From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752609AbdF0Ivd (ORCPT ); Tue, 27 Jun 2017 04:51:33 -0400 Received: from mx2.suse.de ([195.135.220.15]:46012 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752603AbdF0It7 (ORCPT ); Tue, 27 Jun 2017 04:49:59 -0400 Date: Tue, 27 Jun 2017 10:49:50 +0200 From: Michal Hocko To: Andrew Morton Cc: Vlastimil Babka , Johannes Weiner , Mel Gorman , NeilBrown , LKML , linux-mm@kvack.org, Christoph Hellwig , "Darrick J. Wong" Subject: Re: [PATCH 3/6] xfs: map KM_MAYFAIL to __GFP_RETRY_MAYFAIL Message-ID: <20170627084950.GI28072@dhcp22.suse.cz> References: <20170623085345.11304-1-mhocko@kernel.org> <20170623085345.11304-4-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170623085345.11304-4-mhocko@kernel.org> 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 Christoph, Darrick could you have a look at this patch please? Andrew has put it into mmotm but I definitely do not want it passes your attention. On Fri 23-06-17 10:53:42, Michal Hocko wrote: > From: Michal Hocko > > KM_MAYFAIL didn't have any suitable GFP_FOO counterpart until recently > so it relied on the default page allocator behavior for the given set > of flags. This means that small allocations actually never failed. > > Now that we have __GFP_RETRY_MAYFAIL flag which works independently on the > allocation request size we can map KM_MAYFAIL to it. The allocator will > try as hard as it can to fulfill the request but fails eventually if > the progress cannot be made. It does so without triggering the OOM > killer which can be seen as an improvement because KM_MAYFAIL users > should be able to deal with allocation failures. > > Cc: Darrick J. Wong > Cc: Christoph Hellwig > Signed-off-by: Michal Hocko > --- > fs/xfs/kmem.h | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/fs/xfs/kmem.h b/fs/xfs/kmem.h > index d6ea520162b2..4d85992d75b2 100644 > --- a/fs/xfs/kmem.h > +++ b/fs/xfs/kmem.h > @@ -54,6 +54,16 @@ kmem_flags_convert(xfs_km_flags_t flags) > lflags &= ~__GFP_FS; > } > > + /* > + * Default page/slab allocator behavior is to retry for ever > + * for small allocations. We can override this behavior by using > + * __GFP_RETRY_MAYFAIL which will tell the allocator to retry as long > + * as it is feasible but rather fail than retry forever for all > + * request sizes. > + */ > + if (flags & KM_MAYFAIL) > + lflags |= __GFP_RETRY_MAYFAIL; > + > if (flags & KM_ZERO) > lflags |= __GFP_ZERO; > > -- > 2.11.0 > -- Michal Hocko SUSE Labs