d/freebsd-nq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Mostly superficial code improvements, add a diagnostic. The

Browse Source 
code improvements include significant simplification of the reservation
of the swap pager control blocks for reads.  Add a panic for an inconsistent
swap pager control block count.
This commit is contained in:
John Dyson 1996-06-10 04:58:48 +00:00
parent f57be23b1f
commit 3091ee0955
1 changed files with 23 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
sys/vm/swap_pager.c
View File

@ -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 1.66 1996/05/18 03:37:32 dyson Exp $
* $Id: swap_pager.c,v 1.67 1996/05/23 00:45:50 dyson Exp $
*/
/*
@ -112,6 +112,7 @@ static struct swpclean swap_pager_inuse;
/* list of free pager clean structs */
static struct swpclean swap_pager_free;
int swap_pager_free_count;
/* list of "named" anon region objects */
static struct pagerlst swap_pager_object_list;
@ -204,6 +205,7 @@ swap_pager_init()
TAILQ_INIT(&swap_pager_inuse);
TAILQ_INIT(&swap_pager_done);
TAILQ_INIT(&swap_pager_free);
swap_pager_free_count = 0;
/*
* Calculate the swap allocation constants.
@ -235,6 +237,7 @@ swap_pager_swap_init()
}
spc->spc_flags = 0;
TAILQ_INSERT_TAIL(&swap_pager_free, spc, spc_list);
swap_pager_free_count++;
}
}
@ -980,11 +983,10 @@ swap_pager_getpages(object, m, count, reqpage)
* into "m" for the page actually faulted
*/
spc = NULL; /* we might not use an spc data structure */
if ((count == 1) && (TAILQ_FIRST(&swap_pager_free) != NULL)) {
spc = TAILQ_FIRST(&swap_pager_free);
spc = NULL;
if ((count == 1) && ((spc = TAILQ_FIRST(&swap_pager_free)) != NULL)) {
TAILQ_REMOVE(&swap_pager_free, spc, spc_list);
swap_pager_free_count--;
kva = spc->spc_kva;
bp = spc->spc_bp;
bzero(bp, sizeof *bp);
@ -1028,7 +1030,10 @@ swap_pager_getpages(object, m, count, reqpage)
*/
s = splbio();
while ((bp->b_flags & B_DONE) == 0) {
tsleep(bp, PVM, "swread", 0);
if (tsleep(bp, PVM, "swread", hz*20)) {
printf("swap_pager: indefinite wait buffer: device: %d, blkno: %d, size: %d\n",
bp->b_dev, bp->b_blkno, bp->b_bcount);
}
}
if (bp->b_flags & B_ERROR) {
@ -1065,6 +1070,7 @@ swap_pager_getpages(object, m, count, reqpage)
if (bp->b_wcred != NOCRED)
crfree(bp->b_wcred);
TAILQ_INSERT_TAIL(&swap_pager_free, spc, spc_list);
swap_pager_free_count++;
if (swap_pager_needflags & SWAP_FREE_NEEDED) {
wakeup(&swap_pager_free);
}
@ -1289,9 +1295,7 @@ swap_pager_putpages(object, m, count, sync, rtvals)
/*
* get a swap pager clean data structure, block until we get it
*/
if (TAILQ_FIRST(&swap_pager_free) == NULL ||
TAILQ_NEXT(TAILQ_FIRST(&swap_pager_free),spc_list) == NULL ||
TAILQ_NEXT(TAILQ_NEXT(TAILQ_FIRST(&swap_pager_free),spc_list),spc_list) == NULL) {
if (swap_pager_free_count <= 3) {
s = splbio();
if (curproc == pageproc) {
retryfree:
@ -1311,9 +1315,7 @@ swap_pager_putpages(object, m, count, sync, rtvals)
*/
if (tsleep(&swap_pager_free, PVM, "swpfre", hz/5)) {
swap_pager_sync();
if (TAILQ_FIRST(&swap_pager_free) == NULL ||
TAILQ_NEXT(TAILQ_FIRST(&swap_pager_free),spc_list) == NULL ||
TAILQ_NEXT(TAILQ_NEXT(TAILQ_FIRST(&swap_pager_free),spc_list),spc_list) == NULL) {
if (swap_pager_free_count <= 3) {
splx(s);
return VM_PAGER_AGAIN;
}
@ -1323,17 +1325,13 @@ swap_pager_putpages(object, m, count, sync, rtvals)
* the free swap control blocks.
*/
swap_pager_sync();
if (TAILQ_FIRST(&swap_pager_free) == NULL ||
TAILQ_NEXT(TAILQ_FIRST(&swap_pager_free),spc_list) == NULL ||
TAILQ_NEXT(TAILQ_NEXT(TAILQ_FIRST(&swap_pager_free),spc_list),spc_list) == NULL) {
if (swap_pager_free_count <= 3) {
goto retryfree;
}
}
} else {
pagedaemon_wakeup();
while (TAILQ_FIRST(&swap_pager_free) == NULL ||
TAILQ_NEXT(TAILQ_FIRST(&swap_pager_free),spc_list) == NULL ||
TAILQ_NEXT(TAILQ_NEXT(TAILQ_FIRST(&swap_pager_free),spc_list),spc_list) == NULL) {
while (swap_pager_free_count <= 3) {
swap_pager_needflags |= SWAP_FREE_NEEDED;
tsleep(&swap_pager_free, PVM, "swpfre", 0);
pagedaemon_wakeup();
@ -1342,7 +1340,10 @@ swap_pager_putpages(object, m, count, sync, rtvals)
splx(s);
}
spc = TAILQ_FIRST(&swap_pager_free);
if (spc == NULL)
panic("swap_pager_putpages: free queue is empty, %d expected\n", swap_pager_free_count);
TAILQ_REMOVE(&swap_pager_free, spc, spc_list);
swap_pager_free_count--;
kva = spc->spc_kva;
@ -1492,6 +1493,7 @@ swap_pager_putpages(object, m, count, sync, rtvals)
if (bp->b_wcred != NOCRED)
crfree(bp->b_wcred);
TAILQ_INSERT_TAIL(&swap_pager_free, spc, spc_list);
swap_pager_free_count++;
if (swap_pager_needflags & SWAP_FREE_NEEDED) {
wakeup(&swap_pager_free);
}
@ -1540,6 +1542,7 @@ swap_pager_sync()
}
spc->spc_flags = 0;
TAILQ_INSERT_TAIL(&swap_pager_free, spc, spc_list);
swap_pager_free_count++;
if (swap_pager_needflags & SWAP_FREE_NEEDED) {
wakeup(&swap_pager_free);
}
@ -1622,7 +1625,9 @@ swap_pager_iodone(bp)
if (bp->b_vp)
pbrelvp(bp);
/*
if (bp->b_flags & B_WANTED)
*/
wakeup(bp);
if (bp->b_rcred != NOCRED)