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Optimize vm_object_terminate().

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Reviewed by:	kib
MFC after:	1 week
This commit is contained in:
Alan Cox 2010-11-20 22:30:09 +00:00
parent 61381fcf2d
commit 17ea6f00d5
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=215597
1 changed files with 28 additions and 9 deletions
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37
sys/vm/vm_object.c
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@ -661,7 +661,7 @@ vm_object_destroy(vm_object_t object)
void
vm_object_terminate(vm_object_t object)
{
vm_page_t p;
vm_page_t p, p_next;
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
@ -701,22 +701,41 @@ vm_object_terminate(vm_object_t object)
object->ref_count));
/*
* Now free any remaining pages. For internal objects, this also
* removes them from paging queues. Don't free wired pages, just
* remove them from the object.
* Free any remaining pageable pages. This also removes them from the
* paging queues. However, don't free wired pages, just remove them
* from the object. Rather than incrementally removing each page from
* the object, the page and object are reset to any empty state.
*/
while ((p = TAILQ_FIRST(&object->memq)) != NULL) {
TAILQ_FOREACH_SAFE(p, &object->memq, listq, p_next) {
KASSERT(!p->busy && (p->oflags & VPO_BUSY) == 0,
("vm_object_terminate: freeing busy page %p "
"p->busy = %d, p->oflags %x\n", p, p->busy, p->oflags));
("vm_object_terminate: freeing busy page %p", p));
vm_page_lock(p);
/*
* Optimize the page's removal from the object by resetting
* its "object" field. Specifically, if the page is not
* wired, then the effect of this assignment is that
* vm_page_free()'s call to vm_page_remove() will return
* immediately without modifying the page or the object.
*/
p->object = NULL;
if (p->wire_count == 0) {
vm_page_free(p);
PCPU_INC(cnt.v_pfree);
} else
vm_page_remove(p);
}
vm_page_unlock(p);
}
/*
* If the object contained any pages, then reset it to an empty state.
* None of the object's fields, including "resident_page_count", were
* modified by the preceding loop.
*/
if (object->resident_page_count != 0) {
object->root = NULL;
TAILQ_INIT(&object->memq);
object->resident_page_count = 0;
if (object->type == OBJT_VNODE)
vdrop(object->handle);
}
#if VM_NRESERVLEVEL > 0
if (__predict_false(!LIST_EMPTY(&object->rvq)))