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| author | Mel Gorman <mel@csn.ul.ie> | 2009-06-16 15:32:02 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-16 19:47:33 -0700 |
| commit | a56f57ff94c25d5d80def06f3ed8fe7f99147762 (patch) | |
| tree | 13cb2626a969e381cb5e3d6ba7f614b9d5ef7a42 /mm/page_alloc.c | |
| parent | 341ce06f69abfafa31b9468410a13dbd60e2b237 (diff) | |
| download | lwn-a56f57ff94c25d5d80def06f3ed8fe7f99147762.tar.gz lwn-a56f57ff94c25d5d80def06f3ed8fe7f99147762.zip | |
page allocator: remove a branch by assuming __GFP_HIGH == ALLOC_HIGH
Allocations that specify __GFP_HIGH get the ALLOC_HIGH flag. If these
flags are equal to each other, we can eliminate a branch.
[akpm@linux-foundation.org: Suggested the hack]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
| -rw-r--r-- | mm/page_alloc.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index ef870fb92f74..94f33e2b7f0b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1616,14 +1616,16 @@ gfp_to_alloc_flags(gfp_t gfp_mask) int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET; const gfp_t wait = gfp_mask & __GFP_WAIT; + /* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */ + BUILD_BUG_ON(__GFP_HIGH != ALLOC_HIGH); + /* * The caller may dip into page reserves a bit more if the caller * cannot run direct reclaim, or if the caller has realtime scheduling * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH). */ - if (gfp_mask & __GFP_HIGH) - alloc_flags |= ALLOC_HIGH; + alloc_flags |= (gfp_mask & __GFP_HIGH); if (!wait) { alloc_flags |= ALLOC_HARDER; |