From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751504AbcFNGgS (ORCPT ); Tue, 14 Jun 2016 02:36:18 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:34685 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751039AbcFNGgQ (ORCPT ); Tue, 14 Jun 2016 02:36:16 -0400 Date: Tue, 14 Jun 2016 08:36:08 +0200 From: Michal Hocko To: Mel Gorman Cc: Andrew Morton , Marcin Wojtas , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vlastimil Babka Subject: Re: [PATCH] mm, slaub: Add __GFP_ATOMIC to the GFP reclaim mask Message-ID: <20160614063608.GA5681@dhcp22.suse.cz> References: <20160610093832.GK2527@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160610093832.GK2527@techsingularity.net> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 10-06-16 10:38:32, Mel Gorman wrote: > 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 Acked-by: Michal Hocko > --- > 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)) > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org -- Michal Hocko SUSE Labs