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authorMateusz Nosek <mateusznosek0@gmail.com>2020-04-01 21:09:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-04-02 09:35:30 -0700
commit736838e964c3282a3472626a97f9f49e020185e0 (patch)
tree91d8ee8f884a79eedce282cc485248090d13ee5f /mm/internal.h
parentee8eb9a5fe86332c6c6163a2322376f960026596 (diff)
mm, pagealloc: micro-optimisation: save two branches on hot page allocation path
This patch makes ALLOC_KSWAPD equal to __GFP_KSWAPD_RECLAIM (cast to int). Thanks to that code like: if (gfp_mask & __GFP_KSWAPD_RECLAIM) alloc_flags |= ALLOC_KSWAPD; can be changed to: alloc_flags |= (__force int) (gfp_mask &__GFP_KSWAPD_RECLAIM); Thanks to this one branch less is generated in the assembly. In case of ALLOC_KSWAPD flag two branches are saved, first one in code that always executes in the beginning of page allocation and the second one in loop in page allocator slowpath. Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Mel Gorman <mgorman@techsingularity.net> Link: http://lkml.kernel.org/r/20200304162118.14784-1-mateusznosek0@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/internal.h')
-rw-r--r--mm/internal.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/internal.h b/mm/internal.h
index 9fb2b8c7928f..129659f1e58a 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -555,7 +555,7 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
#else
#define ALLOC_NOFRAGMENT 0x0
#endif
-#define ALLOC_KSWAPD 0x200 /* allow waking of kswapd */
+#define ALLOC_KSWAPD 0x800 /* allow waking of kswapd, __GFP_KSWAPD_RECLAIM set */
enum ttu_flags;
struct tlbflush_unmap_batch;