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o Acquire the page queues lock before checking the page's busy status

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in vm_page_grab().  Also, replace the nearby tsleep() with an msleep()
   on the page queues lock.
This commit is contained in:
alc 2002-08-04 19:05:20 +00:00
parent 121bfa6774
commit 8cb1263e6c
1 changed files with 4 additions and 2 deletions
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6
sys/vm/vm_page.c
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@ -1542,6 +1542,7 @@ vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
GIANT_REQUIRED;
retrylookup:
if ((m = vm_page_lookup(object, pindex)) != NULL) {
vm_page_lock_queues();
if (m->busy || (m->flags & PG_BUSY)) {
generation = object->generation;
@ -1549,16 +1550,17 @@ vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
while ((object->generation == generation) &&
(m->busy || (m->flags & PG_BUSY))) {
vm_page_flag_set(m, PG_WANTED | PG_REFERENCED);
tsleep(m, PVM, "pgrbwt", 0);
msleep(m, &vm_page_queue_mtx, PVM, "pgrbwt", 0);
if ((allocflags & VM_ALLOC_RETRY) == 0) {
vm_page_unlock_queues();
splx(s);
return NULL;
}
}
vm_page_unlock_queues();
splx(s);
goto retrylookup;
} else {
vm_page_lock_queues();
if (allocflags & VM_ALLOC_WIRED)
vm_page_wire(m);
vm_page_busy(m);