From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932233AbcFJJii (ORCPT ); Fri, 10 Jun 2016 05:38:38 -0400 Received: from outbound-smtp08.blacknight.com ([46.22.139.13]:59470 "EHLO outbound-smtp08.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751060AbcFJJig (ORCPT ); Fri, 10 Jun 2016 05:38:36 -0400 Date: Fri, 10 Jun 2016 10:38:32 +0100 From: Mel Gorman To: Andrew Morton Cc: Marcin Wojtas , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vlastimil Babka Subject: [PATCH] mm, slaub: Add __GFP_ATOMIC to the GFP reclaim mask Message-ID: <20160610093832.GK2527@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Cc: # 4.4+ Reported-by: Marcin Wojtas Signed-off-by: Mel Gorman --- mm/internal.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/internal.h b/mm/internal.h index a37e5b6f9d25..2524ec880e24 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -24,7 +24,8 @@ */ #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))