The patch titled
mm: unlockless reclaim
has been added to the -mm tree. Its filename is
mm-unlockless-reclaim.patch
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: mm: unlockless reclaim
From: Nick Piggin <npiggin@xxxxxxx>
unlock_page is fairly expensive. It can be avoided in page reclaim
success path. By definition if we have any other references to the page
it would be a bug anyway.
Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff -puN mm/vmscan.c~mm-unlockless-reclaim mm/vmscan.c
--- a/mm/vmscan.c~mm-unlockless-reclaim
+++ a/mm/vmscan.c
@@ -781,7 +781,14 @@ static unsigned long shrink_page_list(st
if (!mapping || !__remove_mapping(mapping, page))
goto keep_locked;
- unlock_page(page);
+ /*
+ * At this point, we have no other references and there is
+ * no way to pick any more up (removed from LRU, removed
+ * from pagecache). Can use non-atomic bitops now (and
+ * we obviously don't have to worry about waking up a process
+ * waiting on the page lock, because there are no references.
+ */
+ __clear_page_locked(page);
free_it:
nr_reclaimed++;
if (!pagevec_add(&freed_pvec, page)) {
_
Patches currently in -mm which might be from npiggin@xxxxxxx are
origin.patch
linux-next.patch
mm-dirty-page-tracking-race-fix.patch
mm-dirty-page-tracking-race-fix-fix.patch
mm-xip-fix-fault-vs-sparse-page-invalidate-race.patch
mm-xip-ext2-fix-block-allocation-race.patch
vmscan-move-isolate_lru_page-to-vmscanc.patch
mlock-mlocked-pages-are-unevictable.patch
mmap-handle-mlocked-pages-during-map-remap-unmap.patch
vmstat-mlocked-pages-statistics.patch
mm-pagecache-insertion-fewer-atomics.patch
mm-unlockless-reclaim.patch
mm-page-lock-use-lock-bitops.patch
fs-buffer-lock-use-lock-bitops.patch
mm-page-allocator-minor-speedup.patch
reiser4.patch
likeliness-accounting-change-and-cleanup.patch
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