Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 08/68] mm, sl[au]b: add __GFP_ATOMIC to the GFP reclaim mask | Date | Mon, 8 Aug 2016 21:10:43 +0200 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Mel Gorman <mgorman@techsingularity.net>
commit e838a45f9392a5bd2be1cd3ab0b16ae85857461c upstream.
Commit d0164adc89f6 ("mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd") modified __GFP_WAIT to explicitly identify the difference between atomic callers and those that were unwilling to sleep. Later the definition was removed entirely.
The GFP_RECLAIM_MASK is the set of flags that affect watermark checking and reclaim behaviour but __GFP_ATOMIC was never added. Without it, atomic users of the slab allocator strip the __GFP_ATOMIC flag and cannot access the page allocator atomic reserves. This patch addresses the problem.
The user-visible impact depends on the workload but potentially atomic allocations unnecessarily fail without this path.
Link: http://lkml.kernel.org/r/20160610093832.GK2527@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reported-by: Marcin Wojtas <mw@semihalf.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- mm/internal.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/mm/internal.h +++ b/mm/internal.h @@ -22,7 +22,8 @@ */ #define GFP_RECLAIM_MASK (__GFP_RECLAIM|__GFP_HIGH|__GFP_IO|__GFP_FS|\ __GFP_NOWARN|__GFP_REPEAT|__GFP_NOFAIL|\ - __GFP_NORETRY|__GFP_MEMALLOC|__GFP_NOMEMALLOC) + __GFP_NORETRY|__GFP_MEMALLOC|__GFP_NOMEMALLOC|\ + __GFP_ATOMIC) /* The GFP flags allowed during early boot */ #define GFP_BOOT_MASK (__GFP_BITS_MASK & ~(__GFP_RECLAIM|__GFP_IO|__GFP_FS))
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