From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f197.google.com (mail-qk0-f197.google.com [209.85.220.197]) by kanga.kvack.org (Postfix) with ESMTP id 087AA6B0005 for ; Fri, 27 Apr 2018 06:56:46 -0400 (EDT) Received: by mail-qk0-f197.google.com with SMTP id c73so1065419qke.2 for ; Fri, 27 Apr 2018 03:56:46 -0700 (PDT) Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com. [67.231.145.42]) by mx.google.com with ESMTPS id c6-v6si1040536qtg.258.2018.04.27.03.56.43 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 27 Apr 2018 03:56:44 -0700 (PDT) Date: Fri, 27 Apr 2018 11:55:54 +0100 From: Roman Gushchin Subject: Re: [PATCH] mm: don't show nr_indirectly_reclaimable in /proc/vmstat Message-ID: <20180427105549.GA8127@castle.DHCP.thefacebook.com> References: <20180425191422.9159-1-guro@fb.com> <20180426200331.GZ17484@dhcp22.suse.cz> <99208563-1171-b7e7-a0d7-b47b6c5e2307@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <99208563-1171-b7e7-a0d7-b47b6c5e2307@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka Cc: David Rientjes , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, kernel-team@fb.com, Matthew Wilcox , Andrew Morton , Alexander Viro , Johannes Weiner On Fri, Apr 27, 2018 at 11:17:01AM +0200, Vlastimil Babka wrote: > On 04/26/2018 11:55 PM, David Rientjes wrote: > > On Thu, 26 Apr 2018, Michal Hocko wrote: > > > >>> Don't show nr_indirectly_reclaimable in /proc/vmstat, > >>> because there is no need in exporting this vm counter > >>> to the userspace, and some changes are expected > >>> in reclaimable object accounting, which can alter > >>> this counter. > >>> > >>> Signed-off-by: Roman Gushchin > >>> Cc: Vlastimil Babka > >>> Cc: Matthew Wilcox > >>> Cc: Andrew Morton > >>> Cc: Alexander Viro > >>> Cc: Michal Hocko > >>> Cc: Johannes Weiner > >> > >> This is quite a hack. I would much rather revert the counter and fixed > >> it the way Vlastimil has proposed. But if there is a strong opposition > >> to the revert then this is probably the simples thing to do. Therefore > >> > > > > Implementing this counter as a vmstat doesn't make much sense based on how > > it's used. Do you have a link to what Vlastimil proposed? I haven't seen > > mention of alternative ideas. > > It was in the original thread, see e.g. > <08524819-14ef-81d0-fa90-d7af13c6b9d5@suse.cz> > > However it will take some time to get that in mainline, and meanwhile > the current implementation does prevent a DOS. So I doubt it can be > fully reverted - as a compromise I just didn't want the counter to > become ABI. TBH though, other people at LSF/MM didn't seem concerned > that /proc/vmstat is an ABI that we can't change (i.e. counters have > been presumably removed in the past already). > Thank you, Vlastimil! That pretty much matches my understanding of the case. BTW, are you planning to work on supporting reclaimable objects by slab allocators? Thanks!