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| author |   Mateusz Nosek <mateusznosek0@gmail.com> | 2020-04-01 21:09:47 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2020-04-02 09:35:30 -0700 |
| commit | 736838e964c3282a3472626a97f9f49e020185e0 (patch) | |
| tree | 91d8ee8f884a79eedce282cc485248090d13ee5f /mm/internal.h | |
| parent | mm/page_alloc: increase default min_free_kbytes bound (diff) | |
| download | wireguard-linux-736838e964c3282a3472626a97f9f49e020185e0.tar.xz wireguard-linux-736838e964c3282a3472626a97f9f49e020185e0.zip | |
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.h | 2 |
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; |