+ mm-page_alloc-use-unlikely-in-task_capc.patch added to -mm tree

+ mm-page_alloc-use-unlikely-in-task_capc.patch added to -mm tree

[akpm]

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@suse.cz>
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@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Suggested-by: Hugh Dickins <hughd@google.com>
Acked-by: Hugh Dickins <hughd@googlecom>
Cc: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Li Wang <liwang@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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@suse.cz 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