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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				| @ -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; | ||||
|  | ||||
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