The patch titled
Subject: mm, page_alloc: use unlikely() in task_capc()
has been added to the -mm tree. Its filename is
mm-page_alloc-use-unlikely-in-task_capc.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-use-unlikely-in-task_capc.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-use-unlikely-in-task_capc.patch
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------------------------------------------------------
From: Vlastimil Babka <vbabka@xxxxxxx>
Subject: mm, page_alloc: use unlikely() in task_capc()
Hugh noted that task_capc() could use unlikely(), as most of the time
there is no capture in progress and we are in page freeing hot path.
Indeed adding unlikely() produces assembly that better matches the
assumption and moves all the tests away from the hot path.
I have also noticed that we don't need to test for cc->direct_compaction
as the only place we set current->task_capture is compact_zone_order()
which also always sets cc->direct_compaction true.
Link: http://lkml.kernel.org/r/4a24f7af-3aa5-6e80-4ae6-8f253b562039@xxxxxxx
Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
Suggested-by: Hugh Dickins <hughd@xxxxxxxxxx>
Acked-by: Hugh Dickins <hughd@googlecom>
Cc: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Cc: Li Wang <liwang@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
--- a/mm/page_alloc.c~mm-page_alloc-use-unlikely-in-task_capc
+++ a/mm/page_alloc.c
@@ -813,11 +813,10 @@ static inline struct capture_control *ta
{
struct capture_control *capc = current->capture_control;
- return capc &&
+ return unlikely(capc) &&
!(current->flags & PF_KTHREAD) &&
!capc->page &&
- capc->cc->zone == zone &&
- capc->cc->direct_compaction ? capc : NULL;
+ capc->cc->zone == zone ? capc : NULL;
}
static inline bool
_
Patches currently in -mm which might be from vbabka@xxxxxxx are
mm-compaction-make-capture-control-handling-safe-wrt-interrupts.patch
mm-page_alloc-use-unlikely-in-task_capc.patch
mm-slub-extend-slub_debug-syntax-for-multiple-blocks.patch
mm-slub-make-some-slub_debug-related-attributes-read-only.patch
mm-slub-remove-runtime-allocation-order-changes.patch
mm-slub-make-remaining-slub_debug-related-attributes-read-only.patch
mm-slub-make-reclaim_account-attribute-read-only.patch
mm-slub-introduce-static-key-for-slub_debug.patch
mm-slub-introduce-kmem_cache_debug_flags.patch
mm-slub-extend-checks-guarded-by-slub_debug-static-key.patch
mm-slab-slub-move-and-improve-cache_from_obj.patch
