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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 BCD94C388F7 for ; Tue, 3 Nov 2020 13:22:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6EA902071E for ; Tue, 3 Nov 2020 13:22:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="Pxo79IfA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729204AbgKCNWY (ORCPT ); Tue, 3 Nov 2020 08:22:24 -0500 Received: from mx2.suse.de ([195.135.220.15]:56308 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729078AbgKCNWX (ORCPT ); Tue, 3 Nov 2020 08:22:23 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1604409742; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=VeA9Qsqxu1/i14CMSGPPmW3KXKC7b+HEm7qKKl5XDvg=; b=Pxo79IfAbvAKkRNNFMbGkHgZWU7zirElkyhd/EpedIl5/ACqkBp91t0MQK0Gwnhw0iiO/G zK20Exyj3tPnz68nn91WwrEvThhmjjygMxsW7/Mzw82amVnPx/GxV7zJaHowJCDqpugz9m IbwhDG6IGCbT463rGcyFKbt3U2zSqXQ= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id DF85DAB0E; Tue, 3 Nov 2020 13:22:21 +0000 (UTC) Date: Tue, 3 Nov 2020 14:22:21 +0100 From: Michal Hocko To: Roman Gushchin Cc: Johannes Weiner , Michal =?iso-8859-1?Q?Koutn=FD?= , Richard Palethorpe , ltp@lists.linux.it, Andrew Morton , Shakeel Butt , Christoph Lameter , Tejun Heo , Vlastimil Babka , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] mm: memcg/slab: Stop reparented obj_cgroups from charging root Message-ID: <20201103132221.GI21990@dhcp22.suse.cz> References: <20201014190749.24607-1-rpalethorpe@suse.com> <20201016094702.GA95052@blackbook> <20201016145308.GA312010@cmpxchg.org> <20201016171502.GA102311@blackbook> <20201019222845.GA64774@carbon.dhcp.thefacebook.com> <20201020162714.GC46039@blackbook> <20201020170717.GA153102@carbon.DHCP.thefacebook.com> <20201020181822.GA397401@cmpxchg.org> <20201021193322.GA300658@carbon.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201021193322.GA300658@carbon.dhcp.thefacebook.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I am sorry but I was quite busy at the time this has been discussed. Now that I got to this thread finally I am wondering whether this resp. other root cgroup exceptions have any follow up. I have seen the issue is fixed in Linus tree by 8de15e920dc8 ("mm: memcg: link page counters to root if use_hierarchy is false"). Thanks for taking care of that! I do agree that this approach is the most reasonable immediate fix. Btw. we have been carrying a warning about non hierarchical hierarchies for years in our distribution kernels and haven't heard of any actual bug reports (except for LTP driven ones). So we might be really close to simply drop this functionality completely. This would simplify the code and prevent from future surprises. Thanks! -- Michal Hocko SUSE Labs