From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f69.google.com (mail-pg0-f69.google.com [74.125.83.69]) by kanga.kvack.org (Postfix) with ESMTP id 176D06B0261 for ; Thu, 23 Nov 2017 05:02:22 -0500 (EST) Received: by mail-pg0-f69.google.com with SMTP id s18so18591445pge.19 for ; Thu, 23 Nov 2017 02:02:22 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id e29si15326993pgn.215.2017.11.23.02.02.20 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 23 Nov 2017 02:02:20 -0800 (PST) Date: Thu, 23 Nov 2017 11:02:18 +0100 From: Michal Hocko Subject: Re: [PATCH] mm,vmscan: Mark register_shrinker() as __must_check Message-ID: <20171123100218.vf4zc47pmy3f67ey@dhcp22.suse.cz> References: <201711220709.JJJ12483.MtFOOJFHOLQSVF@I-love.SAKURA.ne.jp> <201711221953.IDJ12440.OQLtFVOJFMSHFO@I-love.SAKURA.ne.jp> <20171122203907.GI4094@dastard> <201711231534.BBI34381.tJOOHLQMOFVFSF@I-love.SAKURA.ne.jp> <2178e42e-9600-4f9a-4b91-22d2ba6f98c0@redhat.com> <201711231856.CFH69777.FtOSJFMQHLOVFO@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201711231856.CFH69777.FtOSJFMQHLOVFO@I-love.SAKURA.ne.jp> Sender: owner-linux-mm@kvack.org List-ID: To: Tetsuo Handa Cc: pbonzini@redhat.com, david@fromorbit.com, akpm@linux-foundation.org, glauber@scylladb.com, linux-mm@kvack.org, viro@zeniv.linux.org.uk, jack@suse.com, airlied@linux.ie, alexander.deucher@amd.com, shli@fb.com, snitzer@redhat.com On Thu 23-11-17 18:56:53, Tetsuo Handa wrote: > Paolo Bonzini wrote: > > On 23/11/2017 07:34, Tetsuo Handa wrote: > > >> Just fix the numa aware shrinkers, as they are the only ones that > > >> will have this problem. There are only 6 of them, and only the 3 > > >> that existed at the time that register_shrinker() was changed to > > >> return an error fail to check for an error. i.e. the superblock > > >> shrinker, the XFS dquot shrinker and the XFS buffer cache shrinker. > > > > > > You are assuming the "too small to fail" memory-allocation rule > > > by ignoring that this problem is caused by fault injection. > > > > Fault injection should also obey the too small to fail rule, at least by > > default. > > > > Pardon? Most allocation requests in the kernel are <= 32KB. > Such change makes fault injection useless. ;-) Agreed! All we need is to fix the shrinker registration callers. It is that simple. The rest is just a distraction. -- Michal Hocko SUSE Labs -- 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