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freebsd-skq/sys/vm/swap_pager.c
David Greenman 7fb0c17ed2 Deprecated remaining use of vm_deallocate. Deprecated vm_allocate_with_ 
pager(). Almost completely rewrote vm_mmap(); when John gets done with
the bottom half, it will be a complete rewrite. Deprecated most use of
vm_object_setpager(). Removed side effect of setting object persist
in vm_object_enter and moved this into the pager(s). A few other
cosmetic changes.
1995-02-21 01:22:48 +00:00

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/*
* 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 1.25 1995/02/02 09:08:00 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/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>
#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;
extern int vm_pageout_rate_limit;
static int cleandone;
extern int hz;
int swap_pager_full;
extern vm_map_t pager_map;
extern int vm_swap_size;
int no_swap_space = 1;
struct rlist *swaplist;
int nswaplist;
extern int vm_pio_needed;
#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];
extern vm_map_t kernel_map;
/* spc_flags values */
#define SPC_ERROR 0x01
#define SWB_EMPTY (-1)
struct swpclean swap_pager_done; /* list of compileted 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 rlist *swapfrag;
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 pendingiowait;
int require_swap_init;
void swap_pager_finish();
int dmmin, dmmax;
extern int vm_page_count;
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)
caddr_t 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(size);
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\n");
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]);
}
int swapwritecount = 0;
/*
* 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
wakeup((caddr_t) &vm_pages_needed);
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
wakeup((caddr_t) &vm_pages_needed);
}
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;
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)
wakeup((caddr_t) &vm_pages_needed);
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 (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
wakeup((caddr_t) &vm_pages_needed);
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
wakeup((caddr_t) &vm_pages_needed);
}
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;
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)
wakeup((caddr_t) &vm_pages_needed);
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)
wakeup((caddr_t) &vm_pages_needed);
swap_pager_needflags &= ~(SWAP_FREE_NEEDED|SWAP_FREE_NEEDED_BY_PAGEOUT);
++cleandone;
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;
if ((object->paging_in_progress -= spc->spc_count) == 0)
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",
(bp->b_flags & B_READ) ? "pagein" : "pageout",
bp->b_error, (u_long) bp->b_blkno, bp->b_bcount);
}
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;
wakeup((caddr_t) &vm_pages_needed);
}
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)) {
wakeup((caddr_t) &vm_pages_needed);
}
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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