The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

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

Version: -  FREEBSD  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-2  -  FREEBSD-11-1  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-4  -  FREEBSD-10-3  -  FREEBSD-10-2  -  FREEBSD-10-1  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-3  -  FREEBSD-9-2  -  FREEBSD-9-1  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-4  -  FREEBSD-8-3  -  FREEBSD-8-2  -  FREEBSD-8-1  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-4  -  FREEBSD-7-3  -  FREEBSD-7-2  -  FREEBSD-7-1  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-4  -  FREEBSD-6-3  -  FREEBSD-6-2  -  FREEBSD-6-1  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-5  -  FREEBSD-5-4  -  FREEBSD-5-3  -  FREEBSD-5-2  -  FREEBSD-5-1  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    1 /*
    2  * Copyright (c) 1991, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  *
    5  * This code is derived from software contributed to Berkeley by
    6  * The Mach Operating System project at Carnegie-Mellon University.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  * 3. All advertising materials mentioning features or use of this software
   17  *    must display the following acknowledgement:
   18  *      This product includes software developed by the University of
   19  *      California, Berkeley and its contributors.
   20  * 4. Neither the name of the University nor the names of its contributors
   21  *    may be used to endorse or promote products derived from this software
   22  *    without specific prior written permission.
   23  *
   24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   34  * SUCH DAMAGE.
   35  *
   36  *      from: @(#)vm_kern.c     8.3 (Berkeley) 1/12/94
   37  *
   38  *
   39  * Copyright (c) 1987, 1990 Carnegie-Mellon University.
   40  * All rights reserved.
   41  *
   42  * Authors: Avadis Tevanian, Jr., Michael Wayne Young
   43  *
   44  * Permission to use, copy, modify and distribute this software and
   45  * its documentation is hereby granted, provided that both the copyright
   46  * notice and this permission notice appear in all copies of the
   47  * software, derivative works or modified versions, and any portions
   48  * thereof, and that both notices appear in supporting documentation.
   49  *
   50  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
   51  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
   52  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
   53  *
   54  * Carnegie Mellon requests users of this software to return to
   55  *
   56  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
   57  *  School of Computer Science
   58  *  Carnegie Mellon University
   59  *  Pittsburgh PA 15213-3890
   60  *
   61  * any improvements or extensions that they make and grant Carnegie the
   62  * rights to redistribute these changes.
   63  *
   64  * $FreeBSD: stable/4/sys/vm/vm_kern.c 118695 2003-08-09 16:21:21Z luoqi $
   65  */
   66 
   67 /*
   68  *      Kernel memory management.
   69  */
   70 
   71 #include <sys/param.h>
   72 #include <sys/systm.h>
   73 #include <sys/proc.h>
   74 #include <sys/malloc.h>
   75 
   76 #include <vm/vm.h>
   77 #include <vm/vm_param.h>
   78 #include <sys/lock.h>
   79 #include <vm/pmap.h>
   80 #include <vm/vm_map.h>
   81 #include <vm/vm_object.h>
   82 #include <vm/vm_page.h>
   83 #include <vm/vm_pageout.h>
   84 #include <vm/vm_extern.h>
   85 
   86 vm_map_t kernel_map=0;
   87 vm_map_t kmem_map=0;
   88 vm_map_t exec_map=0;
   89 vm_map_t clean_map=0;
   90 vm_map_t buffer_map=0;
   91 vm_map_t mb_map=0;
   92 int mb_map_full=0;
   93 
   94 /*
   95  *      kmem_alloc_pageable:
   96  *
   97  *      Allocate pageable memory to the kernel's address map.
   98  *      "map" must be kernel_map or a submap of kernel_map.
   99  */
  100 
  101 vm_offset_t
  102 kmem_alloc_pageable(map, size)
  103         vm_map_t map;
  104         register vm_size_t size;
  105 {
  106         vm_offset_t addr;
  107         register int result;
  108 
  109         size = round_page(size);
  110         addr = vm_map_min(map);
  111         result = vm_map_find(map, NULL, (vm_offset_t) 0,
  112             &addr, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, 0);
  113         if (result != KERN_SUCCESS) {
  114                 return (0);
  115         }
  116         return (addr);
  117 }
  118 
  119 /*
  120  *      kmem_alloc_nofault:
  121  *
  122  *      Same as kmem_alloc_pageable, except that it create a nofault entry.
  123  */
  124 
  125 vm_offset_t
  126 kmem_alloc_nofault(map, size)
  127         vm_map_t map;
  128         register vm_size_t size;
  129 {
  130         vm_offset_t addr;
  131         register int result;
  132 
  133         size = round_page(size);
  134         addr = vm_map_min(map);
  135         result = vm_map_find(map, NULL, (vm_offset_t) 0,
  136             &addr, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT);
  137         if (result != KERN_SUCCESS) {
  138                 return (0);
  139         }
  140         return (addr);
  141 }
  142 
  143 /*
  144  *      Allocate wired-down memory in the kernel's address map
  145  *      or a submap.
  146  */
  147 vm_offset_t
  148 kmem_alloc(map, size)
  149         register vm_map_t map;
  150         register vm_size_t size;
  151 {
  152         vm_offset_t addr;
  153         register vm_offset_t offset;
  154         vm_offset_t i;
  155 
  156         size = round_page(size);
  157 
  158         /*
  159          * Use the kernel object for wired-down kernel pages. Assume that no
  160          * region of the kernel object is referenced more than once.
  161          */
  162 
  163         /*
  164          * Locate sufficient space in the map.  This will give us the final
  165          * virtual address for the new memory, and thus will tell us the
  166          * offset within the kernel map.
  167          */
  168         vm_map_lock(map);
  169         if (vm_map_findspace(map, vm_map_min(map), size, &addr)) {
  170                 vm_map_unlock(map);
  171                 return (0);
  172         }
  173         offset = addr - VM_MIN_KERNEL_ADDRESS;
  174         vm_object_reference(kernel_object);
  175         vm_map_insert(map, kernel_object, offset, addr, addr + size,
  176                 VM_PROT_ALL, VM_PROT_ALL, 0);
  177         vm_map_unlock(map);
  178 
  179         /*
  180          * Guarantee that there are pages already in this object before
  181          * calling vm_map_pageable.  This is to prevent the following
  182          * scenario:
  183          *
  184          * 1) Threads have swapped out, so that there is a pager for the
  185          * kernel_object. 2) The kmsg zone is empty, and so we are
  186          * kmem_allocing a new page for it. 3) vm_map_pageable calls vm_fault;
  187          * there is no page, but there is a pager, so we call
  188          * pager_data_request.  But the kmsg zone is empty, so we must
  189          * kmem_alloc. 4) goto 1 5) Even if the kmsg zone is not empty: when
  190          * we get the data back from the pager, it will be (very stale)
  191          * non-zero data.  kmem_alloc is defined to return zero-filled memory.
  192          *
  193          * We're intentionally not activating the pages we allocate to prevent a
  194          * race with page-out.  vm_map_pageable will wire the pages.
  195          */
  196 
  197         for (i = 0; i < size; i += PAGE_SIZE) {
  198                 vm_page_t mem;
  199 
  200                 mem = vm_page_grab(kernel_object, OFF_TO_IDX(offset + i),
  201                                 VM_ALLOC_ZERO | VM_ALLOC_RETRY);
  202                 if ((mem->flags & PG_ZERO) == 0)
  203                         vm_page_zero_fill(mem);
  204                 mem->valid = VM_PAGE_BITS_ALL;
  205                 vm_page_flag_clear(mem, PG_ZERO);
  206                 vm_page_wakeup(mem);
  207         }
  208 
  209         /*
  210          * And finally, mark the data as non-pageable.
  211          */
  212 
  213         (void) vm_map_pageable(map, (vm_offset_t) addr, addr + size, FALSE);
  214 
  215         return (addr);
  216 }
  217 
  218 /*
  219  *      kmem_free:
  220  *
  221  *      Release a region of kernel virtual memory allocated
  222  *      with kmem_alloc, and return the physical pages
  223  *      associated with that region.
  224  *
  225  *      This routine may not block on kernel maps.
  226  */
  227 void
  228 kmem_free(map, addr, size)
  229         vm_map_t map;
  230         register vm_offset_t addr;
  231         vm_size_t size;
  232 {
  233         (void) vm_map_remove(map, trunc_page(addr), round_page(addr + size));
  234 }
  235 
  236 /*
  237  *      kmem_suballoc:
  238  *
  239  *      Allocates a map to manage a subrange
  240  *      of the kernel virtual address space.
  241  *
  242  *      Arguments are as follows:
  243  *
  244  *      parent          Map to take range from
  245  *      size            Size of range to find
  246  *      min, max        Returned endpoints of map
  247  *      pageable        Can the region be paged
  248  */
  249 vm_map_t
  250 kmem_suballoc(parent, min, max, size)
  251         register vm_map_t parent;
  252         vm_offset_t *min, *max;
  253         register vm_size_t size;
  254 {
  255         register int ret;
  256         vm_map_t result;
  257 
  258         size = round_page(size);
  259 
  260         *min = (vm_offset_t) vm_map_min(parent);
  261         ret = vm_map_find(parent, NULL, (vm_offset_t) 0,
  262             min, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, 0);
  263         if (ret != KERN_SUCCESS) {
  264                 printf("kmem_suballoc: bad status return of %d.\n", ret);
  265                 panic("kmem_suballoc");
  266         }
  267         *max = *min + size;
  268         result = vm_map_create(vm_map_pmap(parent), *min, *max);
  269         if (result == NULL)
  270                 panic("kmem_suballoc: cannot create submap");
  271         if ((ret = vm_map_submap(parent, *min, *max, result)) != KERN_SUCCESS)
  272                 panic("kmem_suballoc: unable to change range to submap");
  273         return (result);
  274 }
  275 
  276 /*
  277  *      kmem_malloc:
  278  *
  279  *      Allocate wired-down memory in the kernel's address map for the higher
  280  *      level kernel memory allocator (kern/kern_malloc.c).  We cannot use
  281  *      kmem_alloc() because we may need to allocate memory at interrupt
  282  *      level where we cannot block (canwait == FALSE).
  283  *
  284  *      This routine has its own private kernel submap (kmem_map) and object
  285  *      (kmem_object).  This, combined with the fact that only malloc uses
  286  *      this routine, ensures that we will never block in map or object waits.
  287  *
  288  *      Note that this still only works in a uni-processor environment and
  289  *      when called at splhigh().
  290  *
  291  *      We don't worry about expanding the map (adding entries) since entries
  292  *      for wired maps are statically allocated.
  293  *
  294  *      NOTE:  This routine is not supposed to block if M_NOWAIT is set, but
  295  *      I have not verified that it actually does not block.
  296  */
  297 vm_offset_t
  298 kmem_malloc(map, size, flags)
  299         register vm_map_t map;
  300         register vm_size_t size;
  301         int flags;
  302 {
  303         register vm_offset_t offset, i;
  304         vm_map_entry_t entry;
  305         vm_offset_t addr;
  306         vm_page_t m;
  307 
  308         if (map != kmem_map && map != mb_map)
  309                 panic("kmem_malloc: map != {kmem,mb}_map");
  310 
  311         size = round_page(size);
  312         addr = vm_map_min(map);
  313 
  314         /*
  315          * Locate sufficient space in the map.  This will give us the final
  316          * virtual address for the new memory, and thus will tell us the
  317          * offset within the kernel map.
  318          */
  319         vm_map_lock(map);
  320         if (vm_map_findspace(map, vm_map_min(map), size, &addr)) {
  321                 vm_map_unlock(map);
  322                 if (map == mb_map) {
  323                         mb_map_full = TRUE;
  324                         printf("Out of mbuf clusters - adjust NMBCLUSTERS or increase maxusers!\n");
  325                         return (0);
  326                 }
  327                 if ((flags & M_NOWAIT) == 0)
  328                         panic("kmem_malloc(%ld): kmem_map too small: %ld total allocated",
  329                                 (long)size, (long)map->size);
  330                 return (0);
  331         }
  332         offset = addr - VM_MIN_KERNEL_ADDRESS;
  333         vm_object_reference(kmem_object);
  334         vm_map_insert(map, kmem_object, offset, addr, addr + size,
  335                 VM_PROT_ALL, VM_PROT_ALL, 0);
  336 
  337         for (i = 0; i < size; i += PAGE_SIZE) {
  338                 /*
  339                  * Note: if M_NOWAIT specified alone, allocate from 
  340                  * interrupt-safe queues only (just the free list).  If 
  341                  * M_ASLEEP or M_USE_RESERVE is also specified, we can also
  342                  * allocate from the cache.  Neither of the latter two
  343                  * flags may be specified from an interrupt since interrupts
  344                  * are not allowed to mess with the cache queue.
  345                  */
  346 retry:
  347                 m = vm_page_alloc(kmem_object, OFF_TO_IDX(offset + i),
  348                     ((flags & (M_NOWAIT|M_ASLEEP|M_USE_RESERVE)) == M_NOWAIT) ?
  349                         VM_ALLOC_INTERRUPT : 
  350                         VM_ALLOC_SYSTEM);
  351 
  352                 /*
  353                  * Ran out of space, free everything up and return. Don't need
  354                  * to lock page queues here as we know that the pages we got
  355                  * aren't on any queues.
  356                  */
  357                 if (m == NULL) {
  358                         if ((flags & M_NOWAIT) == 0) {
  359                                 vm_map_unlock(map);
  360                                 VM_WAIT;
  361                                 vm_map_lock(map);
  362                                 goto retry;
  363                         }
  364                         /* 
  365                          * Free the pages before removing the map entry.
  366                          * They are already marked busy.  Calling
  367                          * vm_map_delete before the pages has been freed or
  368                          * unbusied will cause a deadlock.
  369                          */
  370                         while (i != 0) {
  371                                 i -= PAGE_SIZE;
  372                                 m = vm_page_lookup(kmem_object,
  373                                                    OFF_TO_IDX(offset + i));
  374                                 vm_page_free(m);
  375                         }
  376                         vm_map_delete(map, addr, addr + size);
  377                         vm_map_unlock(map);
  378                         if (flags & M_ASLEEP) {
  379                                 VM_AWAIT;
  380                         }
  381                         return (0);
  382                 }
  383                 vm_page_flag_clear(m, PG_ZERO);
  384                 m->valid = VM_PAGE_BITS_ALL;
  385         }
  386 
  387         /*
  388          * Mark map entry as non-pageable. Assert: vm_map_insert() will never
  389          * be able to extend the previous entry so there will be a new entry
  390          * exactly corresponding to this address range and it will have
  391          * wired_count == 0.
  392          */
  393         if (!vm_map_lookup_entry(map, addr, &entry) ||
  394             entry->start != addr || entry->end != addr + size ||
  395             entry->wired_count != 0)
  396                 panic("kmem_malloc: entry not found or misaligned");
  397         entry->wired_count = 1;
  398 
  399         vm_map_simplify_entry(map, entry);
  400 
  401         /*
  402          * Loop thru pages, entering them in the pmap. (We cannot add them to
  403          * the wired count without wrapping the vm_page_queue_lock in
  404          * splimp...)
  405          */
  406         for (i = 0; i < size; i += PAGE_SIZE) {
  407                 m = vm_page_lookup(kmem_object, OFF_TO_IDX(offset + i));
  408                 vm_page_wire(m);
  409                 vm_page_wakeup(m);
  410                 /*
  411                  * Because this is kernel_pmap, this call will not block.
  412                  */
  413                 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL, 1);
  414                 vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE | PG_REFERENCED);
  415         }
  416         vm_map_unlock(map);
  417 
  418         return (addr);
  419 }
  420 
  421 /*
  422  *      kmem_alloc_wait:
  423  *
  424  *      Allocates pageable memory from a sub-map of the kernel.  If the submap
  425  *      has no room, the caller sleeps waiting for more memory in the submap.
  426  *
  427  *      This routine may block.
  428  */
  429 
  430 vm_offset_t
  431 kmem_alloc_wait(map, size)
  432         vm_map_t map;
  433         vm_size_t size;
  434 {
  435         vm_offset_t addr;
  436 
  437         size = round_page(size);
  438 
  439         for (;;) {
  440                 /*
  441                  * To make this work for more than one map, use the map's lock
  442                  * to lock out sleepers/wakers.
  443                  */
  444                 vm_map_lock(map);
  445                 if (vm_map_findspace(map, vm_map_min(map), size, &addr) == 0)
  446                         break;
  447                 /* no space now; see if we can ever get space */
  448                 if (vm_map_max(map) - vm_map_min(map) < size) {
  449                         vm_map_unlock(map);
  450                         return (0);
  451                 }
  452                 vm_map_unlock(map);
  453                 tsleep(map, PVM, "kmaw", 0);
  454         }
  455         vm_map_insert(map, NULL, (vm_offset_t) 0, addr, addr + size, VM_PROT_ALL, VM_PROT_ALL, 0);
  456         vm_map_unlock(map);
  457         return (addr);
  458 }
  459 
  460 /*
  461  *      kmem_free_wakeup:
  462  *
  463  *      Returns memory to a submap of the kernel, and wakes up any processes
  464  *      waiting for memory in that map.
  465  */
  466 void
  467 kmem_free_wakeup(map, addr, size)
  468         vm_map_t map;
  469         vm_offset_t addr;
  470         vm_size_t size;
  471 {
  472         vm_map_lock(map);
  473         (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size));
  474         wakeup(map);
  475         vm_map_unlock(map);
  476 }
  477 
  478 /*
  479  *      kmem_init:
  480  *
  481  *      Create the kernel map; insert a mapping covering kernel text, 
  482  *      data, bss, and all space allocated thus far (`boostrap' data).  The 
  483  *      new map will thus map the range between VM_MIN_KERNEL_ADDRESS and 
  484  *      `start' as allocated, and the range between `start' and `end' as free.
  485  */
  486 
  487 void
  488 kmem_init(start, end)
  489         vm_offset_t start, end;
  490 {
  491         register vm_map_t m;
  492 
  493         m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end);
  494         vm_map_lock(m);
  495         /* N.B.: cannot use kgdb to debug, starting with this assignment ... */
  496         kernel_map = m;
  497         kernel_map->system_map = 1;
  498         (void) vm_map_insert(m, NULL, (vm_offset_t) 0,
  499             VM_MIN_KERNEL_ADDRESS, start, VM_PROT_ALL, VM_PROT_ALL, 0);
  500         /* ... and ending with the completion of the above `insert' */
  501         vm_map_unlock(m);
  502 }
  503 

Cache object: 6eea28237ccfa8a318a2cead34b56ee8


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.