From a56f57ff94c25d5d80def06f3ed8fe7f99147762 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 16 Jun 2009 15:32:02 -0700 Subject: [PATCH] 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 Reviewed-by: Pekka Enberg Reviewed-by: KOSAKI Motohiro Cc: Christoph Lameter Cc: Peter Zijlstra Cc: Nick Piggin Cc: Dave Hansen Cc: Lee Schermerhorn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 6 ++++-- 1 file 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; -- 2.20.1