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BSD 4_4 release
[unix-history] / usr / src / sys / vm / swap_pager.c
/*
* 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 8.1 (Berkeley) 6/11/93
*/
/*
* 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/map.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <miscfs/specfs/specdev.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/swap_pager.h>
#define NSWSIZES 16 /* size of swtab */
#define NPENDINGIO 64 /* max # of pending cleans */
#define MAXDADDRS 64 /* max # of disk addrs for fixed allocations */
#ifdef DEBUG
int swpagerdebug = 0x100;
#define SDB_FOLLOW 0x001
#define SDB_INIT 0x002
#define SDB_ALLOC 0x004
#define SDB_IO 0x008
#define SDB_WRITE 0x010
#define SDB_FAIL 0x020
#define SDB_ALLOCBLK 0x040
#define SDB_FULL 0x080
#define SDB_ANOM 0x100
#define SDB_ANOMPANIC 0x200
#endif
struct swpagerclean {
queue_head_t spc_list;
int spc_flags;
struct buf *spc_bp;
sw_pager_t spc_swp;
vm_offset_t spc_kva;
vm_page_t spc_m;
} swcleanlist[NPENDINGIO];
typedef struct swpagerclean *swp_clean_t;
/* spc_flags values */
#define SPC_FREE 0x00
#define SPC_BUSY 0x01
#define SPC_DONE 0x02
#define SPC_ERROR 0x04
#define SPC_DIRTY 0x08
struct swtab {
vm_size_t st_osize; /* size of object (bytes) */
int st_bsize; /* vs. size of swap block (DEV_BSIZE units) */
#ifdef DEBUG
u_long st_inuse; /* number in this range in use */
u_long st_usecnt; /* total used of this size */
#endif
} swtab[NSWSIZES+1];
#ifdef DEBUG
int swap_pager_pendingio; /* max pending async "clean" ops */
int swap_pager_poip; /* pageouts in progress */
int swap_pager_piip; /* pageins in progress */
#endif
queue_head_t swap_pager_inuse; /* list of pending page cleans */
queue_head_t swap_pager_free; /* list of free pager clean structs */
queue_head_t swap_pager_list; /* list of "named" anon regions */
static int swap_pager_finish __P((swp_clean_t));
static void swap_pager_init __P((void));
static vm_pager_t swap_pager_alloc __P((caddr_t, vm_size_t, vm_prot_t));
static boolean_t swap_pager_clean __P((vm_page_t, int));
static void swap_pager_dealloc __P((vm_pager_t));
static int swap_pager_getpage
__P((vm_pager_t, vm_page_t, boolean_t));
static boolean_t swap_pager_haspage __P((vm_pager_t, vm_offset_t));
static int swap_pager_io __P((sw_pager_t, vm_page_t, int));
static void swap_pager_iodone __P((struct buf *));
static int swap_pager_putpage
__P((vm_pager_t, vm_page_t, boolean_t));
struct pagerops swappagerops = {
swap_pager_init,
swap_pager_alloc,
swap_pager_dealloc,
swap_pager_getpage,
swap_pager_putpage,
swap_pager_haspage
};
static void
swap_pager_init()
{
register swp_clean_t spc;
register int i, bsize;
extern int dmmin, dmmax;
int maxbsize;
#ifdef DEBUG
if (swpagerdebug & (SDB_FOLLOW|SDB_INIT))
printf("swpg_init()\n");
#endif
dfltpagerops = &swappagerops;
queue_init(&swap_pager_list);
/*
* Initialize clean lists
*/
queue_init(&swap_pager_inuse);
queue_init(&swap_pager_free);
for (i = 0, spc = swcleanlist; i < NPENDINGIO; i++, spc++) {
queue_enter(&swap_pager_free, spc, swp_clean_t, spc_list);
spc->spc_flags = SPC_FREE;
}
/*
* Calculate the swap allocation constants.
*/
if (dmmin == 0) {
dmmin = DMMIN;
if (dmmin < CLBYTES/DEV_BSIZE)
dmmin = CLBYTES/DEV_BSIZE;
}
if (dmmax == 0)
dmmax = DMMAX;
/*
* Fill in our table of object size vs. allocation size
*/
bsize = btodb(PAGE_SIZE);
if (bsize < dmmin)
bsize = dmmin;
maxbsize = btodb(sizeof(sw_bm_t) * NBBY * PAGE_SIZE);
if (maxbsize > dmmax)
maxbsize = dmmax;
for (i = 0; i < NSWSIZES; i++) {
swtab[i].st_osize = (vm_size_t) (MAXDADDRS * dbtob(bsize));
swtab[i].st_bsize = bsize;
#ifdef DEBUG
if (swpagerdebug & SDB_INIT)
printf("swpg_init: ix %d, size %x, bsize %x\n",
i, swtab[i].st_osize, swtab[i].st_bsize);
#endif
if (bsize >= maxbsize)
break;
bsize *= 2;
}
swtab[i].st_osize = 0;
swtab[i].st_bsize = bsize;
}
/*
* 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.
*/
static vm_pager_t
swap_pager_alloc(handle, size, prot)
caddr_t handle;
register vm_size_t size;
vm_prot_t prot;
{
register vm_pager_t pager;
register sw_pager_t swp;
struct swtab *swt;
int waitok;
#ifdef DEBUG
if (swpagerdebug & (SDB_FOLLOW|SDB_ALLOC))
printf("swpg_alloc(%x, %x, %x)\n", handle, size, prot);
#endif
/*
* 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_NOWAIT;
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) {
#ifdef DEBUG
if (swpagerdebug & SDB_FAIL)
printf("swpg_alloc: swpager malloc failed\n");
#endif
free((caddr_t)pager, M_VMPAGER);
return(NULL);
}
size = round_page(size);
for (swt = swtab; swt->st_osize; swt++)
if (size <= swt->st_osize)
break;
#ifdef DEBUG
swt->st_inuse++;
swt->st_usecnt++;
#endif
swp->sw_osize = size;
swp->sw_bsize = swt->st_bsize;
swp->sw_nblocks = (btodb(size) + swp->sw_bsize - 1) / swp->sw_bsize;
swp->sw_blocks = (sw_blk_t)
malloc(swp->sw_nblocks*sizeof(*swp->sw_blocks),
M_VMPGDATA, M_NOWAIT);
if (swp->sw_blocks == NULL) {
free((caddr_t)swp, M_VMPGDATA);
free((caddr_t)pager, M_VMPAGER);
#ifdef DEBUG
if (swpagerdebug & SDB_FAIL)
printf("swpg_alloc: sw_blocks malloc failed\n");
swt->st_inuse--;
swt->st_usecnt--;
#endif
return(FALSE);
}
bzero((caddr_t)swp->sw_blocks,
swp->sw_nblocks * sizeof(*swp->sw_blocks));
swp->sw_poip = 0;
if (handle) {
vm_object_t object;
swp->sw_flags = SW_NAMED;
queue_enter(&swap_pager_list, pager, vm_pager_t, 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);
vm_object_setpager(object, pager, 0, FALSE);
} else {
swp->sw_flags = 0;
queue_init(&pager->pg_list);
}
pager->pg_handle = handle;
pager->pg_ops = &swappagerops;
pager->pg_type = PG_SWAP;
pager->pg_data = (caddr_t)swp;
#ifdef DEBUG
if (swpagerdebug & SDB_ALLOC)
printf("swpg_alloc: pg_data %x, %x of %x at %x\n",
swp, swp->sw_nblocks, swp->sw_bsize, swp->sw_blocks);
#endif
return(pager);
}
static void
swap_pager_dealloc(pager)
vm_pager_t pager;
{
register int i;
register sw_blk_t bp;
register sw_pager_t swp;
struct swtab *swt;
int s;
#ifdef DEBUG
/* save panic time state */
if ((swpagerdebug & SDB_ANOMPANIC) && panicstr)
return;
if (swpagerdebug & (SDB_FOLLOW|SDB_ALLOC))
printf("swpg_dealloc(%x)\n", pager);
#endif
/*
* Remove from list right away so lookups will fail if we
* block for pageout completion.
*/
swp = (sw_pager_t) pager->pg_data;
if (swp->sw_flags & SW_NAMED) {
queue_remove(&swap_pager_list, pager, vm_pager_t, pg_list);
swp->sw_flags &= ~SW_NAMED;
}
#ifdef DEBUG
for (swt = swtab; swt->st_osize; swt++)
if (swp->sw_osize <= swt->st_osize)
break;
swt->st_inuse--;
#endif
/*
* Wait for all pageouts to finish and remove
* all entries from cleaning list.
*/
s = splbio();
while (swp->sw_poip) {
swp->sw_flags |= SW_WANTED;
assert_wait((int)swp, 0);
thread_block();
}
splx(s);
(void) swap_pager_clean(NULL, B_WRITE);
/*
* Free left over swap blocks
*/
for (i = 0, bp = swp->sw_blocks; i < swp->sw_nblocks; i++, bp++)
if (bp->swb_block) {
#ifdef DEBUG
if (swpagerdebug & (SDB_ALLOCBLK|SDB_FULL))
printf("swpg_dealloc: blk %x\n",
bp->swb_block);
#endif
rmfree(swapmap, swp->sw_bsize, bp->swb_block);
}
/*
* Free swap management resources
*/
free((caddr_t)swp->sw_blocks, M_VMPGDATA);
free((caddr_t)swp, M_VMPGDATA);
free((caddr_t)pager, M_VMPAGER);
}
static int
swap_pager_getpage(pager, m, sync)
vm_pager_t pager;
vm_page_t m;
boolean_t sync;
{
#ifdef DEBUG
if (swpagerdebug & SDB_FOLLOW)
printf("swpg_getpage(%x, %x, %d)\n", pager, m, sync);
#endif
return(swap_pager_io((sw_pager_t)pager->pg_data, m, B_READ));
}
static int
swap_pager_putpage(pager, m, sync)
vm_pager_t pager;
vm_page_t m;
boolean_t sync;
{
int flags;
#ifdef DEBUG
if (swpagerdebug & SDB_FOLLOW)
printf("swpg_putpage(%x, %x, %d)\n", pager, m, sync);
#endif
if (pager == NULL) {
(void) swap_pager_clean(NULL, B_WRITE);
return (VM_PAGER_OK); /* ??? */
}
flags = B_WRITE;
if (!sync)
flags |= B_ASYNC;
return(swap_pager_io((sw_pager_t)pager->pg_data, m, flags));
}
static boolean_t
swap_pager_haspage(pager, offset)
vm_pager_t pager;
vm_offset_t offset;
{
register sw_pager_t swp;
register sw_blk_t swb;
int ix;
#ifdef DEBUG
if (swpagerdebug & (SDB_FOLLOW|SDB_ALLOCBLK))
printf("swpg_haspage(%x, %x) ", pager, offset);
#endif
swp = (sw_pager_t) pager->pg_data;
ix = offset / dbtob(swp->sw_bsize);
if (swp->sw_blocks == NULL || ix >= swp->sw_nblocks) {
#ifdef DEBUG
if (swpagerdebug & (SDB_FAIL|SDB_FOLLOW|SDB_ALLOCBLK))
printf("swpg_haspage: %x bad offset %x, ix %x\n",
swp->sw_blocks, offset, ix);
#endif
return(FALSE);
}
swb = &swp->sw_blocks[ix];
if (swb->swb_block)
ix = atop(offset % dbtob(swp->sw_bsize));
#ifdef DEBUG
if (swpagerdebug & SDB_ALLOCBLK)
printf("%x blk %x+%x ", swp->sw_blocks, swb->swb_block, ix);
if (swpagerdebug & (SDB_FOLLOW|SDB_ALLOCBLK))
printf("-> %c\n",
"FT"[swb->swb_block && (swb->swb_mask & (1 << ix))]);
#endif
if (swb->swb_block && (swb->swb_mask & (1 << ix)))
return(TRUE);
return(FALSE);
}
/*
* Scaled down version of swap().
* Assumes that PAGE_SIZE < MAXPHYS; i.e. only one operation needed.
* BOGUS: lower level IO routines expect a KVA so we have to map our
* provided physical page into the KVA to keep them happy.
*/
static int
swap_pager_io(swp, m, flags)
register sw_pager_t swp;
vm_page_t m;
int flags;
{
register struct buf *bp;
register sw_blk_t swb;
register int s;
int ix;
boolean_t rv;
vm_offset_t kva, off;
swp_clean_t spc;
#ifdef DEBUG
/* save panic time state */
if ((swpagerdebug & SDB_ANOMPANIC) && panicstr)
return (VM_PAGER_FAIL); /* XXX: correct return? */
if (swpagerdebug & (SDB_FOLLOW|SDB_IO))
printf("swpg_io(%x, %x, %x)\n", swp, m, flags);
#endif
/*
* For reads (pageins) and synchronous writes, we clean up
* all completed async pageouts.
*/
if ((flags & B_ASYNC) == 0) {
s = splbio();
#ifdef DEBUG
/*
* Check to see if this page is currently being cleaned.
* If it is, we just wait til the operation is done before
* continuing.
*/
while (swap_pager_clean(m, flags&B_READ)) {
if (swpagerdebug & SDB_ANOM)
printf("swap_pager_io: page %x cleaning\n", m);
swp->sw_flags |= SW_WANTED;
assert_wait((int)swp, 0);
thread_block();
}
#else
(void) swap_pager_clean(m, flags&B_READ);
#endif
splx(s);
}
/*
* For async writes (pageouts), we cleanup completed pageouts so
* that all available resources are freed. Also tells us if this
* page is already being cleaned. If it is, or no resources
* are available, we try again later.
*/
else if (swap_pager_clean(m, B_WRITE) ||
queue_empty(&swap_pager_free)) {
#ifdef DEBUG
if ((swpagerdebug & SDB_ANOM) &&
!queue_empty(&swap_pager_free))
printf("swap_pager_io: page %x already cleaning\n", m);
#endif
return(VM_PAGER_FAIL);
}
/*
* Determine swap block and allocate as necessary.
*/
off = m->offset + m->object->paging_offset;
ix = off / dbtob(swp->sw_bsize);
if (swp->sw_blocks == NULL || ix >= swp->sw_nblocks) {
#ifdef DEBUG
if (swpagerdebug & SDB_FAIL)
printf("swpg_io: bad offset %x+%x(%d) in %x\n",
m->offset, m->object->paging_offset,
ix, swp->sw_blocks);
#endif
return(VM_PAGER_FAIL);
}
swb = &swp->sw_blocks[ix];
off = off % dbtob(swp->sw_bsize);
if (flags & B_READ) {
if (swb->swb_block == 0 ||
(swb->swb_mask & (1 << atop(off))) == 0) {
#ifdef DEBUG
if (swpagerdebug & (SDB_ALLOCBLK|SDB_FAIL))
printf("swpg_io: %x bad read: blk %x+%x, mask %x, off %x+%x\n",
swp->sw_blocks,
swb->swb_block, atop(off),
swb->swb_mask,
m->offset, m->object->paging_offset);
#endif
/* XXX: should we zero page here?? */
return(VM_PAGER_FAIL);
}
} else if (swb->swb_block == 0) {
swb->swb_block = rmalloc(swapmap, swp->sw_bsize);
if (swb->swb_block == 0) {
#ifdef DEBUG
if (swpagerdebug & SDB_FAIL)
printf("swpg_io: rmalloc of %x failed\n",
swp->sw_bsize);
#endif
return(VM_PAGER_FAIL);
}
#ifdef DEBUG
if (swpagerdebug & (SDB_FULL|SDB_ALLOCBLK))
printf("swpg_io: %x alloc blk %x at ix %x\n",
swp->sw_blocks, swb->swb_block, ix);
#endif
}
/*
* Allocate a kernel virtual address and initialize so that PTE
* is available for lower level IO drivers.
*/
kva = vm_pager_map_page(m);
/*
* Get a swap buffer header and perform the IO
*/
s = splbio();
while (bswlist.b_actf == NULL) {
#ifdef DEBUG
if (swpagerdebug & SDB_ANOM)
printf("swap_pager_io: wait on swbuf for %x (%d)\n",
m, flags);
#endif
bswlist.b_flags |= B_WANTED;
sleep((caddr_t)&bswlist, PSWP+1);
}
bp = bswlist.b_actf;
bswlist.b_actf = bp->b_actf;
splx(s);
bp->b_flags = B_BUSY | (flags & B_READ);
bp->b_proc = &proc0; /* XXX (but without B_PHYS set this is ok) */
bp->b_un.b_addr = (caddr_t)kva;
bp->b_blkno = swb->swb_block + btodb(off);
VHOLD(swapdev_vp);
bp->b_vp = swapdev_vp;
if (swapdev_vp->v_type == VBLK)
bp->b_dev = swapdev_vp->v_rdev;
bp->b_bcount = PAGE_SIZE;
if ((bp->b_flags & B_READ) == 0) {
bp->b_dirtyoff = 0;
bp->b_dirtyend = PAGE_SIZE;
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.
*/
if ((flags & (B_READ|B_ASYNC)) == B_ASYNC) {
#ifdef DEBUG
if (queue_empty(&swap_pager_free))
panic("swpg_io: lost spc");
#endif
queue_remove_first(&swap_pager_free,
spc, swp_clean_t, spc_list);
#ifdef DEBUG
if (spc->spc_flags != SPC_FREE)
panic("swpg_io: bad free spc");
#endif
spc->spc_flags = SPC_BUSY;
spc->spc_bp = bp;
spc->spc_swp = swp;
spc->spc_kva = kva;
spc->spc_m = m;
bp->b_flags |= B_CALL;
bp->b_iodone = swap_pager_iodone;
s = splbio();
swp->sw_poip++;
queue_enter(&swap_pager_inuse, spc, swp_clean_t, spc_list);
#ifdef DEBUG
swap_pager_poip++;
if (swpagerdebug & SDB_WRITE)
printf("swpg_io: write: bp=%x swp=%x spc=%x poip=%d\n",
bp, swp, spc, swp->sw_poip);
if ((swpagerdebug & SDB_ALLOCBLK) &&
(swb->swb_mask & (1 << atop(off))) == 0)
printf("swpg_io: %x write blk %x+%x\n",
swp->sw_blocks, swb->swb_block, atop(off));
#endif
swb->swb_mask |= (1 << atop(off));
splx(s);
}
#ifdef DEBUG
if (swpagerdebug & SDB_IO)
printf("swpg_io: IO start: bp %x, db %x, va %x, pa %x\n",
bp, swb->swb_block+btodb(off), kva, VM_PAGE_TO_PHYS(m));
#endif
VOP_STRATEGY(bp);
if ((flags & (B_READ|B_ASYNC)) == B_ASYNC) {
#ifdef DEBUG
if (swpagerdebug & SDB_IO)
printf("swpg_io: IO started: bp %x\n", bp);
#endif
return(VM_PAGER_PEND);
}
s = splbio();
#ifdef DEBUG
if (flags & B_READ)
swap_pager_piip++;
else
swap_pager_poip++;
#endif
while ((bp->b_flags & B_DONE) == 0) {
assert_wait((int)bp, 0);
thread_block();
}
#ifdef DEBUG
if (flags & B_READ)
--swap_pager_piip;
else
--swap_pager_poip;
#endif
rv = (bp->b_flags & B_ERROR) ? VM_PAGER_ERROR : VM_PAGER_OK;
bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY);
bp->b_actf = bswlist.b_actf;
bswlist.b_actf = bp;
if (bp->b_vp)
brelvp(bp);
if (bswlist.b_flags & B_WANTED) {
bswlist.b_flags &= ~B_WANTED;
thread_wakeup((int)&bswlist);
}
if ((flags & B_READ) == 0 && rv == VM_PAGER_OK) {
m->flags |= PG_CLEAN;
pmap_clear_modify(VM_PAGE_TO_PHYS(m));
}
splx(s);
#ifdef DEBUG
if (swpagerdebug & SDB_IO)
printf("swpg_io: IO done: bp %x, rv %d\n", bp, rv);
if ((swpagerdebug & SDB_FAIL) && rv == VM_PAGER_ERROR)
printf("swpg_io: IO error\n");
#endif
vm_pager_unmap_page(kva);
return(rv);
}
static boolean_t
swap_pager_clean(m, rw)
vm_page_t m;
int rw;
{
register swp_clean_t spc, tspc;
register int s;
#ifdef DEBUG
/* save panic time state */
if ((swpagerdebug & SDB_ANOMPANIC) && panicstr)
return (FALSE); /* ??? */
if (swpagerdebug & SDB_FOLLOW)
printf("swpg_clean(%x, %d)\n", m, rw);
#endif
tspc = NULL;
for (;;) {
/*
* Look up and removal from inuse list must be done
* at splbio() to avoid conflicts with swap_pager_iodone.
*/
s = splbio();
spc = (swp_clean_t) queue_first(&swap_pager_inuse);
while (!queue_end(&swap_pager_inuse, (queue_entry_t)spc)) {
if ((spc->spc_flags & SPC_DONE) &&
swap_pager_finish(spc)) {
queue_remove(&swap_pager_inuse, spc,
swp_clean_t, spc_list);
break;
}
if (m && m == spc->spc_m) {
#ifdef DEBUG
if (swpagerdebug & SDB_ANOM)
printf("swap_pager_clean: page %x on list, flags %x\n",
m, spc->spc_flags);
#endif
tspc = spc;
}
spc = (swp_clean_t) queue_next(&spc->spc_list);
}
/*
* No operations done, thats all we can do for now.
*/
if (queue_end(&swap_pager_inuse, (queue_entry_t)spc))
break;
splx(s);
/*
* The desired page was found to be busy earlier in
* the scan but has since completed.
*/
if (tspc && tspc == spc) {
#ifdef DEBUG
if (swpagerdebug & SDB_ANOM)
printf("swap_pager_clean: page %x done while looking\n",
m);
#endif
tspc = NULL;
}
spc->spc_flags = SPC_FREE;
vm_pager_unmap_page(spc->spc_kva);
queue_enter(&swap_pager_free, spc, swp_clean_t, spc_list);
#ifdef DEBUG
if (swpagerdebug & SDB_WRITE)
printf("swpg_clean: free spc %x\n", spc);
#endif
}
#ifdef DEBUG
/*
* If we found that the desired page is already being cleaned
* mark it so that swap_pager_iodone() will not set the clean
* flag before the pageout daemon has another chance to clean it.
*/
if (tspc && rw == B_WRITE) {
if (swpagerdebug & SDB_ANOM)
printf("swap_pager_clean: page %x on clean list\n",
tspc);
tspc->spc_flags |= SPC_DIRTY;
}
#endif
splx(s);
#ifdef DEBUG
if (swpagerdebug & SDB_WRITE)
printf("swpg_clean: return %d\n", tspc ? TRUE : FALSE);
if ((swpagerdebug & SDB_ANOM) && tspc)
printf("swpg_clean: %s of cleaning page %x\n",
rw == B_READ ? "get" : "put", m);
#endif
return(tspc ? TRUE : FALSE);
}
static int
swap_pager_finish(spc)
register swp_clean_t spc;
{
vm_object_t object = spc->spc_m->object;
/*
* Mark the paging operation as done.
* (XXX) If we cannot get the lock, leave it til later.
* (XXX) Also we are assuming that an async write is a
* pageout operation that has incremented the counter.
*/
if (!vm_object_lock_try(object))
return(0);
if (--object->paging_in_progress == 0)
thread_wakeup((int) object);
#ifdef DEBUG
/*
* XXX: this isn't even close to the right thing to do,
* introduces a variety of race conditions.
*
* If dirty, vm_pageout() has attempted to clean the page
* again. In this case we do not do anything as we will
* see the page again shortly.
*/
if (spc->spc_flags & SPC_DIRTY) {
if (swpagerdebug & SDB_ANOM)
printf("swap_pager_finish: page %x dirty again\n",
spc->spc_m);
spc->spc_m->flags &= ~PG_BUSY;
PAGE_WAKEUP(spc->spc_m);
vm_object_unlock(object);
return(1);
}
#endif
/*
* 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) {
printf("swap_pager_finish: clean of page %x failed\n",
VM_PAGE_TO_PHYS(spc->spc_m));
spc->spc_m->flags |= PG_LAUNDRY;
} else {
spc->spc_m->flags |= PG_CLEAN;
pmap_clear_modify(VM_PAGE_TO_PHYS(spc->spc_m));
}
spc->spc_m->flags &= ~PG_BUSY;
PAGE_WAKEUP(spc->spc_m);
vm_object_unlock(object);
return(1);
}
static void
swap_pager_iodone(bp)
register struct buf *bp;
{
register swp_clean_t spc;
daddr_t blk;
int s;
#ifdef DEBUG
/* save panic time state */
if ((swpagerdebug & SDB_ANOMPANIC) && panicstr)
return;
if (swpagerdebug & SDB_FOLLOW)
printf("swpg_iodone(%x)\n", bp);
#endif
s = splbio();
spc = (swp_clean_t) queue_first(&swap_pager_inuse);
while (!queue_end(&swap_pager_inuse, (queue_entry_t)spc)) {
if (spc->spc_bp == bp)
break;
spc = (swp_clean_t) queue_next(&spc->spc_list);
}
#ifdef DEBUG
if (queue_end(&swap_pager_inuse, (queue_entry_t)spc))
panic("swap_pager_iodone: bp not found");
#endif
spc->spc_flags &= ~SPC_BUSY;
spc->spc_flags |= SPC_DONE;
if (bp->b_flags & B_ERROR)
spc->spc_flags |= SPC_ERROR;
spc->spc_bp = NULL;
blk = bp->b_blkno;
#ifdef DEBUG
--swap_pager_poip;
if (swpagerdebug & SDB_WRITE)
printf("swpg_iodone: bp=%x swp=%x flags=%x spc=%x poip=%x\n",
bp, spc->spc_swp, spc->spc_swp->sw_flags,
spc, spc->spc_swp->sw_poip);
#endif
spc->spc_swp->sw_poip--;
if (spc->spc_swp->sw_flags & SW_WANTED) {
spc->spc_swp->sw_flags &= ~SW_WANTED;
thread_wakeup((int)spc->spc_swp);
}
bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY);
bp->b_actf = bswlist.b_actf;
bswlist.b_actf = bp;
if (bp->b_vp)
brelvp(bp);
if (bswlist.b_flags & B_WANTED) {
bswlist.b_flags &= ~B_WANTED;
thread_wakeup((int)&bswlist);
}
/*
* Only kick the pageout daemon if we are really hurting
* for pages, otherwise this page will be picked up later.
*/
if (cnt.v_free_count < cnt.v_free_min)
thread_wakeup((int) &vm_pages_needed);
splx(s);
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.