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authorRobin Holt <holt@sgi.com>2010-03-23 13:35:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-03-24 16:31:20 -0700
commitcb53237513bd1e090cce120efe12ede72c932b5f (patch)
tree43d0665b57b654cf10ea12233e8234367e1634e0 /mm
parent20072205fcdf7d85cd3101f1f11dfab333c5fd0c (diff)
downloadconfigs-cb53237513bd1e090cce120efe12ede72c932b5f.tar.gz
mm/ksm.c is doing an unneeded _notify in write_protect_page.
ksm.c's write_protect_page implements a lockless means of verifying a page does not have any users of the page which are not accounted for via other kernel tracking means. It does this by removing the writable pte with TLB flushes, checking the page_count against the total known users, and then using set_pte_at_notify to make it a read-only entry. An unneeded mmu_notifier callout is made in the case where the known users does not match the page_count. In that event, we are inserting the identical pte and there is no need for the set_pte_at_notify, but rather the simpler set_pte_at suffices. Signed-off-by: Robin Holt <holt@sgi.com> Acked-by: Izik Eidus <ieidus@redhat.com> Acked-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Chris Wright <chrisw@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/ksm.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/ksm.c b/mm/ksm.c
index a93f1b7f508..8cdfc2a1e8b 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -751,7 +751,7 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
* page
*/
if (page_mapcount(page) + 1 + swapped != page_count(page)) {
- set_pte_at_notify(mm, addr, ptep, entry);
+ set_pte_at(mm, addr, ptep, entry);
goto out_unlock;
}
entry = pte_wrprotect(entry);