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Change vm_object_madvise() so that it checks whether the page is invalid

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or unmanaged before acquiring the page queues lock.  Neither of these
tests require that lock.  Moreover, a better way of testing if the page
is unmanaged is to test the type of vm object.  This avoids a pointless
vm_page_lookup().

MFC after:	3 weeks
This commit is contained in:
alc 2010-04-28 04:57:32 +00:00
parent ab8f1a2302
commit e3ebeca68e
1 changed files with 6 additions and 10 deletions
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16
sys/vm/vm_object.c
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@ -1162,7 +1162,8 @@ shadowlookup:
(tobject->flags & OBJ_ONEMAPPING) == 0) {
goto unlock_tobject;
}
}
} else if (tobject->type == OBJT_PHYS)
goto unlock_tobject;
m = vm_page_lookup(tobject, tpindex);
if (m == NULL && advise == MADV_WILLNEED) {
/*
@ -1189,18 +1190,13 @@ shadowlookup:
VM_OBJECT_UNLOCK(tobject);
tobject = backing_object;
goto shadowlookup;
}
} else if (m->valid != VM_PAGE_BITS_ALL)
goto unlock_tobject;
/*
* If the page is busy or not in a normal active state,
* we skip it. If the page is not managed there are no
* page queues to mess with. Things can break if we mess
* with pages in any of the below states.
* If the page is not in a normal state, skip it.
*/
vm_page_lock_queues();
if (m->hold_count ||
m->wire_count ||
(m->flags & PG_UNMANAGED) ||
m->valid != VM_PAGE_BITS_ALL) {
if (m->hold_count != 0 || m->wire_count != 0) {
vm_page_unlock_queues();
goto unlock_tobject;
}