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>
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1 changed files with 4 additions and 2 deletions
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@ -1616,14 +1616,16 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
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int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
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const gfp_t wait = gfp_mask & __GFP_WAIT;
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/* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
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BUILD_BUG_ON(__GFP_HIGH != ALLOC_HIGH);
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/*
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* The caller may dip into page reserves a bit more if the caller
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* cannot run direct reclaim, or if the caller has realtime scheduling
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* policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
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* set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
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*/
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if (gfp_mask & __GFP_HIGH)
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alloc_flags |= ALLOC_HIGH;
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alloc_flags |= (gfp_mask & __GFP_HIGH);
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if (!wait) {
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alloc_flags |= ALLOC_HARDER;
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