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Fixed bugs in accounting of swap space that resulted in the pager thinking

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it was out of space when it really wasn't.

Submitted by:	John Dyson
This commit is contained in:
David Greenman 1994-11-13 15:36:48 +00:00
parent bfbfac11c9
commit 24ea4a9671
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=4440
1 changed files with 19 additions and 62 deletions
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81
sys/vm/swap_pager.c
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@ -39,7 +39,7 @@
* 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 1.16 1994/10/25 07:06:20 davidg Exp $
* $Id: swap_pager.c,v 1.17 1994/11/06 09:55:28 davidg Exp $
*/
/*
@ -79,6 +79,7 @@ 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;
@ -141,8 +142,6 @@ int dmmin, dmmax;
extern int vm_page_count;
static inline void swapsizecheck() {
if( vm_swap_size == 0)
return;
if( vm_swap_size < 128*btodb(PAGE_SIZE)) {
if( swap_pager_full)
printf("swap_pager: out of space\n");
@ -237,12 +236,6 @@ swap_pager_alloc(handle, size, prot, offset)
}
}
/*
if (swap_pager_full && (vm_swap_size == 0)) {
return(NULL);
}
*/
/*
* Pager doesn't exist, allocate swap management resources
* and initialize.
@ -361,23 +354,14 @@ swap_pager_setvalid(swp, offset, valid)
*/
int
swap_pager_getswapspace( unsigned amount, unsigned *rtval) {
#ifdef EXP
unsigned tmpalloc;
unsigned nblocksfrag = btodb(SWB_NPAGES*PAGE_SIZE);
if( amount < nblocksfrag) {
if( rlist_alloc(&swapfrag, amount, rtval))
return 1;
if( !rlist_alloc(&swaplist, nblocksfrag, &tmpalloc))
return 0;
rlist_free( &swapfrag, tmpalloc+amount, tmpalloc + nblocksfrag - 1);
*rtval = tmpalloc;
vm_swap_size -= amount;
if( !rlist_alloc(&swaplist, amount, rtval)) {
vm_swap_size += amount;
return 0;
} else {
swapsizecheck();
return 1;
}
#endif
if( !rlist_alloc(&swaplist, amount, rtval))
return 0;
else
return 1;
}
/*
@ -386,20 +370,9 @@ swap_pager_getswapspace( unsigned amount, unsigned *rtval) {
*/
void
swap_pager_freeswapspace( unsigned from, unsigned to) {
#ifdef EXP
unsigned nblocksfrag = btodb(SWB_NPAGES*PAGE_SIZE);
unsigned tmpalloc;
if( ((to + 1) - from) >= nblocksfrag) {
#endif
rlist_free(&swaplist, from, to);
#ifdef EXP
return;
}
rlist_free(&swapfrag, from, to);
while( rlist_alloc(&swapfrag, nblocksfrag, &tmpalloc)) {
rlist_free(&swaplist, tmpalloc, tmpalloc + nblocksfrag-1);
}
#endif
rlist_free(&swaplist, from, to);
vm_swap_size += (to-from)+1;
swapsizecheck();
}
/*
* this routine frees swap blocks from a specified pager
@ -420,13 +393,11 @@ _swap_pager_freespace(swp, start, size)
if (addr && *addr != SWB_EMPTY) {
swap_pager_freeswapspace(*addr, *addr+btodb(PAGE_SIZE) - 1);
if( valid) {
vm_swap_size += btodb(PAGE_SIZE);
swap_pager_setvalid(swp, i, 0);
}
*addr = SWB_EMPTY;
}
}
swapsizecheck();
splx(s);
}
@ -511,7 +482,6 @@ swap_pager_reclaim()
*/
for (i = 0; i < reclaimcount; i++) {
swap_pager_freeswapspace(reclaims[i], reclaims[i]+btodb(PAGE_SIZE) - 1);
swapsizecheck();
wakeup((caddr_t) &in_reclaim);
}
@ -538,7 +508,10 @@ swap_pager_copy(srcpager, srcoffset, dstpager, dstoffset, offset)
vm_offset_t i;
int s;
if( vm_swap_size == 0)
if( vm_swap_size)
no_swap_space = 0;
if( no_swap_space)
return;
srcswp = (sw_pager_t) srcpager->pg_data;
@ -575,9 +548,6 @@ swap_pager_copy(srcpager, srcoffset, dstpager, dstoffset, offset)
int *addr = swap_pager_diskaddr(srcswp, i, &valid);
if (addr && *addr != SWB_EMPTY) {
swap_pager_freeswapspace(*addr, *addr+btodb(PAGE_SIZE) - 1);
if( valid)
vm_swap_size += btodb(PAGE_SIZE);
swapsizecheck();
*addr = SWB_EMPTY;
}
}
@ -611,7 +581,6 @@ swap_pager_copy(srcpager, srcoffset, dstpager, dstoffset, offset)
*dstaddrp = *srcaddrp;
*srcaddrp = SWB_EMPTY;
swap_pager_setvalid(dstswp, i + dstoffset, 1);
vm_swap_size -= btodb(PAGE_SIZE);
}
}
/*
@ -619,8 +588,6 @@ swap_pager_copy(srcpager, srcoffset, dstpager, dstoffset, offset)
*/
if (*srcaddrp != SWB_EMPTY) {
swap_pager_freeswapspace(*srcaddrp, *srcaddrp+btodb(PAGE_SIZE) - 1);
if( srcvalid)
vm_swap_size += btodb(PAGE_SIZE);
*srcaddrp = SWB_EMPTY;
}
}
@ -634,13 +601,10 @@ swap_pager_copy(srcpager, srcoffset, dstpager, dstoffset, offset)
int *srcaddrp = swap_pager_diskaddr(srcswp, i, &valid);
if (srcaddrp && *srcaddrp != SWB_EMPTY) {
swap_pager_freeswapspace(*srcaddrp, *srcaddrp+btodb(PAGE_SIZE) - 1);
if( valid)
vm_swap_size += btodb(PAGE_SIZE);
*srcaddrp = SWB_EMPTY;
}
}
swapsizecheck();
splx(s);
free((caddr_t)srcswp->sw_blocks, M_VMPGDATA);
@ -696,13 +660,10 @@ swap_pager_dealloc(pager)
if (bp->swb_block[j] != SWB_EMPTY) {
swap_pager_freeswapspace((unsigned)bp->swb_block[j],
(unsigned)bp->swb_block[j] + btodb(PAGE_SIZE) - 1);
if( bp->swb_valid & (1<<j))
vm_swap_size += btodb(PAGE_SIZE);
bp->swb_block[j] = SWB_EMPTY;
}
}
splx(s);
swapsizecheck();
/*
* Free swap management resources
@ -1218,7 +1179,9 @@ swap_pager_output(swp, m, count, flags, rtvals)
if( count > 1)
printf("off: 0x%x, count: %d\n", m[0]->offset, count);
*/
if( vm_swap_size == 0) {
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;
@ -1298,6 +1261,7 @@ swap_pager_output(swp, m, count, flags, rtvals)
}
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);
@ -1415,13 +1379,6 @@ swap_pager_output(swp, m, count, flags, rtvals)
for(i=0;i<count;i++) {
foff = m[i]->offset + paging_offset;
off = swap_pager_block_offset(swp, foff);
/*
* if we are setting the valid bit anew,
* then diminish the swap free space
*/
if( (swb[i]->swb_valid & (1 << off)) == 0)
vm_swap_size -= btodb(PAGE_SIZE);
/*
* set the valid bit
*/