b5b40fa62b
1) Remove potential race conditions on waking up in vm_page_free_wakeup by making sure that it is at splvm(). 2) Fix another bug in vm_map_simplify_entry. 3) Be more complete about converting from default to swap pager when an object grows to be large enough that there can be a problem with data structure allocation under low memory conditions. 4) Make some madvise code more efficient. 5) Added some comments.
169 lines
4.6 KiB
C
169 lines
4.6 KiB
C
/*
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* Copyright (c) 1995, David Greenman
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by David Greenman.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: default_pager.c,v 1.8 1996/05/29 05:12:23 dyson Exp $
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/queue.h>
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#include <sys/vmmeter.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/vm_prot.h>
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#include <vm/vm_object.h>
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#include <vm/vm_page.h>
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#include <vm/vm_pager.h>
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#include <vm/default_pager.h>
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#include <vm/swap_pager.h>
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static vm_object_t default_pager_alloc __P((void *, vm_size_t, vm_prot_t,
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vm_ooffset_t));
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static void default_pager_dealloc __P((vm_object_t));
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static int default_pager_getpages __P((vm_object_t, vm_page_t *, int, int));
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static int default_pager_putpages __P((vm_object_t, vm_page_t *, int,
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boolean_t, int *));
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static boolean_t default_pager_haspage __P((vm_object_t, vm_pindex_t, int *,
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int *));
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/*
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* pagerops for OBJT_DEFAULT - "default pager".
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*/
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struct pagerops defaultpagerops = {
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NULL,
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default_pager_alloc,
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default_pager_dealloc,
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default_pager_getpages,
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default_pager_putpages,
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default_pager_haspage,
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NULL
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};
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/*
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* no_pager_alloc just returns an initialized object.
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*/
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static vm_object_t
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default_pager_alloc(handle, size, prot, offset)
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void *handle;
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register vm_size_t size;
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vm_prot_t prot;
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vm_ooffset_t offset;
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{
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if (handle != NULL)
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panic("default_pager_alloc: handle specified");
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return vm_object_allocate(OBJT_DEFAULT, OFF_TO_IDX(offset) + size);
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}
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static void
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default_pager_dealloc(object)
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vm_object_t object;
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{
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/*
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* OBJT_DEFAULT objects have no special resources allocated to them.
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*/
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}
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/*
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* The default pager has no backing store, so we always return
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* failure.
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*/
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static int
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default_pager_getpages(object, m, count, reqpage)
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vm_object_t object;
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vm_page_t *m;
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int count;
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int reqpage;
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{
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return VM_PAGER_FAIL;
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}
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static int
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default_pager_putpages(object, m, c, sync, rtvals)
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vm_object_t object;
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vm_page_t *m;
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int c;
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boolean_t sync;
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int *rtvals;
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{
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int i;
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/*
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* Try to convert the object type into a OBJT_SWAP.
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* If the swp structure allocation fails, convert it
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* back to OBJT_DEFAULT and return failure. Otherwise
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* pass this putpages to the swap pager.
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*/
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object->type = OBJT_SWAP;
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if (swap_pager_swp_alloc(object, M_KERNEL) != 0) {
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object->type = OBJT_DEFAULT;
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for (i = 0; i < c; i++)
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rtvals[i] = VM_PAGER_FAIL;
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return VM_PAGER_FAIL;
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}
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return swap_pager_putpages(object, m, c, sync, rtvals);
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}
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static boolean_t
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default_pager_haspage(object, pindex, before, after)
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vm_object_t object;
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vm_pindex_t pindex;
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int *before;
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int *after;
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{
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return FALSE;
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}
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void
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default_pager_convert_to_swap(object)
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vm_object_t object;
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{
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object->type = OBJT_SWAP;
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if (swap_pager_swp_alloc(object, M_KERNEL) != 0) {
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object->type = OBJT_DEFAULT;
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}
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}
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void
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default_pager_convert_to_swapq(object)
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vm_object_t object;
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{
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if (object &&
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(object->type == OBJT_DEFAULT) &&
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(object != kernel_object && object != kmem_object) &&
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(object->size > ((cnt.v_page_count - cnt.v_wire_count) / 4)))
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default_pager_convert_to_swap(object);
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}
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