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Continue the transition from synchronizing access to the page's PG_BUSY

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flag and busy field with the global page queues lock to synchronizing their
access with the containing object's lock.  Specifically, acquire the
containing object's lock before reading the page's PG_BUSY flag and busy
field in vm_fault().

Reviewed by: tegge@
This commit is contained in:
alc 2004-12-24 19:31:54 +00:00
parent 79e7f827b7
commit 6ac766c4df
1 changed files with 29 additions and 11 deletions
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40
sys/vm/vm_fault.c
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@ -148,7 +148,7 @@ unlock_map(struct faultstate *fs)
}
static void
_unlock_things(struct faultstate *fs, int dealloc)
unlock_and_deallocate(struct faultstate *fs)
{
vm_object_pip_wakeup(fs->object);
@ -162,9 +162,7 @@ _unlock_things(struct faultstate *fs, int dealloc)
VM_OBJECT_UNLOCK(fs->first_object);
fs->first_m = NULL;
}
if (dealloc) {
vm_object_deallocate(fs->first_object);
}
vm_object_deallocate(fs->first_object);
unlock_map(fs);
if (fs->vp != NULL) {
mtx_lock(&Giant);
@ -172,13 +170,10 @@ _unlock_things(struct faultstate *fs, int dealloc)
mtx_unlock(&Giant);
fs->vp = NULL;
}
if (dealloc && !fs->map->system_map)
if (!fs->map->system_map)
VM_UNLOCK_GIANT();
}
#define unlock_things(fs) _unlock_things(fs, 0)
#define unlock_and_deallocate(fs) _unlock_things(fs, 1)
/*
* TRYPAGER - used by vm_fault to calculate whether the pager for the
* current object *might* contain the page.
@ -367,10 +362,33 @@ RetryFault:;
*/
if ((fs.m->flags & PG_BUSY) || fs.m->busy) {
vm_page_unlock_queues();
unlock_things(&fs);
vm_page_lock_queues();
if (!vm_page_sleep_if_busy(fs.m, TRUE, "vmpfw"))
VM_OBJECT_UNLOCK(fs.object);
if (fs.object != fs.first_object) {
VM_OBJECT_LOCK(fs.first_object);
vm_page_lock_queues();
vm_page_free(fs.first_m);
vm_page_unlock_queues();
vm_object_pip_wakeup(fs.first_object);
VM_OBJECT_UNLOCK(fs.first_object);
fs.first_m = NULL;
}
unlock_map(&fs);
if (fs.vp != NULL) {
mtx_lock(&Giant);
vput(fs.vp);
mtx_unlock(&Giant);
fs.vp = NULL;
}
VM_OBJECT_LOCK(fs.object);
if (fs.m == vm_page_lookup(fs.object,
fs.pindex)) {
vm_page_lock_queues();
if (!vm_page_sleep_if_busy(fs.m, TRUE,
"vmpfw"))
vm_page_unlock_queues();
}
vm_object_pip_wakeup(fs.object);
VM_OBJECT_UNLOCK(fs.object);
atomic_add_int(&cnt.v_intrans, 1);
if (!fs.map->system_map)
VM_UNLOCK_GIANT();