From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_MED, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8FBF7C4646D for ; Mon, 13 Aug 2018 17:11:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 16D412189B for ; Mon, 13 Aug 2018 17:11:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=cmpxchg-org.20150623.gappssmtp.com header.i=@cmpxchg-org.20150623.gappssmtp.com header.b="h3ii49Dk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 16D412189B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=cmpxchg.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730093AbeHMTy1 (ORCPT ); Mon, 13 Aug 2018 15:54:27 -0400 Received: from mail-yw1-f67.google.com ([209.85.161.67]:42639 "EHLO mail-yw1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729070AbeHMTy1 (ORCPT ); Mon, 13 Aug 2018 15:54:27 -0400 Received: by mail-yw1-f67.google.com with SMTP id y203-v6so14084804ywd.9 for ; Mon, 13 Aug 2018 10:11:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=d7YjYfmhzgSP6FwYdHeRdy7ygate4wqD0+xYgcOY848=; b=h3ii49DkXCYBxMWjDOjLkNUHcRkxvzX7g8v8B1vR5ncGMn4rx39oY5UI1yGt7q643L KqrAyfgs1dFJpyzwdax15D/unLLJs3CiFfQRXJmYa3c93oAkM1JrPOK2yoLNDlINuKGU na86chzgMKukDlUPQs29PdIE7HcJY5k4cZlyz1MEeTf8TsqnTciOP5kWNdTY0iljAFPd o3BT2Da4lCFEkcdaQyshsf3VTLuVoydqNwQomrnqm3lPjB3PYcIHz53huWekqXDoNwvd 328P9w/zlMpiLumwUZfvsk/Nuqpbeyp9maJj+W4nOTrq8BH27QiUOv8TgdWrwmQCvBk3 HIAQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=d7YjYfmhzgSP6FwYdHeRdy7ygate4wqD0+xYgcOY848=; b=TmA+0qYFI1w//ZgHLud2gX789mePpHKGL8WzwKkwIGLoHpPg6rVwqMxL1Le94qimrz s2+ieVeOXNYMAmsApTh7BBzvzZhA9OX212SuJqUtsGw1sEyrO4Dfrudy+8w2cQfL+pWQ KutaspbtVhJV1eJM3pJYaiGJkitI9spbFxl6IEJHCYfUBwFYWOGXJ+7Bbo21OGx/IyxV WwHFXSmOn3sOvP37wDuO0cEgvEwhRUNnkR56dINKt1KtBDQOmX8M6ubXbU8rf+itVpy9 a3O+syfUcalI9M7ktjfo1DpgQdGyk7zEanJGpjkN9o1RrlWA8pbwqNLgEAWnGL54Rrm0 45wA== X-Gm-Message-State: AOUpUlHc8D9pj8GOe5ItfNLWIF2qzFZ/rtuku0Mry76xnMusgCAC33V3 mupk+U1DnkRYeqGThupI0jLtQw== X-Google-Smtp-Source: AA+uWPx+jIn9KwZMzp44xRXlmyueo4pusE0x8fwJ6bcGhDFK48mI/zvyy+gbySSv45gtxdB0dt9zVA== X-Received: by 2002:a0d:fec2:: with SMTP id o185-v6mr10480546ywf.195.1534180281077; Mon, 13 Aug 2018 10:11:21 -0700 (PDT) Received: from localhost ([2620:10d:c091:200::3:b26f]) by smtp.gmail.com with ESMTPSA id b135-v6sm16319888ywh.24.2018.08.13.10.11.19 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 13 Aug 2018 10:11:20 -0700 (PDT) Date: Mon, 13 Aug 2018 13:11:19 -0400 From: Johannes Weiner To: Tejun Heo Cc: Konstantin Khlebnikov , linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Michal Hocko , Vladimir Davydov , Roman Gushchin Subject: Re: [PATCH RFC 1/3] cgroup: list all subsystem states in debugfs files Message-ID: <20180813171119.GA24658@cmpxchg.org> References: <153414348591.737150.14229960913953276515.stgit@buzz> <20180813134842.GF3978217@devbig004.ftw2.facebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180813134842.GF3978217@devbig004.ftw2.facebook.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 13, 2018 at 06:48:42AM -0700, Tejun Heo wrote: > Hello, Konstantin. > > On Mon, Aug 13, 2018 at 09:58:05AM +0300, Konstantin Khlebnikov wrote: > > After removing cgroup subsystem state could leak or live in background > > forever because it is pinned by some reference. For example memory cgroup > > could be pinned by pages in cache or tmpfs. > > > > This patch adds common debugfs interface for listing basic state for each > > controller. Controller could define callback for dumping own attributes. > > > > In file /sys/kernel/debug/cgroup/ each line shows state in > > format: =... [-- =... ] > > Seems pretty useful to me. Roman, Johannes, what do you guys think? Generally I like the idea of having more introspection into offlined cgroups, but I wonder if having only memory= and swap= could be a little too terse to track down what exactly is pinning the groups. Roman has more experience debugging these pileups, but it seems to me that unless we add a breakdown off memory, and maybe make slabinfo available for these groups, that in practice this might not provide that much more insight than per-cgroup stat counters of dead children.