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Reviewed by: Alan Cox <alc@cs.rice.edu>

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Fix problem w/ low-swap/low-memory handling as reported by Bruce Evans.
This commit is contained in:
Matthew Dillon 1999-02-21 08:30:49 +00:00
parent d6f468efd9
commit 20d3034f39
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=44178
1 changed files with 15 additions and 9 deletions
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24
sys/vm/swap_pager.c
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@ -64,7 +64,7 @@
*
* @(#)swap_pager.c 8.9 (Berkeley) 3/21/94
*
* $Id: swap_pager.c,v 1.113 1999/02/06 07:22:21 dillon Exp $
* $Id: swap_pager.c,v 1.114 1999/02/18 19:57:33 dillon Exp $
*/
#include <sys/param.h>
@ -106,7 +106,8 @@
extern int vm_swap_size; /* number of free swap blocks, in pages */
int swap_pager_full; /* swap space exhaustion (w/ hysteresis)*/
int swap_pager_full; /* swap space exhaustion (task killing) */
static int swap_pager_almost_full; /* swap space exhaustion (w/ hysteresis)*/
static int nsw_rcount; /* free read buffers */
static int nsw_wcount_sync; /* limit write buffers / synchronous */
static int nsw_wcount_async; /* limit write buffers / asynchronous */
@ -184,8 +185,8 @@ struct pagerops swappagerops = {
int dmmax;
static int dmmax_mask;
int nswap_lowat = 128; /* in pages, swap_pager_full warning */
int nswap_hiwat = 512; /* in pages, swap_pager_full warning */
int nswap_lowat = 128; /* in pages, swap_pager_almost_full warn */
int nswap_hiwat = 512; /* in pages, swap_pager_almost_full warn */
static __inline void swp_sizecheck __P((void));
static void swp_pager_sync_iodone __P((struct buf *bp));
@ -210,8 +211,10 @@ static daddr_t swp_pager_meta_ctl __P((vm_object_t, vm_pindex_t, int));
/*
* SWP_SIZECHECK() - update swap_pager_full indication
*
* update the swap_pager_full indication and warn when we are
* about to run out of swap space.
* update the swap_pager_almost_full indication and warn when we are
* about to run out of swap space, using lowat/hiwat hysteresis.
*
* Clear swap_pager_full ( task killing ) indication when lowat is met.
*
* No restrictions on call
* This routine may not block.
@ -222,12 +225,14 @@ static __inline void
swp_sizecheck()
{
if (vm_swap_size < nswap_lowat) {
if (swap_pager_full == 0) {
if (swap_pager_almost_full == 0) {
printf("swap_pager: out of swap space\n");
swap_pager_full = 1;
swap_pager_almost_full = 1;
}
} else if (vm_swap_size > nswap_hiwat) {
} else {
swap_pager_full = 0;
if (vm_swap_size > nswap_hiwat)
swap_pager_almost_full = 0;
}
}
@ -480,6 +485,7 @@ swp_pager_getswapspace(npages)
if (swap_pager_full != 2) {
printf("swap_pager_getswapspace: failed\n");
swap_pager_full = 2;
swap_pager_almost_full = 1;
}
} else {
vm_swap_size -= npages;