * and sized set to the specified free list.
  654  *
  655  * When this function is called by a page allocation function, the caller
  656  * should request insertion at the head unless the lower-order queues are
  657  * known to be empty.  The objective being to reduce the likelihood of long-
  658  * term fragmentation by promoting contemporaneous allocation and (hopefully)
  659  * deallocation.
  660  *
  661  * The physical page m's buddy must not be free.
  662  */
  663 static void
  664 vm_phys_enq_range(vm_page_t m, u_int npages, struct vm_freelist *fl, int tail)
  665 {
  666         u_int n;
  667         int order;
  668 
  669         KASSERT(npages > 0, ("vm_phys_enq_range: npages is 0"));
  670         KASSERT(((VM_PAGE_TO_PHYS(m) + npages * PAGE_SIZE) &
  671             ((PAGE_SIZE << (fls(npages) - 1)) - 1)) == 0,
  672             ("vm_phys_enq_range: page %p and npages %u are misaligned",
  673             m, npages));
  674         do {
  675                 KASSERT(m->order == VM_NFREEORDER,
  676                     ("vm_phys_enq_range: page %p has unexpected order %d",
  677                     m, m->order));
  678                 order = ffs(npages) - 1;
  679                 KASSERT(order < VM_NFREEORDER,
  680                     ("vm_phys_enq_range: order %d is out of range", order));
  681                 vm_freelist_add(fl, m, order, tail);
  682                 n = 1 << order;
  683                 m += n;
  684                 npages -= n;
  685         } while (npages > 0);
  686 }
  687 
  688 /*
  689  * Tries to allocate the specified number of pages from the specified pool
  690  * within the specified domain.  Returns the actual number of allocated pages
  691  * and a pointer to each page through the array ma[].
  692  *
  693  * The returned pages may not be physically contiguous.  However, in contrast
  694  * to performing multiple, back-to-back calls to vm_phys_alloc_pages(..., 0),
  695  * calling this function once to allocate the desired number of pages will
  696  * avoid wasted time in vm_phys_split_pages().
  697  *
  698  * The free page queues for the specified domain must be locked.
  699  */
  700 int
  701 vm_phys_alloc_npages(int domain, int pool, int npages, vm_page_t ma[])
  702 {
  703         struct vm_freelist *alt, *fl;
  704         vm_page_t m;
  705         int avail, end, flind, freelist, i, need, oind, pind;
  706 
  707         KASSERT(domain >= 0 && domain < vm_ndomains,
  708             ("vm_phys_alloc_npages: domain %d is out of range", domain));
  709         KASSERT(pool < VM_NFREEPOOL,
  710             ("vm_phys_alloc_npages: pool %d is out of range", pool));
  711         KASSERT(npages <= 1 << (VM_NFREEORDER - 1),
  712             ("vm_phys_alloc_npages: npages %d is out of range", npages));
  713         vm_domain_free_assert_locked(VM_DOMAIN(domain));
  714         i = 0;
  715         for (freelist = 0; freelist < VM_NFREELIST; freelist++) {
  716                 flind = vm_freelist_to_flind[freelist];
  717                 if (flind < 0)
  718                         continue;
  719                 fl = vm_phys_free_queues[domain][flind][pool];
  720                 for (oind = 0; oind < VM_NFREEORDER; oind++) {
  721                         while ((m = TAILQ_FIRST(&fl[oind].pl)) != NULL) {
  722                                 vm_freelist_rem(fl, m, oind);
  723                                 avail = 1 << oind;
  724                                 need = imin(npages - i, avail);
  725                                 for (end = i + need; i < end;)
  726                                         ma[i++] = m++;
  727                                 if (need < avail) {
  728                                         /*
  729                                          * Return excess pages to fl.  Its
  730                                          * order [0, oind) queues are empty.
  731                                          */
  732                                         vm_phys_enq_range(m, avail - need, fl,
  733                                             1);
  734                                         return (npages);
  735                                 } else if (i == npages)
  736                                         return (npages);
  737                         }
  738                 }
  739                 for (oind = VM_NFREEORDER - 1; oind >= 0; oind--) {
  740                         for (pind = 0; pind < VM_NFREEPOOL; pind++) {
  741                                 alt = vm_phys_free_queues[domain][flind][pind];
  742                                 while ((m = TAILQ_FIRST(&alt[oind].pl)) !=
  743                                     NULL) {
  744                                         vm_freelist_rem(alt, m, oind);
  745                                         vm_phys_set_pool(pool, m, oind);
  746                                         avail = 1 << oind;
  747                                         need = imin(npages - i, avail);
  748                                         for (end = i + need; i < end;)
  749                                                 ma[i++] = m++;
  750                                         if (need < avail) {
  751                                                 /*
  752                                                  * Return excess pages to fl.
  753                                                  * Its order [0, oind) queues
  754                                                  * are empty.
  755                                                  */
  756                                                 vm_phys_enq_range(m, avail -
  757                                                     need, fl, 1);
  758                                                 return (npages);
  759                                         } else if (i == npages)
  760                                                 return (npages);
  761                                 }
  762                         }
  763                 }
  764         }
  765         return (i);
  766 }
  767 
  768 /*
  769  * Allocate a contiguous, power of two-sized set of physical pages
  770  * from the free lists.
  771  *
  772  * The free page queues must be locked.
  773  */
  774 vm_page_t
  775 vm_phys_alloc_pages(int domain, int pool, int order)
  776 {
  777         vm_page_t m;
  778         int freelist;
  779 
  780         for (freelist = 0; freelist < VM_NFREELIST; freelist++) {
  781                 m = vm_phys_alloc_freelist_pages(domain, freelist, pool, order);
  782                 if (m != NULL)
  783                         return (m);
  784         }
  785         return (NULL);
  786 }
  787 
  788 /*
  789  * Allocate a contiguous, power of two-sized set of physical pages from the
  790  * specified free list.  The free list must be specified using one of the
  791  * manifest constants VM_FREELIST_*.
  792  *
  793  * The free page queues must be locked.
  794  */
  795 vm_page_t
  796 vm_phys_alloc_freelist_pages(int domain, int freelist, int pool, int order)
  797 {
  798         struct vm_freelist *alt, *fl;
  799         vm_page_t m;
  800         int oind, pind, flind;
  801 
  802         KASSERT(domain >= 0 && domain < vm_ndomains,
  803             ("vm_phys_alloc_freelist_pages: domain %d is out of range",
  804             domain));
  805         KASSERT(freelist < VM_NFREELIST,
  806             ("vm_phys_alloc_freelist_pages: freelist %d is out of range",
  807             freelist));
  808         KASSERT(pool < VM_NFREEPOOL,
  809             ("vm_phys_alloc_freelist_pages: pool %d is out of range", pool));
  810         KASSERT(order < VM_NFREEORDER,
  811             ("vm_phys_alloc_freelist_pages: order %d is out of range", order));
  812 
  813         flind = vm_freelist_to_flind[freelist];
  814         /* Check if freelist is present */
  815         if (flind < 0)
  816                 return (NULL);
  817 
  818         vm_domain_free_assert_locked(VM_DOMAIN(domain));
  819         fl = &vm_phys_free_queues[domain][flind][pool][0];
  820         for (oind = order; oind < VM_NFREEORDER; oind++) {
  821                 m = TAILQ_FIRST(&fl[oind].pl);
  822                 if (m != NULL) {
  823                         vm_freelist_rem(fl, m, oind);
  824                         /* The order [order, oind) queues are empty. */
  825                         vm_phys_split_pages(m, oind, fl, order, 1);
  826                         return (m);
  827                 }
  828         }
  829 
  830         /*
  831          * The given pool was empty.  Find the largest
  832          * contiguous, power-of-two-sized set of pages in any
  833          * pool.  Transfer these pages to the given pool, and
  834          * use them to satisfy the allocation.
  835          */
  836         for (oind = VM_NFREEORDER - 1; oind >= order; oind--) {
  837                 for (pind = 0; pind < VM_NFREEPOOL; pind++) {
  838                         alt = &vm_phys_free_queues[domain][flind][pind][0];
  839                         m = TAILQ_FIRST(&alt[oind].pl);
  840                         if (m != NULL) {
  841                                 vm_freelist_rem(alt, m, oind);
  842                                 vm_phys_set_pool(pool, m, oind);
  843                                 /* The order [order, oind) queues are empty. */
  844                                 vm_phys_split_pages(m, oind, fl, order, 1);
  845                                 return (m);
  846                         }
  847                 }
  848         }
  849         return (NULL);
  850 }
  851 
  852 /*
  853  * Find the vm_page corresponding to the given physical address.
  854  */
  855 vm_page_t
  856 vm_phys_paddr_to_vm_page(vm_paddr_t pa)
  857 {
  858         struct vm_phys_seg *seg;
  859         int segind;
  860 
  861         for (segind = 0; segind < vm_phys_nsegs; segind++) {
  862                 seg = &vm_phys_segs[segind];
  863                 if (pa >= seg->start && pa < seg->end)
  864                         return (&seg->first_page[atop(pa - seg->start)]);
  865         }
  866         return (NULL);
  867 }
  868 
  869 vm_page_t
  870 vm_phys_fictitious_to_vm_page(vm_paddr_t pa)
  871 {
  872         struct vm_phys_fictitious_seg tmp, *seg;
  873         vm_page_t m;
  874 
  875         m = NULL;
  876         tmp.start = pa;
  877         tmp.end = 0;
  878 
  879         rw_rlock(&vm_phys_fictitious_reg_lock);
  880         seg = RB_FIND(fict_tree, &vm_phys_fictitious_tree, &tmp);
  881         rw_runlock(&vm_phys_fictitious_reg_lock);
  882         if (seg == NULL)
  883                 return (NULL);
  884 
  885         m = &seg->first_page[atop(pa - seg->start)];
  886         KASSERT((m->flags & PG_FICTITIOUS) != 0, ("%p not fictitious", m));
  887 
  888         return (m);
  889 }
  890 
  891 static inline void
  892 vm_phys_fictitious_init_range(vm_page_t range, vm_paddr_t start,
  893     long page_count, vm_memattr_t memattr)
  894 {
  895         long i;
  896 
  897         bzero(range, page_count * sizeof(*range));
  898         for (i = 0; i < page_count; i++) {
  899                 vm_page_initfake(&range[i], start + PAGE_SIZE * i, memattr);
  900                 range[i].oflags &= ~VPO_UNMANAGED;
  901                 range[i].busy_lock = VPB_UNBUSIED;
  902         }
  903 }
  904 
  905 int
  906 vm_phys_fictitious_reg_range(vm_paddr_t start, vm_paddr_t end,
  907     vm_memattr_t memattr)
  908 {
  909         struct vm_phys_fictitious_seg *seg;
  910         vm_page_t fp;
  911         long page_count;
  912 #ifdef VM_PHYSSEG_DENSE
  913         long pi, pe;
  914         long dpage_count;
  915 #endif
  916 
  917         KASSERT(start < end,
  918             ("Start of segment isn't less than end (start: %jx end: %jx)",
  919             (uintmax_t)start, (uintmax_t)end));
  920 
  921         page_count = (end - start) / PAGE_SIZE;
  922 
  923 #ifdef VM_PHYSSEG_DENSE
  924         pi = atop(start);
  925         pe = atop(end);
  926         if (pi >= first_page && (pi - first_page) < vm_page_array_size) {
  927                 fp = &vm_page_array[pi - first_page];
  928                 if ((pe - first_page) > vm_page_array_size) {
  929                         /*
  930                          * We have a segment that starts inside
  931                          * of vm_page_array, but ends outside of it.
  932                          *
  933                          * Use vm_page_array pages for those that are
  934                          * inside of the vm_page_array range, and
  935                          * allocate the remaining ones.
  936                          */
  937                         dpage_count = vm_page_array_size - (pi - first_page);
  938                         vm_phys_fictitious_init_range(fp, start, dpage_count,
  939                             memattr);
  940                         page_count -= dpage_count;
  941                         start += ptoa(dpage_count);
  942                         goto alloc;
  943                 }
  944                 /*
  945                  * We can allocate the full range from vm_page_array,
  946                  * so there's no need to register the range in the tree.
  947                  */
  948                 vm_phys_fictitious_init_range(fp, start, page_count, memattr);
  949                 return (0);
  950         } else if (pe > first_page && (pe - first_page) < vm_page_array_size) {
  951                 /*
  952                  * We have a segment that ends inside of vm_page_array,
  953                  * but starts outside of it.
  954                  */
  955                 fp = &vm_page_array[0];
  956                 dpage_count = pe - first_page;
  957                 vm_phys_fictitious_init_range(fp, ptoa(first_page), dpage_count,
  958                     memattr);
  959                 end -= ptoa(dpage_count);
  960                 page_count -= dpage_count;
  961                 goto alloc;
  962         } else if (pi < first_page && pe > (first_page + vm_page_array_size)) {
  963                 /*
  964                  * Trying to register a fictitious range that expands before
  965                  * and after vm_page_array.
  966                  */
  967                 return (EINVAL);
  968         } else {
  969 alloc:
  970 #endif
  971                 fp = malloc(page_count * sizeof(struct vm_page), M_FICT_PAGES,
  972                     M_WAITOK);
  973 #ifdef VM_PHYSSEG_DENSE
  974         }
  975 #endif
  976         vm_phys_fictitious_init_range(fp, start, page_count, memattr);
  977 
  978         seg = malloc(sizeof(*seg), M_FICT_PAGES, M_WAITOK | M_ZERO);
  979         seg->start = start;
  980         seg->end = end;
  981         seg->first_page = fp;
  982 
  983         rw_wlock(&vm_phys_fictitious_reg_lock);
  984         RB_INSERT(fict_tree, &vm_phys_fictitious_tree, seg);
  985         rw_wunlock(&vm_phys_fictitious_reg_lock);
  986 
  987         return (0);
  988 }
  989 
  990 void
  991 vm_phys_fictitious_unreg_range(vm_paddr_t start, vm_paddr_t end)
  992 {
  993         struct vm_phys_fictitious_seg *seg, tmp;
  994 #ifdef VM_PHYSSEG_DENSE
  995         long pi, pe;
  996 #endif
  997 
  998         KASSERT(start < end,
  999             ("Start of segment isn't less than end (start: %jx end: %jx)",
 1000             (uintmax_t)start, (uintmax_t)end));
 1001 
 1002 #ifdef VM_PHYSSEG_DENSE
 1003         pi = atop(start);
 1004         pe = atop(end);
 1005         if (pi >= first_page && (pi - first_page) < vm_page_array_size) {
 1006                 if ((pe - first_page) <= vm_page_array_size) {
 1007                         /*
 1008                          * This segment was allocated using vm_page_array
 1009                          * only, there's nothing to do since those pages
 1010                          * were never added to the tree.
 1011                          */
 1012                         return;
 1013                 }
 1014                 /*
 1015                  * We have a segment that starts inside
 1016                  * of vm_page_array, but ends outside of it.
 1017                  *
 1018                  * Calculate how many pages were added to the
 1019                  * tree and free them.
 1020                  */
 1021                 start = ptoa(first_page + vm_page_array_size);
 1022         } else if (pe > first_page && (pe - first_page) < vm_page_array_size) {
 1023                 /*
 1024                  * We have a segment that ends inside of vm_page_array,
 1025                  * but starts outside of it.
 1026                  */
 1027                 end = ptoa(first_page);
 1028         } else if (pi < first_page && pe > (first_page + vm_page_array_size)) {
 1029                 /* Since it's not possible to register such a range, panic. */
 1030                 panic(
 1031                     "Unregistering not registered fictitious range [%#jx:%#jx]",
 1032                     (uintmax_t)start, (uintmax_t)end);
 1033         }
 1034 #endif
 1035         tmp.start = start;
 1036         tmp.end = 0;
 1037 
 1038         rw_wlock(&vm_phys_fictitious_reg_lock);
 1039         seg = RB_FIND(fict_tree, &vm_phys_fictitious_tree, &tmp);
 1040         if (seg->start != start || seg->end != end) {
 1041                 rw_wunlock(&vm_phys_fictitious_reg_lock);
 1042                 panic(
 1043                     "Unregistering not registered fictitious range [%#jx:%#jx]",
 1044                     (uintmax_t)start, (uintmax_t)end);
 1045         }
 1046         RB_REMOVE(fict_tree, &vm_phys_fictitious_tree, seg);
 1047         rw_wunlock(&vm_phys_fictitious_reg_lock);
 1048         free(seg->first_page, M_FICT_PAGES);
 1049         free(seg, M_FICT_PAGES);
 1050 }
 1051 
 1052 /*
 1053  * Free a contiguous, power of two-sized set of physical pages.
 1054  *
 1055  * The free page queues must be locked.
 1056  */
 1057 void
 1058 vm_phys_free_pages(vm_page_t m, int order)
 1059 {
 1060         struct vm_freelist *fl;
 1061         struct vm_phys_seg *seg;
 1062         vm_paddr_t pa;
 1063         vm_page_t m_buddy;
 1064 
 1065         KASSERT(m->order == VM_NFREEORDER,
 1066             ("vm_phys_free_pages: page %p has unexpected order %d",
 1067             m, m->order));
 1068         KASSERT(m->pool < VM_NFREEPOOL,
 1069             ("vm_phys_free_pages: page %p has unexpected pool %d",
 1070             m, m->pool));
 1071         KASSERT(order < VM_NFREEORDER,
 1072             ("vm_phys_free_pages: order %d is out of range", order));
 1073         seg = &vm_phys_segs[m->segind];
 1074         vm_domain_free_assert_locked(VM_DOMAIN(seg->domain));
 1075         if (order < VM_NFREEORDER - 1) {
 1076                 pa = VM_PAGE_TO_PHYS(m);
 1077                 do {
 1078                         pa ^= ((vm_paddr_t)1 << (PAGE_SHIFT + order));
 1079                         if (pa < seg->start || pa >= seg->end)
 1080                                 break;
 1081                         m_buddy = &seg->first_page[atop(pa - seg->start)];
 1082                         if (m_buddy->order != order)
 1083                                 break;
 1084                         fl = (*seg->free_queues)[m_buddy->pool];
 1085                         vm_freelist_rem(fl, m_buddy, order);
 1086                         if (m_buddy->pool != m->pool)
 1087                                 vm_phys_set_pool(m->pool, m_buddy, order);
 1088                         order++;
 1089                         pa &= ~(((vm_paddr_t)1 << (PAGE_SHIFT + order)) - 1);
 1090                         m = &seg->first_page[atop(pa - seg->start)];
 1091                 } while (order < VM_NFREEORDER - 1);
 1092         }
 1093         fl = (*seg->free_queues)[m->pool];
 1094         vm_freelist_add(fl, m, order, 1);
 1095 }
 1096 
 1097 /*
 1098  * Free a contiguous, arbitrarily sized set of physical pages.
 1099  *
 1100  * The free page queues must be locked.
 1101  */
 1102 void
 1103 vm_phys_free_contig(vm_page_t m, u_long npages)
 1104 {
 1105         u_int n;
 1106         int order;
 1107 
 1108         /*
 1109          * Avoid unnecessary coalescing by freeing the pages in the largest
 1110          * possible power-of-two-sized subsets.
 1111          */
 1112         vm_domain_free_assert_locked(vm_pagequeue_domain(m));
 1113         for (;; npages -= n) {
 1114                 /*
 1115                  * Unsigned "min" is used here so that "order" is assigned
 1116                  * "VM_NFREEORDER - 1" when "m"'s physical address is zero
 1117                  * or the low-order bits of its physical address are zero
 1118                  * because the size of a physical address exceeds the size of
 1119                  * a long.
 1120                  */
 1121                 order = min(ffsl(VM_PAGE_TO_PHYS(m) >> PAGE_SHIFT) - 1,
 1122                     VM_NFREEORDER - 1);
 1123                 n = 1 << order;
 1124                 if (npages < n)
 1125                         break;
 1126                 vm_phys_free_pages(m, order);
 1127                 m += n;
 1128         }
 1129         /* The residual "npages" is less than "1 << (VM_NFREEORDER - 1)". */
 1130         for (; npages > 0; npages -= n) {
 1131                 order = flsl(npages) - 1;
 1132                 n = 1 << order;
 1133                 vm_phys_free_pages(m, order);
 1134                 m += n;
 1135         }
 1136 }
 1137 
 1138 /*
 1139  * Scan physical memory between the specified addresses "low" and "high" for a
 1140  * run of contiguous physical pages that satisfy the specified conditions, and
 1141  * return the lowest page in the run.  The specified "alignment" determines
 1142  * the alignment of the lowest physical page in the run.  If the specified
 1143  * "boundary" is non-zero, then the run of physical pages cannot span a
 1144  * physical address that is a multiple of "boundary".
 1145  *
 1146  * "npages" must be greater than zero.  Both "alignment" and "boundary" must
 1147  * be a power of two.
 1148  */
 1149 vm_page_t
 1150 vm_phys_scan_contig(int domain, u_long npages, vm_paddr_t low, vm_paddr_t high,
 1151     u_long alignment, vm_paddr_t boundary, int options)
 1152 {
 1153         vm_paddr_t pa_end;
 1154         vm_page_t m_end, m_run, m_start;
 1155         struct vm_phys_seg *seg;
 1156         int segind;
 1157 
 1158         KASSERT(npages > 0, ("npages is 0"));
 1159         KASSERT(powerof2(alignment), ("alignment is not a power of 2"));
 1160         KASSERT(powerof2(boundary), ("boundary is not a power of 2"));
 1161         if (low >= high)
 1162                 return (NULL);
 1163         for (segind = 0; segind < vm_phys_nsegs; segind++) {
 1164                 seg = &vm_phys_segs[segind];
 1165                 if (seg->domain != domain)
 1166                         continue;
 1167                 if (seg->start >= high)
 1168                         break;
 1169                 if (low >= seg->end)
 1170                         continue;
 1171                 if (low <= seg->start)
 1172                         m_start = seg->first_page;
 1173                 else
 1174                         m_start = &seg->first_page[atop(low - seg->start)];
 1175                 if (high < seg->end)
 1176                         pa_end = high;
 1177                 else
 1178                         pa_end = seg->end;
 1179                 if (pa_end - VM_PAGE_TO_PHYS(m_start) < ptoa(npages))
 1180                         continue;
 1181                 m_end = &seg->first_page[atop(pa_end - seg->start)];
 1182                 m_run = vm_page_scan_contig(npages, m_start, m_end,
 1183                     alignment, boundary, options);
 1184                 if (m_run != NULL)
 1185                         return (m_run);
 1186         }
 1187         return (NULL);
 1188 }
 1189 
 1190 /*
 1191  * Set the pool for a contiguous, power of two-sized set of physical pages. 
 1192  */
 1193 void
 1194 vm_phys_set_pool(int pool, vm_page_t m, int order)
 1195 {
 1196         vm_page_t m_tmp;
 1197 
 1198         for (m_tmp = m; m_tmp < &m[1 << order]; m_tmp++)
 1199                 m_tmp->pool = pool;
 1200 }
 1201 
 1202 /*
 1203  * Search for the given physical page "m" in the free lists.  If the search
 1204  * succeeds, remove "m" from the free lists and return TRUE.  Otherwise, return
 1205  * FALSE, indicating that "m" is not in the free lists.
 1206  *
 1207  * The free page queues must be locked.
 1208  */
 1209 boolean_t
 1210 vm_phys_unfree_page(vm_page_t m)
 1211 {
 1212         struct vm_freelist *fl;
 1213         struct vm_phys_seg *seg;
 1214         vm_paddr_t pa, pa_half;
 1215         vm_page_t m_set, m_tmp;
 1216         int order;
 1217 
 1218         /*
 1219          * First, find the contiguous, power of two-sized set of free
 1220          * physical pages containing the given physical page "m" and
 1221          * assign it to "m_set".
 1222          */
 1223         seg = &vm_phys_segs[m->segind];
 1224         vm_domain_free_assert_locked(VM_DOMAIN(seg->domain));
 1225         for (m_set = m, order = 0; m_set->order == VM_NFREEORDER &&
 1226             order < VM_NFREEORDER - 1; ) {
 1227                 order++;
 1228                 pa = m->phys_addr & (~(vm_paddr_t)0 << (PAGE_SHIFT + order));
 1229                 if (pa >= seg->start)
 1230                         m_set = &seg->first_page[atop(pa - seg->start)];
 1231                 else
 1232                         return (FALSE);
 1233         }
 1234         if (m_set->order < order)
 1235                 return (FALSE);
 1236         if (m_set->order == VM_NFREEORDER)
 1237                 return (FALSE);
 1238         KASSERT(m_set->order < VM_NFREEORDER,
 1239             ("vm_phys_unfree_page: page %p has unexpected order %d",
 1240             m_set, m_set->order));
 1241 
 1242         /*
 1243          * Next, remove "m_set" from the free lists.  Finally, extract
 1244          * "m" from "m_set" using an iterative algorithm: While "m_set"
 1245          * is larger than a page, shrink "m_set" by returning the half
 1246          * of "m_set" that does not contain "m" to the free lists.
 1247          */
 1248         fl = (*seg->free_queues)[m_set->pool];
 1249         order = m_set->order;
 1250         vm_freelist_rem(fl, m_set, order);
 1251         while (order > 0) {
 1252                 order--;
 1253                 pa_half = m_set->phys_addr ^ (1 << (PAGE_SHIFT + order));
 1254                 if (m->phys_addr < pa_half)
 1255                         m_tmp = &seg->first_page[atop(pa_half - seg->start)];
 1256                 else {
 1257                         m_tmp = m_set;
 1258                         m_set = &seg->first_page[atop(pa_half - seg->start)];
 1259                 }
 1260                 vm_freelist_add(fl, m_tmp, order, 0);
 1261         }
 1262         KASSERT(m_set == m, ("vm_phys_unfree_page: fatal inconsistency"));
 1263         return (TRUE);
 1264 }
 1265 
 1266 /*
 1267  * Allocate a contiguous set of physical pages of the given size
 1268  * "npages" from the free lists.  All of the physical pages must be at
 1269  * or above the given physical address "low" and below the given
 1270  * physical address "high".  The given value "alignment" determines the
 1271  * alignment of the first physical page in the set.  If the given value
 1272  * "boundary" is non-zero, then the set of physical pages cannot cross
 1273  * any physical address boundary that is a multiple of that value.  Both
 1274  * "alignment" and "boundary" must be a power of two.
 1275  */
 1276 vm_page_t
 1277 vm_phys_alloc_contig(int domain, u_long npages, vm_paddr_t low, vm_paddr_t high,
 1278     u_long alignment, vm_paddr_t boundary)
 1279 {
 1280         vm_paddr_t pa_end, pa_start;
 1281         vm_page_t m_run;
 1282         struct vm_phys_seg *seg;
 1283         int segind;
 1284 
 1285         KASSERT(npages > 0, ("npages is 0"));
 1286         KASSERT(powerof2(alignment), ("alignment is not a power of 2"));
 1287         KASSERT(powerof2(boundary), ("boundary is not a power of 2"));
 1288         vm_domain_free_assert_locked(VM_DOMAIN(domain));
 1289         if (low >= high)
 1290                 return (NULL);
 1291         m_run = NULL;
 1292         for (segind = vm_phys_nsegs - 1; segind >= 0; segind--) {
 1293                 seg = &vm_phys_segs[segind];
 1294                 if (seg->start >= high || seg->domain != domain)
 1295                         continue;
 1296                 if (low >= seg->end)
 1297                         break;
 1298                 if (low <= seg->start)
 1299                         pa_start = seg->start;
 1300                 else
 1301                         pa_start = low;
 1302                 if (high < seg->end)
 1303                         pa_end = high;
 1304                 else
 1305                         pa_end = seg->end;
 1306                 if (pa_end - pa_start < ptoa(npages))
 1307                         continue;
 1308                 m_run = vm_phys_alloc_seg_contig(seg, npages, low, high,
 1309                     alignment, boundary);
 1310                 if (m_run != NULL)
 1311                         break;
 1312         }
 1313         return (m_run);
 1314 }
 1315 
 1316 /*
 1317  * Allocate a run of contiguous physical pages from the free list for the
 1318  * specified segment.
 1319  */
 1320 static vm_page_t
 1321 vm_phys_alloc_seg_contig(struct vm_phys_seg *seg, u_long npages,
 1322     vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary)
 1323 {
 1324         struct vm_freelist *fl;
 1325         vm_paddr_t pa, pa_end, size;
 1326         vm_page_t m, m_ret;
 1327         u_long npages_end;
 1328         int oind, order, pind;
 1329 
 1330         KASSERT(npages > 0, ("npages is 0"));
 1331         KASSERT(powerof2(alignment), ("alignment is not a power of 2"));
 1332         KASSERT(powerof2(boundary), ("boundary is not a power of 2"));
 1333         vm_domain_free_assert_locked(VM_DOMAIN(seg->domain));
 1334         /* Compute the queue that is the best fit for npages. */
 1335         order = flsl(npages - 1);
 1336         /* Search for a run satisfying the specified conditions. */
 1337         size = npages << PAGE_SHIFT;
 1338         for (oind = min(order, VM_NFREEORDER - 1); oind < VM_NFREEORDER;
 1339             oind++) {
 1340                 for (pind = 0; pind < VM_NFREEPOOL; pind++) {
 1341                         fl = (*seg->free_queues)[pind];
 1342                         TAILQ_FOREACH(m_ret, &fl[oind].pl, listq) {
 1343                                 /*
 1344                                  * Is the size of this allocation request
 1345                                  * larger than the largest block size?
 1346                                  */
 1347                                 if (order >= VM_NFREEORDER) {
 1348                                         /*
 1349                                          * Determine if a sufficient number of
 1350                                          * subsequent blocks to satisfy the
 1351                                          * allocation request are free.
 1352                                          */
 1353                                         pa = VM_PAGE_TO_PHYS(m_ret);
 1354                                         pa_end = pa + size;
 1355                                         if (pa_end < pa)
 1356                                                 continue;
 1357                                         for (;;) {
 1358                                                 pa += 1 << (PAGE_SHIFT +
 1359                                                     VM_NFREEORDER - 1);
 1360                                                 if (pa >= pa_end ||
 1361                                                     pa < seg->start ||
 1362                                                     pa >= seg->end)
 1363                                                         break;
 1364                                                 m = &seg->first_page[atop(pa -
 1365                                                     seg->start)];
 1366                                                 if (m->order != VM_NFREEORDER -
 1367                                                     1)
 1368                                                         break;
 1369                                         }
 1370                                         /* If not, go to the next block. */
 1371                                         if (pa < pa_end)
 1372                                                 continue;
 1373                                 }
 1374 
 1375                                 /*
 1376                                  * Determine if the blocks are within the
 1377                                  * given range, satisfy the given alignment,
 1378                                  * and do not cross the given boundary.
 1379                                  */
 1380                                 pa = VM_PAGE_TO_PHYS(m_ret);
 1381                                 pa_end = pa + size;
 1382                                 if (pa >= low && pa_end <= high &&
 1383                                     (pa & (alignment - 1)) == 0 &&
 1384                                     rounddown2(pa ^ (pa_end - 1), boundary) == 0)
 1385                                         goto done;
 1386                         }
 1387                 }
 1388         }
 1389         return (NULL);
 1390 done:
 1391         for (m = m_ret; m < &m_ret[npages]; m = &m[1 << oind]) {
 1392                 fl = (*seg->free_queues)[m->pool];
 1393                 vm_freelist_rem(fl, m, oind);
 1394                 if (m->pool != VM_FREEPOOL_DEFAULT)
 1395                         vm_phys_set_pool(VM_FREEPOOL_DEFAULT, m, oind);
 1396         }
 1397         /* Return excess pages to the free lists. */
 1398         npages_end = roundup2(npages, 1 << oind);
 1399         if (npages < npages_end) {
 1400                 fl = (*seg->free_queues)[VM_FREEPOOL_DEFAULT];
 1401                 vm_phys_enq_range(&m_ret[npages], npages_end - npages, fl, 0);
 1402         }
 1403         return (m_ret);
 1404 }
 1405 
 1406 #ifdef DDB
 1407 /*
 1408  * Show the number of physical pages in each of the free lists.
 1409  */
 1410 DB_SHOW_COMMAND(freepages, db_show_freepages)
 1411 {
 1412         struct vm_freelist *fl;
 1413         int flind, oind, pind, dom;
 1414 
 1415         for (dom = 0; dom < vm_ndomains; dom++) {
 1416                 db_printf("DOMAIN: %d\n", dom);
 1417                 for (flind = 0; flind < vm_nfreelists; flind++) {
 1418                         db_printf("FREE LIST %d:\n"
 1419                             "\n  ORDER (SIZE)  |  NUMBER"
 1420                             "\n              ", flind);
 1421                         for (pind = 0; pind < VM_NFREEPOOL; pind++)
 1422                                 db_printf("  |  POOL %d", pind);
 1423                         db_printf("\n--            ");
 1424                         for (pind = 0; pind < VM_NFREEPOOL; pind++)
 1425                                 db_printf("-- --      ");
 1426                         db_printf("--\n");
 1427                         for (oind = VM_NFREEORDER - 1; oind >= 0; oind--) {
 1428                                 db_printf("  %2.2d (%6.6dK)", oind,
 1429                                     1 << (PAGE_SHIFT - 10 + oind));
 1430                                 for (pind = 0; pind < VM_NFREEPOOL; pind++) {
 1431                                 fl = vm_phys_free_queues[dom][flind][pind];
 1432                                         db_printf("  |  %6.6d", fl[oind].lcnt);
 1433                                 }
 1434                                 db_printf("\n");
 1435                         }
 1436                         db_printf("\n");
 1437                 }
 1438                 db_printf("\n");
 1439         }
 1440 }
 1441 #endif

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