From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f71.google.com (mail-it0-f71.google.com [209.85.214.71]) by kanga.kvack.org (Postfix) with ESMTP id 3A6C26B038E for ; Tue, 7 Mar 2017 12:05:33 -0500 (EST) Received: by mail-it0-f71.google.com with SMTP id 14so9039505itw.3 for ; Tue, 07 Mar 2017 09:05:33 -0800 (PST) Received: from aserp1040.oracle.com (aserp1040.oracle.com. [141.146.126.69]) by mx.google.com with ESMTPS id p5si1006565iod.111.2017.03.07.09.05.31 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 07 Mar 2017 09:05:32 -0800 (PST) Date: Tue, 7 Mar 2017 09:05:19 -0800 From: "Darrick J. Wong" Subject: Re: [RFC PATCH 3/4] xfs: map KM_MAYFAIL to __GFP_RETRY_MAYFAIL Message-ID: <20170307170519.GE5281@birch.djwong.org> References: <20170307154843.32516-1-mhocko@kernel.org> <20170307154843.32516-4-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170307154843.32516-4-mhocko@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: linux-mm@kvack.org, Vlastimil Babka , Johannes Weiner , Mel Gorman , Andrew Morton , LKML , Michal Hocko On Tue, Mar 07, 2017 at 04:48:42PM +0100, 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. > > Cc: Darrick J. Wong > 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 ae08cfd9552a..ac80a4855c83 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 for ever for all s/for ever/forever/ > + * request sizes. > + */ > + if (flags & KM_MAYFAIL) > + lflags |= __GFP_RETRY_MAYFAIL; But otherwise seems ok from a quick grep -B5 MAYFAIL through the XFS code. (Has this been tested anywhere?) --D > + > if (flags & KM_ZERO) > lflags |= __GFP_ZERO; > > -- > 2.11.0 > -- 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