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[209.85.220.65]) by mx.google.com with SMTPS id e138sor543890ywa.30.2019.06.19.08.35.59 for (Google Transport Security); Wed, 19 Jun 2019 08:35:59 -0700 (PDT) Received-SPF: pass (google.com: domain of shakeelb@google.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b="shPcVD/R"; spf=pass (google.com: domain of shakeelb@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=shakeelb@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dwSXE2HJvCidsxfi3LfOlPWV76WiyrJo+zGle1/Posk=; b=shPcVD/RnA32q5R954zhbHbCNmUv9WV3y1RqIyqvsdpscKxDrx898pdEDLhp5LN0to DbXYXu+gvach7KLfWm2FSbsVhYhvyvmXGjhENsRkiMKSnzsr2EcXvlHfynmEaSSmHkie 5Yts8FyiwXSFtBQH6RFnmuWPot9WB3/pECxotkeyoOEWY/zSS12ndpAUC0/eRSSv0R9U yZ3R5iGCjfEkm/U8Cqn+k5IXrPvpygVj1VJXilucmRW00bBqpvtpm69ynGQS7hLw53mK vTA414ToCI8UTtvUA421mNTNbwrVbYtIQ7ja94Ya4nfK98Lsk+qkHykltGKqlw+41fs5 JPBQ== X-Google-Smtp-Source: APXvYqxkP5tURjFEv1pLRgOMle49c6W6qB/eYRu2b+HirEU7vb0z2HAUJr63bUo2XJQhzwumW474OnOIqm7cAPB2g2Y= X-Received: by 2002:a81:3a0f:: with SMTP id h15mr70130882ywa.34.1560958558977; Wed, 19 Jun 2019 08:35:58 -0700 (PDT) MIME-Version: 1.0 References: <20190619144610.12520-1-longman@redhat.com> <20831975-590f-ecab-53db-5d7e6b1a053f@redhat.com> In-Reply-To: <20831975-590f-ecab-53db-5d7e6b1a053f@redhat.com> From: Shakeel Butt Date: Wed, 19 Jun 2019 08:35:47 -0700 Message-ID: Subject: Re: [PATCH] mm, memcg: Add a memcg_slabinfo debugfs file To: Waiman Long Cc: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Linux MM , LKML , Michal Hocko , Roman Gushchin , Johannes Weiner , Vladimir Davydov Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Jun 19, 2019 at 8:30 AM Waiman Long wrote: > > On 6/19/19 11:18 AM, Shakeel Butt wrote: > > On Wed, Jun 19, 2019 at 7:46 AM Waiman Long wrote: > >> There are concerns about memory leaks from extensive use of memory > >> cgroups as each memory cgroup creates its own set of kmem caches. There > >> is a possiblity that the memcg kmem caches may remain even after the > >> memory cgroup removal. Therefore, it will be useful to show how many > >> memcg caches are present for each of the kmem caches. > >> > >> This patch introduces a new /memcg_slabinfo file which is > >> somewhat similar to /proc/slabinfo in format, but lists only slabs that > >> are in memcg kmem caches. Information available in /proc/slabinfo are > >> not repeated in memcg_slabinfo. > >> > > At Google, we have an interface /proc/slabinfo_full which shows each > > kmem cache (root and memcg) on a separate line i.e. no accumulation. > > This interface has helped us a lot for debugging zombies and memory > > leaks. The name of the memcg kmem caches include the memcg name, css > > id and "dead" for offlined memcgs. I think these extra information is > > much more useful for debugging. What do you think? > > > > Shakeel > > Yes, I think that can be a good idea. My only concern is that it can be > very verbose. Will work on a v2 patch. > Yes, it is very verbose but it is only for debugging and normal users should not be (continuously) reading that interface. Shakeel