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FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_phys.c

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    1 /*-
    2  * Copyright (c) 2002-2006 Rice University
    3  * Copyright (c) 2007 Alan L. Cox <alc@cs.rice.edu>
    4  * All rights reserved.
    5  *
    6  * This software was developed for the FreeBSD Project by Alan L. Cox,
    7  * Olivier Crameri, Peter Druschel, Sitaram Iyer, and Juan Navarro.
    8  *
    9  * Redistribution and use in source and binary forms, with or without
   10  * modification, are permitted provided that the following conditions
   11  * are met:
   12  * 1. Redistributions of source code must retain the above copyright
   13  *    notice, this list of conditions and the following disclaimer.
   14  * 2. Redistributions in binary form must reproduce the above copyright
   15  *    notice, this list of conditions and the following disclaimer in the
   16  *    documentation and/or other materials provided with the distribution.
   17  *
   18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   19  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   21  * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT
   22  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   24  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   25  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   26  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
   28  * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   29  * POSSIBILITY OF SUCH DAMAGE.
   30  */
   31 
   32 #include <sys/cdefs.h>
   33 __FBSDID("$FreeBSD: releng/7.3/sys/vm/vm_phys.c 202979 2010-01-25 18:15:10Z jhb $");
   34 
   35 #include "opt_ddb.h"
   36 
   37 #include <sys/param.h>
   38 #include <sys/systm.h>
   39 #include <sys/lock.h>
   40 #include <sys/kernel.h>
   41 #include <sys/malloc.h>
   42 #include <sys/mutex.h>
   43 #include <sys/queue.h>
   44 #include <sys/sbuf.h>
   45 #include <sys/sysctl.h>
   46 #include <sys/vmmeter.h>
   47 #include <sys/vnode.h>
   48 
   49 #include <ddb/ddb.h>
   50 
   51 #include <vm/vm.h>
   52 #include <vm/vm_param.h>
   53 #include <vm/vm_kern.h>
   54 #include <vm/vm_object.h>
   55 #include <vm/vm_page.h>
   56 #include <vm/vm_phys.h>
   57 #include <vm/vm_reserv.h>
   58 
   59 struct vm_freelist {
   60         struct pglist pl;
   61         int lcnt;
   62 };
   63 
   64 struct vm_phys_seg {
   65         vm_paddr_t      start;
   66         vm_paddr_t      end;
   67         vm_page_t       first_page;
   68         struct vm_freelist (*free_queues)[VM_NFREEPOOL][VM_NFREEORDER];
   69 };
   70 
   71 static struct vm_phys_seg vm_phys_segs[VM_PHYSSEG_MAX];
   72 
   73 static int vm_phys_nsegs;
   74 
   75 static struct vm_freelist
   76     vm_phys_free_queues[VM_NFREELIST][VM_NFREEPOOL][VM_NFREEORDER];
   77 
   78 static int vm_nfreelists = VM_FREELIST_DEFAULT + 1;
   79 
   80 static int cnt_prezero;
   81 SYSCTL_INT(_vm_stats_misc, OID_AUTO, cnt_prezero, CTLFLAG_RD,
   82     &cnt_prezero, 0, "The number of physical pages prezeroed at idle time");
   83 
   84 static int sysctl_vm_phys_free(SYSCTL_HANDLER_ARGS);
   85 SYSCTL_OID(_vm, OID_AUTO, phys_free, CTLTYPE_STRING | CTLFLAG_RD,
   86     NULL, 0, sysctl_vm_phys_free, "A", "Phys Free Info");
   87 
   88 static int sysctl_vm_phys_segs(SYSCTL_HANDLER_ARGS);
   89 SYSCTL_OID(_vm, OID_AUTO, phys_segs, CTLTYPE_STRING | CTLFLAG_RD,
   90     NULL, 0, sysctl_vm_phys_segs, "A", "Phys Seg Info");
   91 
   92 static void vm_phys_create_seg(vm_paddr_t start, vm_paddr_t end, int flind);
   93 static int vm_phys_paddr_to_segind(vm_paddr_t pa);
   94 static void vm_phys_split_pages(vm_page_t m, int oind, struct vm_freelist *fl,
   95     int order);
   96 
   97 /*
   98  * Outputs the state of the physical memory allocator, specifically,
   99  * the amount of physical memory in each free list.
  100  */
  101 static int
  102 sysctl_vm_phys_free(SYSCTL_HANDLER_ARGS)
  103 {
  104         struct sbuf sbuf;
  105         struct vm_freelist *fl;
  106         char *cbuf;
  107         const int cbufsize = vm_nfreelists*(VM_NFREEORDER + 1)*81;
  108         int error, flind, oind, pind;
  109 
  110         cbuf = malloc(cbufsize, M_TEMP, M_WAITOK | M_ZERO);
  111         sbuf_new(&sbuf, cbuf, cbufsize, SBUF_FIXEDLEN);
  112         for (flind = 0; flind < vm_nfreelists; flind++) {
  113                 sbuf_printf(&sbuf, "\nFREE LIST %d:\n"
  114                     "\n  ORDER (SIZE)  |  NUMBER"
  115                     "\n              ", flind);
  116                 for (pind = 0; pind < VM_NFREEPOOL; pind++)
  117                         sbuf_printf(&sbuf, "  |  POOL %d", pind);
  118                 sbuf_printf(&sbuf, "\n--            ");
  119                 for (pind = 0; pind < VM_NFREEPOOL; pind++)
  120                         sbuf_printf(&sbuf, "-- --      ");
  121                 sbuf_printf(&sbuf, "--\n");
  122                 for (oind = VM_NFREEORDER - 1; oind >= 0; oind--) {
  123                         sbuf_printf(&sbuf, "  %2.2d (%6.6dK)", oind,
  124                             1 << (PAGE_SHIFT - 10 + oind));
  125                         for (pind = 0; pind < VM_NFREEPOOL; pind++) {
  126                                 fl = vm_phys_free_queues[flind][pind];
  127                                 sbuf_printf(&sbuf, "  |  %6.6d", fl[oind].lcnt);
  128                         }
  129                         sbuf_printf(&sbuf, "\n");
  130                 }
  131         }
  132         sbuf_finish(&sbuf);
  133         error = SYSCTL_OUT(req, sbuf_data(&sbuf), sbuf_len(&sbuf));
  134         sbuf_delete(&sbuf);
  135         free(cbuf, M_TEMP);
  136         return (error);
  137 }
  138 
  139 /*
  140  * Outputs the set of physical memory segments.
  141  */
  142 static int
  143 sysctl_vm_phys_segs(SYSCTL_HANDLER_ARGS)
  144 {
  145         struct sbuf sbuf;
  146         struct vm_phys_seg *seg;
  147         char *cbuf;
  148         const int cbufsize = VM_PHYSSEG_MAX*(VM_NFREEORDER + 1)*81;
  149         int error, segind;
  150 
  151         cbuf = malloc(cbufsize, M_TEMP, M_WAITOK | M_ZERO);
  152         sbuf_new(&sbuf, cbuf, cbufsize, SBUF_FIXEDLEN);
  153         for (segind = 0; segind < vm_phys_nsegs; segind++) {
  154                 sbuf_printf(&sbuf, "\nSEGMENT %d:\n\n", segind);
  155                 seg = &vm_phys_segs[segind];
  156                 sbuf_printf(&sbuf, "start:     %#jx\n",
  157                     (uintmax_t)seg->start);
  158                 sbuf_printf(&sbuf, "end:       %#jx\n",
  159                     (uintmax_t)seg->end);
  160                 sbuf_printf(&sbuf, "free list: %p\n", seg->free_queues);
  161         }
  162         sbuf_finish(&sbuf);
  163         error = SYSCTL_OUT(req, sbuf_data(&sbuf), sbuf_len(&sbuf));
  164         sbuf_delete(&sbuf);
  165         free(cbuf, M_TEMP);
  166         return (error);
  167 }
  168 
  169 /*
  170  * Create a physical memory segment.
  171  */
  172 static void
  173 vm_phys_create_seg(vm_paddr_t start, vm_paddr_t end, int flind)
  174 {
  175         struct vm_phys_seg *seg;
  176 #ifdef VM_PHYSSEG_SPARSE
  177         long pages;
  178         int segind;
  179 
  180         pages = 0;
  181         for (segind = 0; segind < vm_phys_nsegs; segind++) {
  182                 seg = &vm_phys_segs[segind];
  183                 pages += atop(seg->end - seg->start);
  184         }
  185 #endif
  186         KASSERT(vm_phys_nsegs < VM_PHYSSEG_MAX,
  187             ("vm_phys_create_seg: increase VM_PHYSSEG_MAX"));
  188         seg = &vm_phys_segs[vm_phys_nsegs++];
  189         seg->start = start;
  190         seg->end = end;
  191 #ifdef VM_PHYSSEG_SPARSE
  192         seg->first_page = &vm_page_array[pages];
  193 #else
  194         seg->first_page = PHYS_TO_VM_PAGE(start);
  195 #endif
  196         seg->free_queues = &vm_phys_free_queues[flind];
  197 }
  198 
  199 /*
  200  * Initialize the physical memory allocator.
  201  */
  202 void
  203 vm_phys_init(void)
  204 {
  205         struct vm_freelist *fl;
  206         int flind, i, oind, pind;
  207 
  208         for (i = 0; phys_avail[i + 1] != 0; i += 2) {
  209 #ifdef  VM_FREELIST_ISADMA
  210                 if (phys_avail[i] < 16777216) {
  211                         if (phys_avail[i + 1] > 16777216) {
  212                                 vm_phys_create_seg(phys_avail[i], 16777216,
  213                                     VM_FREELIST_ISADMA);
  214                                 vm_phys_create_seg(16777216, phys_avail[i + 1],
  215                                     VM_FREELIST_DEFAULT);
  216                         } else {
  217                                 vm_phys_create_seg(phys_avail[i],
  218                                     phys_avail[i + 1], VM_FREELIST_ISADMA);
  219                         }
  220                         if (VM_FREELIST_ISADMA >= vm_nfreelists)
  221                                 vm_nfreelists = VM_FREELIST_ISADMA + 1;
  222                 } else
  223 #endif
  224 #ifdef  VM_FREELIST_HIGHMEM
  225                 if (phys_avail[i + 1] > VM_HIGHMEM_ADDRESS) {
  226                         if (phys_avail[i] < VM_HIGHMEM_ADDRESS) {
  227                                 vm_phys_create_seg(phys_avail[i],
  228                                     VM_HIGHMEM_ADDRESS, VM_FREELIST_DEFAULT);
  229                                 vm_phys_create_seg(VM_HIGHMEM_ADDRESS,
  230                                     phys_avail[i + 1], VM_FREELIST_HIGHMEM);
  231                         } else {
  232                                 vm_phys_create_seg(phys_avail[i],
  233                                     phys_avail[i + 1], VM_FREELIST_HIGHMEM);
  234                         }
  235                         if (VM_FREELIST_HIGHMEM >= vm_nfreelists)
  236                                 vm_nfreelists = VM_FREELIST_HIGHMEM + 1;
  237                 } else
  238 #endif
  239                 vm_phys_create_seg(phys_avail[i], phys_avail[i + 1],
  240                     VM_FREELIST_DEFAULT);
  241         }
  242         for (flind = 0; flind < vm_nfreelists; flind++) {
  243                 for (pind = 0; pind < VM_NFREEPOOL; pind++) {
  244                         fl = vm_phys_free_queues[flind][pind];
  245                         for (oind = 0; oind < VM_NFREEORDER; oind++)
  246                                 TAILQ_INIT(&fl[oind].pl);
  247                 }
  248         }
  249 }
  250 
  251 /*
  252  * Split a contiguous, power of two-sized set of physical pages.
  253  */
  254 static __inline void
  255 vm_phys_split_pages(vm_page_t m, int oind, struct vm_freelist *fl, int order)
  256 {
  257         vm_page_t m_buddy;
  258 
  259         while (oind > order) {
  260                 oind--;
  261                 m_buddy = &m[1 << oind];
  262                 KASSERT(m_buddy->order == VM_NFREEORDER,
  263                     ("vm_phys_split_pages: page %p has unexpected order %d",
  264                     m_buddy, m_buddy->order));
  265                 m_buddy->order = oind;
  266                 TAILQ_INSERT_HEAD(&fl[oind].pl, m_buddy, pageq);
  267                 fl[oind].lcnt++;
  268         }
  269 }
  270 
  271 /*
  272  * Initialize a physical page and add it to the free lists.
  273  */
  274 void
  275 vm_phys_add_page(vm_paddr_t pa)
  276 {
  277         vm_page_t m;
  278 
  279         cnt.v_page_count++;
  280         m = vm_phys_paddr_to_vm_page(pa);
  281         m->phys_addr = pa;
  282         m->segind = vm_phys_paddr_to_segind(pa);
  283         m->flags = PG_FREE;
  284         KASSERT(m->order == VM_NFREEORDER,
  285             ("vm_phys_add_page: page %p has unexpected order %d",
  286             m, m->order));
  287         m->pool = VM_FREEPOOL_DEFAULT;
  288         pmap_page_init(m);
  289         mtx_lock(&vm_page_queue_free_mtx);
  290         cnt.v_free_count++;
  291         vm_phys_free_pages(m, 0);
  292         mtx_unlock(&vm_page_queue_free_mtx);
  293 }
  294 
  295 /*
  296  * Allocate a contiguous, power of two-sized set of physical pages
  297  * from the free lists.
  298  *
  299  * The free page queues must be locked.
  300  */
  301 vm_page_t
  302 vm_phys_alloc_pages(int pool, int order)
  303 {
  304         struct vm_freelist *fl;
  305         struct vm_freelist *alt;
  306         int flind, oind, pind;
  307         vm_page_t m;
  308 
  309         KASSERT(pool < VM_NFREEPOOL,
  310             ("vm_phys_alloc_pages: pool %d is out of range", pool));
  311         KASSERT(order < VM_NFREEORDER,
  312             ("vm_phys_alloc_pages: order %d is out of range", order));
  313         mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
  314         for (flind = 0; flind < vm_nfreelists; flind++) {
  315                 fl = vm_phys_free_queues[flind][pool];
  316                 for (oind = order; oind < VM_NFREEORDER; oind++) {
  317                         m = TAILQ_FIRST(&fl[oind].pl);
  318                         if (m != NULL) {
  319                                 TAILQ_REMOVE(&fl[oind].pl, m, pageq);
  320                                 fl[oind].lcnt--;
  321                                 m->order = VM_NFREEORDER;
  322                                 vm_phys_split_pages(m, oind, fl, order);
  323                                 return (m);
  324                         }
  325                 }
  326 
  327                 /*
  328                  * The given pool was empty.  Find the largest
  329                  * contiguous, power-of-two-sized set of pages in any
  330                  * pool.  Transfer these pages to the given pool, and
  331                  * use them to satisfy the allocation.
  332                  */
  333                 for (oind = VM_NFREEORDER - 1; oind >= order; oind--) {
  334                         for (pind = 0; pind < VM_NFREEPOOL; pind++) {
  335                                 alt = vm_phys_free_queues[flind][pind];
  336                                 m = TAILQ_FIRST(&alt[oind].pl);
  337                                 if (m != NULL) {
  338                                         TAILQ_REMOVE(&alt[oind].pl, m, pageq);
  339                                         alt[oind].lcnt--;
  340                                         m->order = VM_NFREEORDER;
  341                                         vm_phys_set_pool(pool, m, oind);
  342                                         vm_phys_split_pages(m, oind, fl, order);
  343                                         return (m);
  344                                 }
  345                         }
  346                 }
  347         }
  348         return (NULL);
  349 }
  350 
  351 /*
  352  * Allocate physical memory from phys_avail[].
  353  */
  354 vm_paddr_t
  355 vm_phys_bootstrap_alloc(vm_size_t size, unsigned long alignment)
  356 {
  357         vm_paddr_t pa;
  358         int i;
  359 
  360         size = round_page(size);
  361         for (i = 0; phys_avail[i + 1] != 0; i += 2) {
  362                 if (phys_avail[i + 1] - phys_avail[i] < size)
  363                         continue;
  364                 pa = phys_avail[i];
  365                 phys_avail[i] += size;
  366                 return (pa);
  367         }
  368         panic("vm_phys_bootstrap_alloc");
  369 }
  370 
  371 /*
  372  * Find the vm_page corresponding to the given physical address.
  373  */
  374 vm_page_t
  375 vm_phys_paddr_to_vm_page(vm_paddr_t pa)
  376 {
  377         struct vm_phys_seg *seg;
  378         int segind;
  379 
  380         for (segind = 0; segind < vm_phys_nsegs; segind++) {
  381                 seg = &vm_phys_segs[segind];
  382                 if (pa >= seg->start && pa < seg->end)
  383                         return (&seg->first_page[atop(pa - seg->start)]);
  384         }
  385         return (NULL);
  386 }
  387 
  388 /*
  389  * Find the segment containing the given physical address.
  390  */
  391 static int
  392 vm_phys_paddr_to_segind(vm_paddr_t pa)
  393 {
  394         struct vm_phys_seg *seg;
  395         int segind;
  396 
  397         for (segind = 0; segind < vm_phys_nsegs; segind++) {
  398                 seg = &vm_phys_segs[segind];
  399                 if (pa >= seg->start && pa < seg->end)
  400                         return (segind);
  401         }
  402         panic("vm_phys_paddr_to_segind: paddr %#jx is not in any segment" ,
  403             (uintmax_t)pa);
  404 }
  405 
  406 /*
  407  * Free a contiguous, power of two-sized set of physical pages.
  408  *
  409  * The free page queues must be locked.
  410  */
  411 void
  412 vm_phys_free_pages(vm_page_t m, int order)
  413 {
  414         struct vm_freelist *fl;
  415         struct vm_phys_seg *seg;
  416         vm_paddr_t pa, pa_buddy;
  417         vm_page_t m_buddy;
  418 
  419         KASSERT(m->order == VM_NFREEORDER,
  420             ("vm_phys_free_pages: page %p has unexpected order %d",
  421             m, m->order));
  422         KASSERT(m->pool < VM_NFREEPOOL,
  423             ("vm_phys_free_pages: page %p has unexpected pool %d",
  424             m, m->pool));
  425         KASSERT(order < VM_NFREEORDER,
  426             ("vm_phys_free_pages: order %d is out of range", order));
  427         mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
  428         pa = VM_PAGE_TO_PHYS(m);
  429         seg = &vm_phys_segs[m->segind];
  430         while (order < VM_NFREEORDER - 1) {
  431                 pa_buddy = pa ^ (1 << (PAGE_SHIFT + order));
  432                 if (pa_buddy < seg->start ||
  433                     pa_buddy >= seg->end)
  434                         break;
  435                 m_buddy = &seg->first_page[atop(pa_buddy - seg->start)];
  436                 if (m_buddy->order != order)
  437                         break;
  438                 fl = (*seg->free_queues)[m_buddy->pool];
  439                 TAILQ_REMOVE(&fl[m_buddy->order].pl, m_buddy, pageq);
  440                 fl[m_buddy->order].lcnt--;
  441                 m_buddy->order = VM_NFREEORDER;
  442                 if (m_buddy->pool != m->pool)
  443                         vm_phys_set_pool(m->pool, m_buddy, order);
  444                 order++;
  445                 pa &= ~((1 << (PAGE_SHIFT + order)) - 1);
  446                 m = &seg->first_page[atop(pa - seg->start)];
  447         }
  448         m->order = order;
  449         fl = (*seg->free_queues)[m->pool];
  450         TAILQ_INSERT_TAIL(&fl[order].pl, m, pageq);
  451         fl[order].lcnt++;
  452 }
  453 
  454 /*
  455  * Set the pool for a contiguous, power of two-sized set of physical pages. 
  456  */
  457 void
  458 vm_phys_set_pool(int pool, vm_page_t m, int order)
  459 {
  460         vm_page_t m_tmp;
  461 
  462         for (m_tmp = m; m_tmp < &m[1 << order]; m_tmp++)
  463                 m_tmp->pool = pool;
  464 }
  465 
  466 /*
  467  * Search for the given physical page "m" in the free lists.  If the search
  468  * succeeds, remove "m" from the free lists and return TRUE.  Otherwise, return
  469  * FALSE, indicating that "m" is not in the free lists.
  470  *
  471  * The free page queues must be locked.
  472  */
  473 boolean_t
  474 vm_phys_unfree_page(vm_page_t m)
  475 {
  476         struct vm_freelist *fl;
  477         struct vm_phys_seg *seg;
  478         vm_paddr_t pa, pa_half;
  479         vm_page_t m_set, m_tmp;
  480         int order;
  481 
  482         mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
  483 
  484         /*
  485          * First, find the contiguous, power of two-sized set of free
  486          * physical pages containing the given physical page "m" and
  487          * assign it to "m_set".
  488          */
  489         seg = &vm_phys_segs[m->segind];
  490         for (m_set = m, order = 0; m_set->order == VM_NFREEORDER &&
  491             order < VM_NFREEORDER - 1; ) {
  492                 order++;
  493                 pa = m->phys_addr & (~(vm_paddr_t)0 << (PAGE_SHIFT + order));
  494                 if (pa >= seg->start)
  495                         m_set = &seg->first_page[atop(pa - seg->start)];
  496                 else
  497                         return (FALSE);
  498         }
  499         if (m_set->order < order)
  500                 return (FALSE);
  501         if (m_set->order == VM_NFREEORDER)
  502                 return (FALSE);
  503         KASSERT(m_set->order < VM_NFREEORDER,
  504             ("vm_phys_unfree_page: page %p has unexpected order %d",
  505             m_set, m_set->order));
  506 
  507         /*
  508          * Next, remove "m_set" from the free lists.  Finally, extract
  509          * "m" from "m_set" using an iterative algorithm: While "m_set"
  510          * is larger than a page, shrink "m_set" by returning the half
  511          * of "m_set" that does not contain "m" to the free lists.
  512          */
  513         fl = (*seg->free_queues)[m_set->pool];
  514         order = m_set->order;
  515         TAILQ_REMOVE(&fl[order].pl, m_set, pageq);
  516         fl[order].lcnt--;
  517         m_set->order = VM_NFREEORDER;
  518         while (order > 0) {
  519                 order--;
  520                 pa_half = m_set->phys_addr ^ (1 << (PAGE_SHIFT + order));
  521                 if (m->phys_addr < pa_half)
  522                         m_tmp = &seg->first_page[atop(pa_half - seg->start)];
  523                 else {
  524                         m_tmp = m_set;
  525                         m_set = &seg->first_page[atop(pa_half - seg->start)];
  526                 }
  527                 m_tmp->order = order;
  528                 TAILQ_INSERT_HEAD(&fl[order].pl, m_tmp, pageq);
  529                 fl[order].lcnt++;
  530         }
  531         KASSERT(m_set == m, ("vm_phys_unfree_page: fatal inconsistency"));
  532         return (TRUE);
  533 }
  534 
  535 /*
  536  * Try to zero one physical page.  Used by an idle priority thread.
  537  */
  538 boolean_t
  539 vm_phys_zero_pages_idle(void)
  540 {
  541         static struct vm_freelist *fl = vm_phys_free_queues[0][0];
  542         static int flind, oind, pind;
  543         vm_page_t m, m_tmp;
  544 
  545         mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
  546         for (;;) {
  547                 TAILQ_FOREACH_REVERSE(m, &fl[oind].pl, pglist, pageq) {
  548                         for (m_tmp = m; m_tmp < &m[1 << oind]; m_tmp++) {
  549                                 if ((m_tmp->flags & (PG_CACHED | PG_ZERO)) == 0) {
  550                                         vm_phys_unfree_page(m_tmp);
  551                                         cnt.v_free_count--;
  552                                         mtx_unlock(&vm_page_queue_free_mtx);
  553                                         pmap_zero_page_idle(m_tmp);
  554                                         m_tmp->flags |= PG_ZERO;
  555                                         mtx_lock(&vm_page_queue_free_mtx);
  556                                         cnt.v_free_count++;
  557                                         vm_phys_free_pages(m_tmp, 0);
  558                                         vm_page_zero_count++;
  559                                         cnt_prezero++;
  560                                         return (TRUE);
  561                                 }
  562                         }
  563                 }
  564                 oind++;
  565                 if (oind == VM_NFREEORDER) {
  566                         oind = 0;
  567                         pind++;
  568                         if (pind == VM_NFREEPOOL) {
  569                                 pind = 0;
  570                                 flind++;
  571                                 if (flind == vm_nfreelists)
  572                                         flind = 0;
  573                         }
  574                         fl = vm_phys_free_queues[flind][pind];
  575                 }
  576         }
  577 }
  578 
  579 /*
  580  * Allocate a contiguous set of physical pages of the given size
  581  * "npages" from the free lists.  All of the physical pages must be at
  582  * or above the given physical address "low" and below the given
  583  * physical address "high".  The given value "alignment" determines the
  584  * alignment of the first physical page in the set.  If the given value
  585  * "boundary" is non-zero, then the set of physical pages cannot cross
  586  * any physical address boundary that is a multiple of that value.  Both
  587  * "alignment" and "boundary" must be a power of two.
  588  */
  589 vm_page_t
  590 vm_phys_alloc_contig(unsigned long npages, vm_paddr_t low, vm_paddr_t high,
  591     unsigned long alignment, unsigned long boundary)
  592 {
  593         struct vm_freelist *fl;
  594         struct vm_phys_seg *seg;
  595         vm_object_t m_object;
  596         vm_paddr_t pa, pa_last, size;
  597         vm_page_t deferred_vdrop_list, m, m_ret;
  598         int flind, i, oind, order, pind;
  599 
  600         size = npages << PAGE_SHIFT;
  601         KASSERT(size != 0,
  602             ("vm_phys_alloc_contig: size must not be 0"));
  603         KASSERT((alignment & (alignment - 1)) == 0,
  604             ("vm_phys_alloc_contig: alignment must be a power of 2"));
  605         KASSERT((boundary & (boundary - 1)) == 0,
  606             ("vm_phys_alloc_contig: boundary must be a power of 2"));
  607         deferred_vdrop_list = NULL;
  608         /* Compute the queue that is the best fit for npages. */
  609         for (order = 0; (1 << order) < npages; order++);
  610         mtx_lock(&vm_page_queue_free_mtx);
  611 #if VM_NRESERVLEVEL > 0
  612 retry:
  613 #endif
  614         for (flind = 0; flind < vm_nfreelists; flind++) {
  615                 for (oind = min(order, VM_NFREEORDER - 1); oind < VM_NFREEORDER; oind++) {
  616                         for (pind = 0; pind < VM_NFREEPOOL; pind++) {
  617                                 fl = vm_phys_free_queues[flind][pind];
  618                                 TAILQ_FOREACH(m_ret, &fl[oind].pl, pageq) {
  619                                         /*
  620                                          * A free list may contain physical pages
  621                                          * from one or more segments.
  622                                          */
  623                                         seg = &vm_phys_segs[m_ret->segind];
  624                                         if (seg->start > high ||
  625                                             low >= seg->end)
  626                                                 continue;
  627 
  628                                         /*
  629                                          * Is the size of this allocation request
  630                                          * larger than the largest block size?
  631                                          */
  632                                         if (order >= VM_NFREEORDER) {
  633                                                 /*
  634                                                  * Determine if a sufficient number
  635                                                  * of subsequent blocks to satisfy
  636                                                  * the allocation request are free.
  637                                                  */
  638                                                 pa = VM_PAGE_TO_PHYS(m_ret);
  639                                                 pa_last = pa + size;
  640                                                 for (;;) {
  641                                                         pa += 1 << (PAGE_SHIFT + VM_NFREEORDER - 1);
  642                                                         if (pa >= pa_last)
  643                                                                 break;
  644                                                         if (pa < seg->start ||
  645                                                             pa >= seg->end)
  646                                                                 break;
  647                                                         m = &seg->first_page[atop(pa - seg->start)];
  648                                                         if (m->order != VM_NFREEORDER - 1)
  649                                                                 break;
  650                                                 }
  651                                                 /* If not, continue to the next block. */
  652                                                 if (pa < pa_last)
  653                                                         continue;
  654                                         }
  655 
  656                                         /*
  657                                          * Determine if the blocks are within the given range,
  658                                          * satisfy the given alignment, and do not cross the
  659                                          * given boundary.
  660                                          */
  661                                         pa = VM_PAGE_TO_PHYS(m_ret);
  662                                         if (pa >= low &&
  663                                             pa + size <= high &&
  664                                             (pa & (alignment - 1)) == 0 &&
  665                                             ((pa ^ (pa + size - 1)) & ~(boundary - 1)) == 0)
  666                                                 goto done;
  667                                 }
  668                         }
  669                 }
  670         }
  671 #if VM_NRESERVLEVEL > 0
  672         if (vm_reserv_reclaim_contig(size, low, high, alignment, boundary))
  673                 goto retry;
  674 #endif
  675         mtx_unlock(&vm_page_queue_free_mtx);
  676         return (NULL);
  677 done:
  678         for (m = m_ret; m < &m_ret[npages]; m = &m[1 << oind]) {
  679                 fl = (*seg->free_queues)[m->pool];
  680                 TAILQ_REMOVE(&fl[m->order].pl, m, pageq);
  681                 fl[m->order].lcnt--;
  682                 m->order = VM_NFREEORDER;
  683         }
  684         if (m_ret->pool != VM_FREEPOOL_DEFAULT)
  685                 vm_phys_set_pool(VM_FREEPOOL_DEFAULT, m_ret, oind);
  686         fl = (*seg->free_queues)[m_ret->pool];
  687         vm_phys_split_pages(m_ret, oind, fl, order);
  688         for (i = 0; i < npages; i++) {
  689                 m = &m_ret[i];
  690                 KASSERT(m->queue == PQ_NONE,
  691                     ("vm_phys_alloc_contig: page %p has unexpected queue %d",
  692                     m, m->queue));
  693                 KASSERT(m->wire_count == 0,
  694                     ("vm_phys_alloc_contig: page %p is wired", m));
  695                 KASSERT(m->hold_count == 0,
  696                     ("vm_phys_alloc_contig: page %p is held", m));
  697                 KASSERT(m->busy == 0,
  698                     ("vm_phys_alloc_contig: page %p is busy", m));
  699                 KASSERT(m->dirty == 0,
  700                     ("vm_phys_alloc_contig: page %p is dirty", m));
  701                 KASSERT(pmap_page_get_memattr(m) == VM_MEMATTR_DEFAULT,
  702                     ("vm_phys_alloc_contig: page %p has unexpected memattr %d",
  703                     m, pmap_page_get_memattr(m)));
  704                 if ((m->flags & PG_CACHED) != 0) {
  705                         m->valid = 0;
  706                         m_object = m->object;
  707                         vm_page_cache_remove(m);
  708                         if (m_object->type == OBJT_VNODE &&
  709                             m_object->cache == NULL) {
  710                                 /*
  711                                  * Enqueue the vnode for deferred vdrop().
  712                                  *
  713                                  * Unmanaged pages don't use "pageq", so it
  714                                  * can be safely abused to construct a short-
  715                                  * lived queue of vnodes.
  716                                  */
  717                                 m->pageq.tqe_prev = m_object->handle;
  718                                 m->pageq.tqe_next = deferred_vdrop_list;
  719                                 deferred_vdrop_list = m;
  720                         }
  721                 } else {
  722                         KASSERT(VM_PAGE_IS_FREE(m),
  723                             ("vm_phys_alloc_contig: page %p is not free", m));
  724                         KASSERT(m->valid == 0,
  725                             ("vm_phys_alloc_contig: free page %p is valid", m));
  726                         cnt.v_free_count--;
  727                 }
  728                 if (m->flags & PG_ZERO)
  729                         vm_page_zero_count--;
  730                 /* Don't clear the PG_ZERO flag; we'll need it later. */
  731                 m->flags = PG_UNMANAGED | (m->flags & PG_ZERO);
  732                 m->oflags = 0;
  733                 /* Unmanaged pages don't use "act_count". */
  734         }
  735         for (; i < roundup2(npages, 1 << imin(oind, order)); i++) {
  736                 m = &m_ret[i];
  737                 KASSERT(m->order == VM_NFREEORDER,
  738                     ("vm_phys_alloc_contig: page %p has unexpected order %d",
  739                     m, m->order));
  740                 vm_phys_free_pages(m, 0);
  741         }
  742         mtx_unlock(&vm_page_queue_free_mtx);
  743         while (deferred_vdrop_list != NULL) {
  744                 vdrop((struct vnode *)deferred_vdrop_list->pageq.tqe_prev);
  745                 deferred_vdrop_list = deferred_vdrop_list->pageq.tqe_next;
  746         }
  747         return (m_ret);
  748 }
  749 
  750 #ifdef DDB
  751 /*
  752  * Show the number of physical pages in each of the free lists.
  753  */
  754 DB_SHOW_COMMAND(freepages, db_show_freepages)
  755 {
  756         struct vm_freelist *fl;
  757         int flind, oind, pind;
  758 
  759         for (flind = 0; flind < vm_nfreelists; flind++) {
  760                 db_printf("FREE LIST %d:\n"
  761                     "\n  ORDER (SIZE)  |  NUMBER"
  762                     "\n              ", flind);
  763                 for (pind = 0; pind < VM_NFREEPOOL; pind++)
  764                         db_printf("  |  POOL %d", pind);
  765                 db_printf("\n--            ");
  766                 for (pind = 0; pind < VM_NFREEPOOL; pind++)
  767                         db_printf("-- --      ");
  768                 db_printf("--\n");
  769                 for (oind = VM_NFREEORDER - 1; oind >= 0; oind--) {
  770                         db_printf("  %2.2d (%6.6dK)", oind,
  771                             1 << (PAGE_SHIFT - 10 + oind));
  772                         for (pind = 0; pind < VM_NFREEPOOL; pind++) {
  773                                 fl = vm_phys_free_queues[flind][pind];
  774                                 db_printf("  |  %6.6d", fl[oind].lcnt);
  775                         }
  776                         db_printf("\n");
  777                 }
  778                 db_printf("\n");
  779         }
  780 }
  781 #endif

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