From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id 6D13A6B0005 for ; Fri, 27 Apr 2018 05:17:07 -0400 (EDT) Received: by mail-wr0-f198.google.com with SMTP id u13-v6so820576wre.1 for ; Fri, 27 Apr 2018 02:17:07 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id g53-v6si1337186edb.149.2018.04.27.02.17.04 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 27 Apr 2018 02:17:04 -0700 (PDT) Subject: Re: [PATCH] mm: don't show nr_indirectly_reclaimable in /proc/vmstat References: <20180425191422.9159-1-guro@fb.com> <20180426200331.GZ17484@dhcp22.suse.cz> From: Vlastimil Babka Message-ID: <99208563-1171-b7e7-a0d7-b47b6c5e2307@suse.cz> Date: Fri, 27 Apr 2018 11:17:01 +0200 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes , Michal Hocko Cc: Roman Gushchin , 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 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).