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5f55e84104
freebsd/sys/vm/swap_pager.c
David Greenman 5f55e84104 Accessing pages beyond the end of a mapped file results in internal 
inconsistencies in the VM system that eventually lead to a panic. These
changes fix the behavior to conform to the behavior in SunOS, which is
to deny faults to pages beyond the EOF (returning SIGBUS). Internally,
this is implemented by requiring faults to be within the object size
boundaries. These changes exposed another bug, namely that passing in
an offset to mmap when trying to map an unnamed anonymous region also
results in internal inconsistencies. In this case, the offset is forced
to zero.

Reviewed by:	John Dyson and others
1995-05-18 02:59:26 +00:00

1710 lines
40 KiB
C
Raw Blame History

/*
* Copyright (c) 1994 John S. Dyson
* Copyright (c) 1990 University of Utah.
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Systems Programming Group of the University of Utah Computer
* Science Department.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: Utah $Hdr: swap_pager.c 1.4 91/04/30$
*
* @(#)swap_pager.c 8.9 (Berkeley) 3/21/94
* $Id: swap_pager.c,v 1.39 1995/05/14 03:00:08 davidg Exp $
*/
/*
* Quick hack to page to dedicated partition(s).
* TODO:
* Add multiprocessor locks
* Deal with async writes in a better fashion
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <miscfs/specfs/specdev.h>
#include <sys/rlist.h>
#include <vm/vm.h>
#include <vm/vm_pager.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/swap_pager.h>
#include <vm/vm_kern.h>
#ifndef NPENDINGIO
#define NPENDINGIO 10
#endif
int swap_pager_input __P((sw_pager_t, vm_page_t *, int, int));
int swap_pager_output __P((sw_pager_t, vm_page_t *, int, int, int *));
int nswiodone;
int swap_pager_full;
extern int vm_swap_size;
int no_swap_space = 1;
struct rlist *swaplist;
int nswaplist;
#define MAX_PAGEOUT_CLUSTER 8
TAILQ_HEAD(swpclean, swpagerclean);
typedef struct swpagerclean *swp_clean_t;
struct swpagerclean {
TAILQ_ENTRY(swpagerclean) spc_list;
int spc_flags;
struct buf *spc_bp;
sw_pager_t spc_swp;
vm_offset_t spc_kva;
int spc_count;
vm_page_t spc_m[MAX_PAGEOUT_CLUSTER];
} swcleanlist[NPENDINGIO];
/* spc_flags values */
#define SPC_ERROR 0x01
#define SWB_EMPTY (-1)
struct swpclean swap_pager_done; /* list of completed page cleans */
struct swpclean swap_pager_inuse; /* list of pending page cleans */
struct swpclean swap_pager_free; /* list of free pager clean structs */
struct pagerlst swap_pager_list; /* list of "named" anon regions */
struct pagerlst swap_pager_un_list; /* list of "unnamed" anon pagers */
#define SWAP_FREE_NEEDED 0x1 /* need a swap block */
#define SWAP_FREE_NEEDED_BY_PAGEOUT 0x2
int swap_pager_needflags;
struct pagerlst *swp_qs[] = {
&swap_pager_list, &swap_pager_un_list, (struct pagerlst *) 0
};
int swap_pager_putmulti();
struct pagerops swappagerops = {
swap_pager_init,
swap_pager_alloc,
swap_pager_dealloc,
swap_pager_getpage,
swap_pager_getmulti,
swap_pager_putpage,
swap_pager_putmulti,
swap_pager_haspage
};
int npendingio = NPENDINGIO;
int require_swap_init;
void swap_pager_finish();
int dmmin, dmmax;
static inline void
swapsizecheck()
{
if (vm_swap_size < 128 * btodb(PAGE_SIZE)) {
if (swap_pager_full == 0)
printf("swap_pager: out of space\n");
swap_pager_full = 1;
} else if (vm_swap_size > 192 * btodb(PAGE_SIZE))
swap_pager_full = 0;
}
void
swap_pager_init()
{
dfltpagerops = &swappagerops;
TAILQ_INIT(&swap_pager_list);
TAILQ_INIT(&swap_pager_un_list);
/*
* Initialize clean lists
*/
TAILQ_INIT(&swap_pager_inuse);
TAILQ_INIT(&swap_pager_done);
TAILQ_INIT(&swap_pager_free);
require_swap_init = 1;
/*
* Calculate the swap allocation constants.
*/
dmmin = CLBYTES / DEV_BSIZE;
dmmax = btodb(SWB_NPAGES * PAGE_SIZE) * 2;
}
/*
* Allocate a pager structure and associated resources.
* Note that if we are called from the pageout daemon (handle == NULL)
* we should not wait for memory as it could resulting in deadlock.
*/
vm_pager_t
swap_pager_alloc(handle, size, prot, offset)
void *handle;
register vm_size_t size;
vm_prot_t prot;
vm_offset_t offset;
{
register vm_pager_t pager;
register sw_pager_t swp;
int waitok;
int i, j;
if (require_swap_init) {
swp_clean_t spc;
struct buf *bp;
/*
* kva's are allocated here so that we dont need to keep doing
* kmem_alloc pageables at runtime
*/
for (i = 0, spc = swcleanlist; i < npendingio; i++, spc++) {
spc->spc_kva = kmem_alloc_pageable(pager_map, PAGE_SIZE * MAX_PAGEOUT_CLUSTER);
if (!spc->spc_kva) {
break;
}
spc->spc_bp = malloc(sizeof(*bp), M_TEMP, M_KERNEL);
if (!spc->spc_bp) {
kmem_free_wakeup(pager_map, spc->spc_kva, PAGE_SIZE);
break;
}
spc->spc_flags = 0;
TAILQ_INSERT_TAIL(&swap_pager_free, spc, spc_list);
}
require_swap_init = 0;
if (size == 0)
return (NULL);
}
/*
* If this is a "named" anonymous region, look it up and return the
* appropriate pager if it exists.
*/
if (handle) {
pager = vm_pager_lookup(&swap_pager_list, handle);
if (pager != NULL) {
/*
* Use vm_object_lookup to gain a reference to the
* object and also to remove from the object cache.
*/
if (vm_object_lookup(pager) == NULL)
panic("swap_pager_alloc: bad object");
return (pager);
}
}
/*
* Pager doesn't exist, allocate swap management resources and
* initialize.
*/
waitok = handle ? M_WAITOK : M_KERNEL;
pager = (vm_pager_t) malloc(sizeof *pager, M_VMPAGER, waitok);
if (pager == NULL)
return (NULL);
swp = (sw_pager_t) malloc(sizeof *swp, M_VMPGDATA, waitok);
if (swp == NULL) {
free((caddr_t) pager, M_VMPAGER);
return (NULL);
}
size = round_page(size);
swp->sw_osize = size;
swp->sw_nblocks = (btodb(size) + btodb(SWB_NPAGES * PAGE_SIZE) - 1) / btodb(SWB_NPAGES * PAGE_SIZE);
swp->sw_blocks = (sw_blk_t)
malloc(swp->sw_nblocks * sizeof(*swp->sw_blocks),
M_VMPGDATA, waitok);
if (swp->sw_blocks == NULL) {
free((caddr_t) swp, M_VMPGDATA);
free((caddr_t) pager, M_VMPAGER);
return (NULL);
}
for (i = 0; i < swp->sw_nblocks; i++) {
swp->sw_blocks[i].swb_valid = 0;
swp->sw_blocks[i].swb_locked = 0;
for (j = 0; j < SWB_NPAGES; j++)
swp->sw_blocks[i].swb_block[j] = SWB_EMPTY;
}
swp->sw_poip = 0;
swp->sw_allocsize = 0;
if (handle) {
vm_object_t object;
swp->sw_flags = SW_NAMED;
TAILQ_INSERT_TAIL(&swap_pager_list, pager, pg_list);
/*
* Consistant with other pagers: return with object
* referenced. Can't do this with handle == NULL since it
* might be the pageout daemon calling.
*/
object = vm_object_allocate(offset + size);
object->flags &= ~OBJ_INTERNAL;
vm_object_enter(object, pager);
object->pager = pager;
} else {
swp->sw_flags = 0;
TAILQ_INSERT_TAIL(&swap_pager_un_list, pager, pg_list);
}
pager->pg_handle = handle;
pager->pg_ops = &swappagerops;
pager->pg_type = PG_SWAP;
pager->pg_data = (caddr_t) swp;
return (pager);
}
/*
* returns disk block associated with pager and offset
* additionally, as a side effect returns a flag indicating
* if the block has been written
*/
inline static int *
swap_pager_diskaddr(swp, offset, valid)
sw_pager_t swp;
vm_offset_t offset;
int *valid;
{
register sw_blk_t swb;
int ix;
if (valid)
*valid = 0;
ix = offset / (SWB_NPAGES * PAGE_SIZE);
if ((swp->sw_blocks == NULL) || (ix >= swp->sw_nblocks) ||
(offset >= swp->sw_osize)) {
return (FALSE);
}
swb = &swp->sw_blocks[ix];
ix = (offset % (SWB_NPAGES * PAGE_SIZE)) / PAGE_SIZE;
if (valid)
*valid = swb->swb_valid & (1 << ix);
return &swb->swb_block[ix];
}
/*
* Utility routine to set the valid (written) bit for
* a block associated with a pager and offset
*/
static void
swap_pager_setvalid(swp, offset, valid)
sw_pager_t swp;
vm_offset_t offset;
int valid;
{
register sw_blk_t swb;
int ix;
ix = offset / (SWB_NPAGES * PAGE_SIZE);
if (swp->sw_blocks == NULL || ix >= swp->sw_nblocks)
return;
swb = &swp->sw_blocks[ix];
ix = (offset % (SWB_NPAGES * PAGE_SIZE)) / PAGE_SIZE;
if (valid)
swb->swb_valid |= (1 << ix);
else
swb->swb_valid &= ~(1 << ix);
return;
}
/*
* this routine allocates swap space with a fragmentation
* minimization policy.
*/
int
swap_pager_getswapspace(sw_pager_t swp, unsigned amount, unsigned *rtval)
{
vm_swap_size -= amount;
if (!rlist_alloc(&swaplist, amount, rtval)) {
vm_swap_size += amount;
return 0;
} else {
swapsizecheck();
swp->sw_allocsize += amount;
return 1;
}
}
/*
* this routine frees swap space with a fragmentation
* minimization policy.
*/
void
swap_pager_freeswapspace(sw_pager_t swp, unsigned from, unsigned to)
{
rlist_free(&swaplist, from, to);
vm_swap_size += (to - from) + 1;
swp->sw_allocsize -= (to - from) + 1;
swapsizecheck();
}
/*
* this routine frees swap blocks from a specified pager
*/
void
_swap_pager_freespace(swp, start, size)
sw_pager_t swp;
vm_offset_t start;
vm_offset_t size;
{
vm_offset_t i;
int s;
s = splbio();
for (i = start; i < round_page(start + size); i += PAGE_SIZE) {
int valid;
int *addr = swap_pager_diskaddr(swp, i, &valid);
if (addr && *addr != SWB_EMPTY) {
swap_pager_freeswapspace(swp, *addr, *addr + btodb(PAGE_SIZE) - 1);
if (valid) {
swap_pager_setvalid(swp, i, 0);
}
*addr = SWB_EMPTY;
}
}
splx(s);
}
void
swap_pager_freespace(pager, start, size)
vm_pager_t pager;
vm_offset_t start;
vm_offset_t size;
{
_swap_pager_freespace((sw_pager_t) pager->pg_data, start, size);
}
static void
swap_pager_free_swap(swp)
sw_pager_t swp;
{
register int i, j;
register sw_blk_t bp;
int first_block=0, block_count=0;
int s;
/*
* Free left over swap blocks
*/
s = splbio();
for (i = 0, bp = swp->sw_blocks; i < swp->sw_nblocks; i++, bp++) {
for (j = 0; j < SWB_NPAGES; j++) {
if (bp->swb_block[j] != SWB_EMPTY) {
/*
* initially the length of the run is zero
*/
if( block_count == 0) {
first_block = bp->swb_block[j];
block_count = btodb(PAGE_SIZE);
bp->swb_block[j] = SWB_EMPTY;
/*
* if the new block can be included into the current run
*/
} else if( bp->swb_block[j] == first_block + block_count) {
block_count += btodb(PAGE_SIZE);
bp->swb_block[j] = SWB_EMPTY;
/*
* terminate the previous run, and start a new one
*/
} else {
swap_pager_freeswapspace(swp, first_block,
(unsigned) first_block + block_count - 1);
first_block = bp->swb_block[j];
block_count = btodb(PAGE_SIZE);
bp->swb_block[j] = SWB_EMPTY;
}
}
}
}
if( block_count) {
swap_pager_freeswapspace(swp, first_block,
(unsigned) first_block + block_count - 1);
}
splx(s);
}
/*
* swap_pager_reclaim frees up over-allocated space from all pagers
* this eliminates internal fragmentation due to allocation of space
* for segments that are never swapped to. It has been written so that
* it does not block until the rlist_free operation occurs; it keeps
* the queues consistant.
*/
/*
* Maximum number of blocks (pages) to reclaim per pass
*/
#define MAXRECLAIM 128
void
swap_pager_reclaim()
{
vm_pager_t p;
sw_pager_t swp;
int i, j, k;
int s;
int reclaimcount;
static struct {
int address;
sw_pager_t pager;
} reclaims[MAXRECLAIM];
static int in_reclaim;
/*
* allow only one process to be in the swap_pager_reclaim subroutine
*/
s = splbio();
if (in_reclaim) {
tsleep((caddr_t) &in_reclaim, PSWP, "swrclm", 0);
splx(s);
return;
}
in_reclaim = 1;
reclaimcount = 0;
/* for each pager queue */
for (k = 0; swp_qs[k]; k++) {
p = swp_qs[k]->tqh_first;
while (p && (reclaimcount < MAXRECLAIM)) {
/*
* see if any blocks associated with a pager has been
* allocated but not used (written)
*/
swp = (sw_pager_t) p->pg_data;
for (i = 0; i < swp->sw_nblocks; i++) {
sw_blk_t swb = &swp->sw_blocks[i];
if (swb->swb_locked)
continue;
for (j = 0; j < SWB_NPAGES; j++) {
if (swb->swb_block[j] != SWB_EMPTY &&
(swb->swb_valid & (1 << j)) == 0) {
reclaims[reclaimcount].address = swb->swb_block[j];
reclaims[reclaimcount++].pager = swp;
swb->swb_block[j] = SWB_EMPTY;
if (reclaimcount >= MAXRECLAIM)
goto rfinished;
}
}
}
p = p->pg_list.tqe_next;
}
}
rfinished:
/*
* free the blocks that have been added to the reclaim list
*/
for (i = 0; i < reclaimcount; i++) {
swap_pager_freeswapspace(reclaims[i].pager, reclaims[i].address, reclaims[i].address + btodb(PAGE_SIZE) - 1);
}
splx(s);
in_reclaim = 0;
wakeup((caddr_t) &in_reclaim);
}
/*
* swap_pager_copy copies blocks from one pager to another and
* destroys the source pager
*/
void
swap_pager_copy(srcpager, srcoffset, dstpager, dstoffset, offset)
vm_pager_t srcpager;
vm_offset_t srcoffset;
vm_pager_t dstpager;
vm_offset_t dstoffset;
vm_offset_t offset;
{
sw_pager_t srcswp, dstswp;
vm_offset_t i;
int origsize;
int s;
if (vm_swap_size)
no_swap_space = 0;
if (no_swap_space)
return;
srcswp = (sw_pager_t) srcpager->pg_data;
origsize = srcswp->sw_allocsize;
dstswp = (sw_pager_t) dstpager->pg_data;
/*
* remove the source pager from the swap_pager internal queue
*/
s = splbio();
if (srcswp->sw_flags & SW_NAMED) {
TAILQ_REMOVE(&swap_pager_list, srcpager, pg_list);
srcswp->sw_flags &= ~SW_NAMED;
} else {
TAILQ_REMOVE(&swap_pager_un_list, srcpager, pg_list);
}
while (srcswp->sw_poip) {
tsleep((caddr_t) srcswp, PVM, "spgout", 0);
}
splx(s);
/*
* clean all of the pages that are currently active and finished
*/
(void) swap_pager_clean();
s = splbio();
/*
* transfer source to destination
*/
for (i = 0; i < dstswp->sw_osize; i += PAGE_SIZE) {
int srcvalid, dstvalid;
int *srcaddrp = swap_pager_diskaddr(srcswp, i + offset + srcoffset,
&srcvalid);
int *dstaddrp;
/*
* see if the source has space allocated
*/
if (srcaddrp && *srcaddrp != SWB_EMPTY) {
/*
* if the source is valid and the dest has no space,
* then copy the allocation from the srouce to the
* dest.
*/
if (srcvalid) {
dstaddrp = swap_pager_diskaddr(dstswp, i + dstoffset,
&dstvalid);
/*
* if the dest already has a valid block,
* deallocate the source block without
* copying.
*/
if (!dstvalid && dstaddrp && *dstaddrp != SWB_EMPTY) {
swap_pager_freeswapspace(dstswp, *dstaddrp,
*dstaddrp + btodb(PAGE_SIZE) - 1);
*dstaddrp = SWB_EMPTY;
}
if (dstaddrp && *dstaddrp == SWB_EMPTY) {
*dstaddrp = *srcaddrp;
*srcaddrp = SWB_EMPTY;
dstswp->sw_allocsize += btodb(PAGE_SIZE);
srcswp->sw_allocsize -= btodb(PAGE_SIZE);
swap_pager_setvalid(dstswp, i + dstoffset, 1);
}
}
/*
* if the source is not empty at this point, then
* deallocate the space.
*/
if (*srcaddrp != SWB_EMPTY) {
swap_pager_freeswapspace(srcswp, *srcaddrp,
*srcaddrp + btodb(PAGE_SIZE) - 1);
*srcaddrp = SWB_EMPTY;
}
}
}
splx(s);
/*
* Free left over swap blocks
*/
swap_pager_free_swap(srcswp);
if( srcswp->sw_allocsize)
printf("swap_pager_copy: *warning* pager with %d blocks (orig: %d)\n", srcswp->sw_allocsize, origsize);
free((caddr_t) srcswp->sw_blocks, M_VMPGDATA);
srcswp->sw_blocks = 0;
free((caddr_t) srcswp, M_VMPGDATA);
srcpager->pg_data = 0;
free((caddr_t) srcpager, M_VMPAGER);
return;
}
void
swap_pager_dealloc(pager)
vm_pager_t pager;
{
register sw_pager_t swp;
int s;
/*
* Remove from list right away so lookups will fail if we block for
* pageout completion.
*/
s = splbio();
swp = (sw_pager_t) pager->pg_data;
if (swp->sw_flags & SW_NAMED) {
TAILQ_REMOVE(&swap_pager_list, pager, pg_list);
swp->sw_flags &= ~SW_NAMED;
} else {
TAILQ_REMOVE(&swap_pager_un_list, pager, pg_list);
}
/*
* Wait for all pageouts to finish and remove all entries from
* cleaning list.
*/
while (swp->sw_poip) {
tsleep((caddr_t) swp, PVM, "swpout", 0);
}
splx(s);
(void) swap_pager_clean();
/*
* Free left over swap blocks
*/
swap_pager_free_swap(swp);
if( swp->sw_allocsize)
printf("swap_pager_dealloc: *warning* freeing pager with %d blocks\n", swp->sw_allocsize);
/*
* Free swap management resources
*/
free((caddr_t) swp->sw_blocks, M_VMPGDATA);
swp->sw_blocks = 0;
free((caddr_t) swp, M_VMPGDATA);
pager->pg_data = 0;
free((caddr_t) pager, M_VMPAGER);
}
/*
* swap_pager_getmulti can get multiple pages.
*/
int
swap_pager_getmulti(pager, m, count, reqpage, sync)
vm_pager_t pager;
vm_page_t *m;
int count;
int reqpage;
boolean_t sync;
{
if (reqpage >= count)
panic("swap_pager_getmulti: reqpage >= count");
return swap_pager_input((sw_pager_t) pager->pg_data, m, count, reqpage);
}
/*
* swap_pager_getpage gets individual pages
*/
int
swap_pager_getpage(pager, m, sync)
vm_pager_t pager;
vm_page_t m;
boolean_t sync;
{
vm_page_t marray[1];
marray[0] = m;
return swap_pager_input((sw_pager_t) pager->pg_data, marray, 1, 0);
}
int
swap_pager_putmulti(pager, m, c, sync, rtvals)
vm_pager_t pager;
vm_page_t *m;
int c;
boolean_t sync;
int *rtvals;
{
int flags;
if (pager == NULL) {
(void) swap_pager_clean();
return VM_PAGER_OK;
}
flags = B_WRITE;
if (!sync)
flags |= B_ASYNC;
return swap_pager_output((sw_pager_t) pager->pg_data, m, c, flags, rtvals);
}
/*
* swap_pager_putpage writes individual pages
*/
int
swap_pager_putpage(pager, m, sync)
vm_pager_t pager;
vm_page_t m;
boolean_t sync;
{
int flags;
vm_page_t marray[1];
int rtvals[1];
if (pager == NULL) {
(void) swap_pager_clean();
return VM_PAGER_OK;
}
marray[0] = m;
flags = B_WRITE;
if (!sync)
flags |= B_ASYNC;
swap_pager_output((sw_pager_t) pager->pg_data, marray, 1, flags, rtvals);
return rtvals[0];
}
static inline int
const
swap_pager_block_index(swp, offset)
sw_pager_t swp;
vm_offset_t offset;
{
return (offset / (SWB_NPAGES * PAGE_SIZE));
}
static inline int
const
swap_pager_block_offset(swp, offset)
sw_pager_t swp;
vm_offset_t offset;
{
return ((offset % (PAGE_SIZE * SWB_NPAGES)) / PAGE_SIZE);
}
/*
* _swap_pager_haspage returns TRUE if the pager has data that has
* been written out.
*/
static boolean_t
_swap_pager_haspage(swp, offset)
sw_pager_t swp;
vm_offset_t offset;
{
register sw_blk_t swb;
int ix;
ix = offset / (SWB_NPAGES * PAGE_SIZE);
if (swp->sw_blocks == NULL || ix >= swp->sw_nblocks) {
return (FALSE);
}
swb = &swp->sw_blocks[ix];
ix = (offset % (SWB_NPAGES * PAGE_SIZE)) / PAGE_SIZE;
if (swb->swb_block[ix] != SWB_EMPTY) {
if (swb->swb_valid & (1 << ix))
return TRUE;
}
return (FALSE);
}
/*
* swap_pager_haspage is the externally accessible version of
* _swap_pager_haspage above. this routine takes a vm_pager_t
* for an argument instead of sw_pager_t.
*/
boolean_t
swap_pager_haspage(pager, offset)
vm_pager_t pager;
vm_offset_t offset;
{
return _swap_pager_haspage((sw_pager_t) pager->pg_data, offset);
}
/*
* swap_pager_freepage is a convienience routine that clears the busy
* bit and deallocates a page.
*/
static void
swap_pager_freepage(m)
vm_page_t m;
{
PAGE_WAKEUP(m);
vm_page_free(m);
}
/*
* swap_pager_ridpages is a convienience routine that deallocates all
* but the required page. this is usually used in error returns that
* need to invalidate the "extra" readahead pages.
*/
static void
swap_pager_ridpages(m, count, reqpage)
vm_page_t *m;
int count;
int reqpage;
{
int i;
for (i = 0; i < count; i++)
if (i != reqpage)
swap_pager_freepage(m[i]);
}
/*
* swap_pager_iodone1 is the completion routine for both reads and async writes
*/
void
swap_pager_iodone1(bp)
struct buf *bp;
{
bp->b_flags |= B_DONE;
bp->b_flags &= ~B_ASYNC;
wakeup((caddr_t) bp);
}
int
swap_pager_input(swp, m, count, reqpage)
register sw_pager_t swp;
vm_page_t *m;
int count, reqpage;
{
register struct buf *bp;
sw_blk_t swb[count];
register int s;
int i;
boolean_t rv;
vm_offset_t kva, off[count];
swp_clean_t spc;
vm_offset_t paging_offset;
vm_object_t object;
int reqaddr[count];
int sequential;
int first, last;
int failed;
int reqdskregion;
object = m[reqpage]->object;
paging_offset = object->paging_offset;
sequential = (m[reqpage]->offset == (object->last_read + PAGE_SIZE));
/*
* First determine if the page exists in the pager if this is a sync
* read. This quickly handles cases where we are following shadow
* chains looking for the top level object with the page.
*/
if (swp->sw_blocks == NULL) {
swap_pager_ridpages(m, count, reqpage);
return (VM_PAGER_FAIL);
}
for (i = 0; i < count; i++) {
vm_offset_t foff = m[i]->offset + paging_offset;
int ix = swap_pager_block_index(swp, foff);
if (ix >= swp->sw_nblocks) {
int j;
if (i <= reqpage) {
swap_pager_ridpages(m, count, reqpage);
return (VM_PAGER_FAIL);
}
for (j = i; j < count; j++) {
swap_pager_freepage(m[j]);
}
count = i;
break;
}
swb[i] = &swp->sw_blocks[ix];
off[i] = swap_pager_block_offset(swp, foff);
reqaddr[i] = swb[i]->swb_block[off[i]];
}
/* make sure that our required input request is existant */
if (reqaddr[reqpage] == SWB_EMPTY ||
(swb[reqpage]->swb_valid & (1 << off[reqpage])) == 0) {
swap_pager_ridpages(m, count, reqpage);
return (VM_PAGER_FAIL);
}
reqdskregion = reqaddr[reqpage] / dmmax;
/*
* search backwards for the first contiguous page to transfer
*/
failed = 0;
first = 0;
for (i = reqpage - 1; i >= 0; --i) {
if (sequential || failed || (reqaddr[i] == SWB_EMPTY) ||
(swb[i]->swb_valid & (1 << off[i])) == 0 ||
(reqaddr[i] != (reqaddr[reqpage] + (i - reqpage) * btodb(PAGE_SIZE))) ||
((reqaddr[i] / dmmax) != reqdskregion)) {
failed = 1;
swap_pager_freepage(m[i]);
if (first == 0)
first = i + 1;
}
}
/*
* search forwards for the last contiguous page to transfer
*/
failed = 0;
last = count;
for (i = reqpage + 1; i < count; i++) {
if (failed || (reqaddr[i] == SWB_EMPTY) ||
(swb[i]->swb_valid & (1 << off[i])) == 0 ||
(reqaddr[i] != (reqaddr[reqpage] + (i - reqpage) * btodb(PAGE_SIZE))) ||
((reqaddr[i] / dmmax) != reqdskregion)) {
failed = 1;
swap_pager_freepage(m[i]);
if (last == count)
last = i;
}
}
count = last;
if (first != 0) {
for (i = first; i < count; i++) {
m[i - first] = m[i];
reqaddr[i - first] = reqaddr[i];
off[i - first] = off[i];
}
count -= first;
reqpage -= first;
}
++swb[reqpage]->swb_locked;
/*
* at this point: "m" is a pointer to the array of vm_page_t for
* paging I/O "count" is the number of vm_page_t entries represented
* by "m" "object" is the vm_object_t for I/O "reqpage" is the index
* into "m" for the page actually faulted
*/
spc = NULL; /* we might not use an spc data structure */
if ((count == 1) && (swap_pager_free.tqh_first != NULL)) {
/*
* if a kva has not been allocated, we can only do a one page
* transfer, so we free the other pages that might have been
* allocated by vm_fault.
*/
swap_pager_ridpages(m, count, reqpage);
m[0] = m[reqpage];
reqaddr[0] = reqaddr[reqpage];
count = 1;
reqpage = 0;
/*
* get a swap pager clean data structure, block until we get
* it
*/
if (swap_pager_free.tqh_first == NULL) {
s = splbio();
if (curproc == pageproc)
(void) swap_pager_clean();
else
pagedaemon_wakeup();
while (swap_pager_free.tqh_first == NULL) {
swap_pager_needflags |= SWAP_FREE_NEEDED;
if (curproc == pageproc)
swap_pager_needflags |= SWAP_FREE_NEEDED_BY_PAGEOUT;
tsleep((caddr_t) &swap_pager_free,
PVM, "swpfre", 0);
if (curproc == pageproc)
(void) swap_pager_clean();
else
pagedaemon_wakeup();
}
splx(s);
}
spc = swap_pager_free.tqh_first;
TAILQ_REMOVE(&swap_pager_free, spc, spc_list);
kva = spc->spc_kva;
bp = spc->spc_bp;
bzero(bp, sizeof *bp);
bp->b_spc = spc;
bp->b_vnbufs.le_next = NOLIST;
} else {
/*
* Get a swap buffer header to perform the IO
*/
bp = getpbuf();
kva = (vm_offset_t) bp->b_data;
}
/*
* map our page(s) into kva for input
*/
pmap_qenter(kva, m, count);
bp->b_flags = B_BUSY | B_READ | B_CALL | B_PAGING;
bp->b_iodone = swap_pager_iodone1;
bp->b_proc = &proc0; /* XXX (but without B_PHYS set this is ok) */
bp->b_rcred = bp->b_wcred = bp->b_proc->p_ucred;
crhold(bp->b_rcred);
crhold(bp->b_wcred);
bp->b_un.b_addr = (caddr_t) kva;
bp->b_blkno = reqaddr[0];
bp->b_bcount = PAGE_SIZE * count;
bp->b_bufsize = PAGE_SIZE * count;
pbgetvp(swapdev_vp, bp);
swp->sw_piip++;
cnt.v_swapin++;
cnt.v_swappgsin += count;
/*
* perform the I/O
*/
VOP_STRATEGY(bp);
/*
* wait for the sync I/O to complete
*/
s = splbio();
while ((bp->b_flags & B_DONE) == 0) {
tsleep((caddr_t) bp, PVM, "swread", 0);
}
if (bp->b_flags & B_ERROR) {
printf("swap_pager: I/O error - pagein failed; blkno %d, size %d, error %d\n",
bp->b_blkno, bp->b_bcount, bp->b_error);
rv = VM_PAGER_ERROR;
} else {
rv = VM_PAGER_OK;
}
--swp->sw_piip;
if (swp->sw_piip == 0)
wakeup((caddr_t) swp);
/*
* relpbuf does this, but we maintain our own buffer list also...
*/
if (bp->b_vp)
pbrelvp(bp);
splx(s);
--swb[reqpage]->swb_locked;
/*
* remove the mapping for kernel virtual
*/
pmap_qremove(kva, count);
if (spc) {
m[reqpage]->object->last_read = m[reqpage]->offset;
if (bp->b_flags & B_WANTED)
wakeup((caddr_t) bp);
/*
* if we have used an spc, we need to free it.
*/
if (bp->b_rcred != NOCRED)
crfree(bp->b_rcred);
if (bp->b_wcred != NOCRED)
crfree(bp->b_wcred);
TAILQ_INSERT_TAIL(&swap_pager_free, spc, spc_list);
if (swap_pager_needflags & SWAP_FREE_NEEDED) {
wakeup((caddr_t) &swap_pager_free);
}
if( swap_pager_needflags & SWAP_FREE_NEEDED_BY_PAGEOUT)
pagedaemon_wakeup();
swap_pager_needflags &= ~(SWAP_FREE_NEEDED|SWAP_FREE_NEEDED_BY_PAGEOUT);
} else {
/*
* release the physical I/O buffer
*/
relpbuf(bp);
/*
* finish up input if everything is ok
*/
if (rv == VM_PAGER_OK) {
for (i = 0; i < count; i++) {
pmap_clear_modify(VM_PAGE_TO_PHYS(m[i]));
m[i]->dirty = 0;
if (i != reqpage) {
/*
* whether or not to leave the page
* activated is up in the air, but we
* should put the page on a page queue
* somewhere. (it already is in the
* object). After some emperical
* results, it is best to deactivate
* the readahead pages.
*/
vm_page_deactivate(m[i]);
/*
* just in case someone was asking for
* this page we now tell them that it
* is ok to use
*/
m[i]->valid = VM_PAGE_BITS_ALL;
PAGE_WAKEUP(m[i]);
}
}
m[reqpage]->object->last_read = m[count-1]->offset;
/*
* If we're out of swap space, then attempt to free
* some whenever pages are brought in. We must clear
* the clean flag so that the page contents will be
* preserved.
*/
if (swap_pager_full) {
for (i = 0; i < count; i++) {
m[i]->dirty = VM_PAGE_BITS_ALL;
}
_swap_pager_freespace(swp, m[0]->offset + paging_offset, count * PAGE_SIZE);
}
} else {
swap_pager_ridpages(m, count, reqpage);
}
}
return (rv);
}
int
swap_pager_output(swp, m, count, flags, rtvals)
register sw_pager_t swp;
vm_page_t *m;
int count;
int flags;
int *rtvals;
{
register struct buf *bp;
sw_blk_t swb[count];
register int s;
int i, j, ix;
boolean_t rv;
vm_offset_t kva, off, foff;
swp_clean_t spc;
vm_offset_t paging_offset;
vm_object_t object;
int reqaddr[count];
int failed;
if (vm_swap_size)
no_swap_space = 0;
if (no_swap_space) {
for (i = 0; i < count; i++)
rtvals[i] = VM_PAGER_FAIL;
return VM_PAGER_FAIL;
}
spc = NULL;
object = m[0]->object;
paging_offset = object->paging_offset;
failed = 0;
for (j = 0; j < count; j++) {
foff = m[j]->offset + paging_offset;
ix = swap_pager_block_index(swp, foff);
swb[j] = 0;
if (swp->sw_blocks == NULL || ix >= swp->sw_nblocks) {
rtvals[j] = VM_PAGER_FAIL;
failed = 1;
continue;
} else {
rtvals[j] = VM_PAGER_OK;
}
swb[j] = &swp->sw_blocks[ix];
++swb[j]->swb_locked;
if (failed) {
rtvals[j] = VM_PAGER_FAIL;
continue;
}
off = swap_pager_block_offset(swp, foff);
reqaddr[j] = swb[j]->swb_block[off];
if (reqaddr[j] == SWB_EMPTY) {
int blk;
int tries;
int ntoget;
tries = 0;
s = splbio();
/*
* if any other pages have been allocated in this
* block, we only try to get one page.
*/
for (i = 0; i < SWB_NPAGES; i++) {
if (swb[j]->swb_block[i] != SWB_EMPTY)
break;
}
ntoget = (i == SWB_NPAGES) ? SWB_NPAGES : 1;
/*
* this code is alittle conservative, but works (the
* intent of this code is to allocate small chunks for
* small objects)
*/
if ((foff == 0) &&
((ntoget * PAGE_SIZE) > object->size)) {
ntoget = (object->size + (PAGE_SIZE - 1)) / PAGE_SIZE;
}
retrygetspace:
if (!swap_pager_full && ntoget > 1 &&
swap_pager_getswapspace(swp, ntoget * btodb(PAGE_SIZE), &blk)) {
for (i = 0; i < ntoget; i++) {
swb[j]->swb_block[i] = blk + btodb(PAGE_SIZE) * i;
swb[j]->swb_valid = 0;
}
reqaddr[j] = swb[j]->swb_block[off];
} else if (!swap_pager_getswapspace(swp, btodb(PAGE_SIZE),
&swb[j]->swb_block[off])) {
/*
* if the allocation has failed, we try to
* reclaim space and retry.
*/
if (++tries == 1) {
swap_pager_reclaim();
goto retrygetspace;
}
rtvals[j] = VM_PAGER_AGAIN;
failed = 1;
swap_pager_full = 1;
} else {
reqaddr[j] = swb[j]->swb_block[off];
swb[j]->swb_valid &= ~(1 << off);
}
splx(s);
}
}
/*
* search forwards for the last contiguous page to transfer
*/
failed = 0;
for (i = 0; i < count; i++) {
if (failed || (reqaddr[i] != reqaddr[0] + i * btodb(PAGE_SIZE)) ||
(reqaddr[i] / dmmax) != (reqaddr[0] / dmmax) ||
(rtvals[i] != VM_PAGER_OK)) {
failed = 1;
if (rtvals[i] == VM_PAGER_OK)
rtvals[i] = VM_PAGER_AGAIN;
}
}
for (i = 0; i < count; i++) {
if (rtvals[i] != VM_PAGER_OK) {
if (swb[i])
--swb[i]->swb_locked;
}
}
for (i = 0; i < count; i++)
if (rtvals[i] != VM_PAGER_OK)
break;
if (i == 0) {
return VM_PAGER_AGAIN;
}
count = i;
for (i = 0; i < count; i++) {
if (reqaddr[i] == SWB_EMPTY)
printf("I/O to empty block????\n");
}
/*
* For synchronous writes, we clean up all completed async pageouts.
*/
if ((flags & B_ASYNC) == 0) {
swap_pager_clean();
}
kva = 0;
/*
* get a swap pager clean data structure, block until we get it
*/
if (swap_pager_free.tqh_first == NULL ||
swap_pager_free.tqh_first->spc_list.tqe_next == NULL ||
swap_pager_free.tqh_first->spc_list.tqe_next->spc_list.tqe_next == NULL) {
s = splbio();
if (curproc == pageproc) {
(void) swap_pager_clean();
#if 0
splx(s);
return VM_PAGER_AGAIN;
#endif
} else
pagedaemon_wakeup();
while (swap_pager_free.tqh_first == NULL ||
swap_pager_free.tqh_first->spc_list.tqe_next == NULL ||
swap_pager_free.tqh_first->spc_list.tqe_next->spc_list.tqe_next == NULL) {
if (curproc == pageproc) {
swap_pager_needflags |= SWAP_FREE_NEEDED_BY_PAGEOUT;
if((cnt.v_free_count + cnt.v_cache_count) > cnt.v_free_reserved)
wakeup((caddr_t) &cnt.v_free_count);
}
swap_pager_needflags |= SWAP_FREE_NEEDED;
tsleep((caddr_t) &swap_pager_free,
PVM, "swpfre", 0);
if (curproc == pageproc)
(void) swap_pager_clean();
else
pagedaemon_wakeup();
}
splx(s);
}
spc = swap_pager_free.tqh_first;
TAILQ_REMOVE(&swap_pager_free, spc, spc_list);
kva = spc->spc_kva;
/*
* map our page(s) into kva for I/O
*/
pmap_qenter(kva, m, count);
/*
* get the base I/O offset into the swap file
*/
for (i = 0; i < count; i++) {
foff = m[i]->offset + paging_offset;
off = swap_pager_block_offset(swp, foff);
/*
* set the valid bit
*/
swb[i]->swb_valid |= (1 << off);
/*
* and unlock the data structure
*/
--swb[i]->swb_locked;
}
/*
* Get a swap buffer header and perform the IO
*/
bp = spc->spc_bp;
bzero(bp, sizeof *bp);
bp->b_spc = spc;
bp->b_vnbufs.le_next = NOLIST;
bp->b_flags = B_BUSY | B_PAGING;
bp->b_proc = &proc0; /* XXX (but without B_PHYS set this is ok) */
bp->b_rcred = bp->b_wcred = bp->b_proc->p_ucred;
if (bp->b_rcred != NOCRED)
crhold(bp->b_rcred);
if (bp->b_wcred != NOCRED)
crhold(bp->b_wcred);
bp->b_data = (caddr_t) kva;
bp->b_blkno = reqaddr[0];
pbgetvp(swapdev_vp, bp);
bp->b_bcount = PAGE_SIZE * count;
bp->b_bufsize = PAGE_SIZE * count;
swapdev_vp->v_numoutput++;
/*
* If this is an async write we set up additional buffer fields and
* place a "cleaning" entry on the inuse queue.
*/
s = splbio();
if (flags & B_ASYNC) {
spc->spc_flags = 0;
spc->spc_swp = swp;
for (i = 0; i < count; i++)
spc->spc_m[i] = m[i];
spc->spc_count = count;
/*
* the completion routine for async writes
*/
bp->b_flags |= B_CALL;
bp->b_iodone = swap_pager_iodone;
bp->b_dirtyoff = 0;
bp->b_dirtyend = bp->b_bcount;
swp->sw_poip++;
TAILQ_INSERT_TAIL(&swap_pager_inuse, spc, spc_list);
} else {
swp->sw_poip++;
bp->b_flags |= B_CALL;
bp->b_iodone = swap_pager_iodone1;
}
cnt.v_swapout++;
cnt.v_swappgsout += count;
/*
* perform the I/O
*/
VOP_STRATEGY(bp);
if ((flags & (B_READ | B_ASYNC)) == B_ASYNC) {
if ((bp->b_flags & B_DONE) == B_DONE) {
swap_pager_clean();
}
splx(s);
for (i = 0; i < count; i++) {
rtvals[i] = VM_PAGER_PEND;
}
return VM_PAGER_PEND;
}
/*
* wait for the sync I/O to complete
*/
while ((bp->b_flags & B_DONE) == 0) {
tsleep((caddr_t) bp, PVM, "swwrt", 0);
}
if (bp->b_flags & B_ERROR) {
printf("swap_pager: I/O error - pageout failed; blkno %d, size %d, error %d\n",
bp->b_blkno, bp->b_bcount, bp->b_error);
rv = VM_PAGER_ERROR;
} else {
rv = VM_PAGER_OK;
}
--swp->sw_poip;
if (swp->sw_poip == 0)
wakeup((caddr_t) swp);
if (bp->b_vp)
pbrelvp(bp);
if (bp->b_flags & B_WANTED)
wakeup((caddr_t) bp);
splx(s);
/*
* remove the mapping for kernel virtual
*/
pmap_qremove(kva, count);
/*
* if we have written the page, then indicate that the page is clean.
*/
if (rv == VM_PAGER_OK) {
for (i = 0; i < count; i++) {
if (rtvals[i] == VM_PAGER_OK) {
pmap_clear_modify(VM_PAGE_TO_PHYS(m[i]));
m[i]->dirty = 0;
/*
* optimization, if a page has been read
* during the pageout process, we activate it.
*/
if ((m[i]->flags & PG_ACTIVE) == 0 &&
((m[i]->flags & (PG_WANTED|PG_REFERENCED)) ||
pmap_is_referenced(VM_PAGE_TO_PHYS(m[i])))) {
vm_page_activate(m[i]);
}
}
}
} else {
for (i = 0; i < count; i++) {
rtvals[i] = rv;
}
}
if (bp->b_rcred != NOCRED)
crfree(bp->b_rcred);
if (bp->b_wcred != NOCRED)
crfree(bp->b_wcred);
TAILQ_INSERT_TAIL(&swap_pager_free, spc, spc_list);
if (swap_pager_needflags & SWAP_FREE_NEEDED) {
wakeup((caddr_t) &swap_pager_free);
}
if( swap_pager_needflags & SWAP_FREE_NEEDED_BY_PAGEOUT)
pagedaemon_wakeup();
swap_pager_needflags &= ~(SWAP_FREE_NEEDED|SWAP_FREE_NEEDED_BY_PAGEOUT);
return (rv);
}
boolean_t
swap_pager_clean()
{
register swp_clean_t spc, tspc;
register int s;
tspc = NULL;
if (swap_pager_done.tqh_first == NULL)
return FALSE;
for (;;) {
s = splbio();
/*
* Look up and removal from done list must be done at splbio()
* to avoid conflicts with swap_pager_iodone.
*/
while ((spc = swap_pager_done.tqh_first) != 0) {
pmap_qremove(spc->spc_kva, spc->spc_count);
swap_pager_finish(spc);
TAILQ_REMOVE(&swap_pager_done, spc, spc_list);
goto doclean;
}
/*
* No operations done, thats all we can do for now.
*/
splx(s);
break;
/*
* The desired page was found to be busy earlier in the scan
* but has since completed.
*/
doclean:
if (tspc && tspc == spc) {
tspc = NULL;
}
spc->spc_flags = 0;
TAILQ_INSERT_TAIL(&swap_pager_free, spc, spc_list);
if (swap_pager_needflags & SWAP_FREE_NEEDED) {
wakeup((caddr_t) &swap_pager_free);
}
if( swap_pager_needflags & SWAP_FREE_NEEDED_BY_PAGEOUT)
pagedaemon_wakeup();
swap_pager_needflags &= ~(SWAP_FREE_NEEDED|SWAP_FREE_NEEDED_BY_PAGEOUT);
splx(s);
}
return (tspc ? TRUE : FALSE);
}
void
swap_pager_finish(spc)
register swp_clean_t spc;
{
vm_object_t object = spc->spc_m[0]->object;
int i;
object->paging_in_progress -= spc->spc_count;
if ((object->paging_in_progress == 0) &&
(object->flags & OBJ_PIPWNT)) {
object->flags &= ~OBJ_PIPWNT;
thread_wakeup((int) object);
}
/*
* If no error, mark as clean and inform the pmap system. If error,
* mark as dirty so we will try again. (XXX could get stuck doing
* this, should give up after awhile)
*/
if (spc->spc_flags & SPC_ERROR) {
for (i = 0; i < spc->spc_count; i++) {
printf("swap_pager_finish: I/O error, clean of page %lx failed\n",
(u_long) VM_PAGE_TO_PHYS(spc->spc_m[i]));
}
} else {
for (i = 0; i < spc->spc_count; i++) {
pmap_clear_modify(VM_PAGE_TO_PHYS(spc->spc_m[i]));
spc->spc_m[i]->dirty = 0;
if ((spc->spc_m[i]->flags & PG_ACTIVE) == 0 &&
((spc->spc_m[i]->flags & PG_WANTED) || pmap_is_referenced(VM_PAGE_TO_PHYS(spc->spc_m[i]))))
vm_page_activate(spc->spc_m[i]);
}
}
for (i = 0; i < spc->spc_count; i++) {
/*
* we wakeup any processes that are waiting on these pages.
*/
PAGE_WAKEUP(spc->spc_m[i]);
}
nswiodone -= spc->spc_count;
return;
}
/*
* swap_pager_iodone
*/
void
swap_pager_iodone(bp)
register struct buf *bp;
{
register swp_clean_t spc;
int s;
s = splbio();
spc = (swp_clean_t) bp->b_spc;
TAILQ_REMOVE(&swap_pager_inuse, spc, spc_list);
TAILQ_INSERT_TAIL(&swap_pager_done, spc, spc_list);
if (bp->b_flags & B_ERROR) {
spc->spc_flags |= SPC_ERROR;
printf("swap_pager: I/O error - async %s failed; blkno %lu, size %ld, error %d\n",
(bp->b_flags & B_READ) ? "pagein" : "pageout",
(u_long) bp->b_blkno, bp->b_bcount, bp->b_error);
}
if (bp->b_vp)
pbrelvp(bp);
if (bp->b_flags & B_WANTED)
wakeup((caddr_t) bp);
if (bp->b_rcred != NOCRED)
crfree(bp->b_rcred);
if (bp->b_wcred != NOCRED)
crfree(bp->b_wcred);
nswiodone += spc->spc_count;
if (--spc->spc_swp->sw_poip == 0) {
wakeup((caddr_t) spc->spc_swp);
}
if ((swap_pager_needflags & SWAP_FREE_NEEDED) ||
swap_pager_inuse.tqh_first == 0) {
swap_pager_needflags &= ~SWAP_FREE_NEEDED;
wakeup((caddr_t) &swap_pager_free);
}
if( swap_pager_needflags & SWAP_FREE_NEEDED_BY_PAGEOUT) {
swap_pager_needflags &= ~SWAP_FREE_NEEDED_BY_PAGEOUT;
pagedaemon_wakeup();
}
if (vm_pageout_pages_needed) {
wakeup((caddr_t) &vm_pageout_pages_needed);
vm_pageout_pages_needed = 0;
}
if ((swap_pager_inuse.tqh_first == NULL) ||
((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min &&
nswiodone + cnt.v_free_count + cnt.v_cache_count >= cnt.v_free_min)) {
pagedaemon_wakeup();
}
splx(s);
}
/*
* return true if any swap control structures can be allocated
*/
int
swap_pager_ready()
{
if (swap_pager_free.tqh_first)
return 1;
else
return 0;
}
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