From 4167e9b2cf10f8a4bcda0c713ddc8bb0a18e8187 Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Tue, 14 Apr 2015 15:46:55 -0700 Subject: mm: remove GFP_THISNODE NOTE: this is not about __GFP_THISNODE, this is only about GFP_THISNODE. GFP_THISNODE is a secret combination of gfp bits that have different behavior than expected. It is a combination of __GFP_THISNODE, __GFP_NORETRY, and __GFP_NOWARN and is special-cased in the page allocator slowpath to fail without trying reclaim even though it may be used in combination with __GFP_WAIT. An example of the problem this creates: commit e97ca8e5b864 ("mm: fix GFP_THISNODE callers and clarify") fixed up many users of GFP_THISNODE that really just wanted __GFP_THISNODE. The problem doesn't end there, however, because even it was a no-op for alloc_misplaced_dst_page(), which also sets __GFP_NORETRY and __GFP_NOWARN, and migrate_misplaced_transhuge_page(), where __GFP_NORETRY and __GFP_NOWAIT is set in GFP_TRANSHUGE. Converting GFP_THISNODE to __GFP_THISNODE is a no-op in these cases since the page allocator special-cases __GFP_THISNODE && __GFP_NORETRY && __GFP_NOWARN. It's time to just remove GFP_THISNODE entirely. We leave __GFP_THISNODE to restrict an allocation to a local node, but remove GFP_THISNODE and its obscurity. Instead, we require that a caller clear __GFP_WAIT if it wants to avoid reclaim. This allows the aforementioned functions to actually reclaim as they should. It also enables any future callers that want to do __GFP_THISNODE but also __GFP_NORETRY && __GFP_NOWARN to reclaim. The rule is simple: if you don't want to reclaim, then don't set __GFP_WAIT. Aside: ovs_flow_stats_update() really wants to avoid reclaim as well, so it is unchanged. Signed-off-by: David Rientjes Acked-by: Vlastimil Babka Cc: Christoph Lameter Acked-by: Pekka Enberg Cc: Joonsoo Kim Acked-by: Johannes Weiner Cc: Mel Gorman Cc: Pravin Shelar Cc: Jarno Rajahalme Cc: Li Zefan Cc: Greg Thelen Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/gfp.h | 10 ---------- 1 file changed, 10 deletions(-) (limited to 'include/linux/gfp.h') diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 51bd1e72a917..4423a0f8eabe 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -117,16 +117,6 @@ struct vm_area_struct; __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN | \ __GFP_NO_KSWAPD) -/* - * GFP_THISNODE does not perform any reclaim, you most likely want to - * use __GFP_THISNODE to allocate from a given node without fallback! - */ -#ifdef CONFIG_NUMA -#define GFP_THISNODE (__GFP_THISNODE | __GFP_NOWARN | __GFP_NORETRY) -#else -#define GFP_THISNODE ((__force gfp_t)0) -#endif - /* This mask makes up all the page movable related flags */ #define GFP_MOVABLE_MASK (__GFP_RECLAIMABLE|__GFP_MOVABLE) -- cgit v1.2.3