Author: alc
Date: Sun Feb 9 01:59:52 2014
New Revision: 261647
URL: http://svnweb.freebsd.org/changeset/base/261647
Log:
Don't call vm_fault_prefault() on zero-fill faults. It's a waste of time.
Successful prefaults after a zero-fill fault are extremely rare.
Modified:
head/sys/vm/vm_fault.c
Modified: head/sys/vm/vm_fault.c
==============================================================================
--- head/sys/vm/vm_fault.c Sun Feb 9 01:21:30 2014 (r261646)
+++ head/sys/vm/vm_fault.c Sun Feb 9 01:59:52 2014 (r261647)
@@ -652,6 +652,8 @@ vnode_locked:
}
PCPU_INC(cnt.v_zfod);
fs.m->valid = VM_PAGE_BITS_ALL;
+ /* Don't try to prefault neighboring pages. */
+ faultcount = 1;
break; /* break to PAGE HAS BEEN FOUND */
} else {
KASSERT(fs.object != next_object,
@@ -897,7 +899,8 @@ vnode_locked:
* won't find it (yet).
*/
pmap_enter(fs.map->pmap, vaddr, fault_type, fs.m, prot, wired);
- if ((fault_flags & VM_FAULT_CHANGE_WIRING) == 0 && wired == 0)
+ if (faultcount != 1 && (fault_flags & VM_FAULT_CHANGE_WIRING) == 0 &&
+ wired == 0)
vm_fault_prefault(&fs, vaddr, faultcount, reqpage);
VM_OBJECT_WLOCK(fs.object);
vm_page_lock(fs.m);
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