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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A800DC433FE for ; Tue, 10 May 2022 13:36:39 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DBB6A6B0071; Tue, 10 May 2022 09:36:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D44A76B0073; Tue, 10 May 2022 09:36:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BE67E6B0074; Tue, 10 May 2022 09:36:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id A949F6B0071 for ; Tue, 10 May 2022 09:36:38 -0400 (EDT) Received: from smtpin31.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 8895721A16 for ; Tue, 10 May 2022 13:36:38 +0000 (UTC) X-FDA: 79449933276.31.7A9FFBE Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf29.hostedemail.com (Postfix) with ESMTP id 414E01200B6 for ; Tue, 10 May 2022 13:36:31 +0000 (UTC) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 9D9371F8BB; Tue, 10 May 2022 13:36:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1652189796; h=from:from:reply-to: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=p4sKAZLovajkwQg62mRgYfSfMqbrhePxszIN411IYQg=; b=tovm3tZ+1QWr/SxV5JtdrWCNJ7FQX0r5/3bS75ATrIpgw5RXo0a2u28xBsFvvpqOMkw7UT +TrRpOhjh0GVX+9CJ46QGv+Xzz2tg2x+Ugu5wzM0kN6Q/YM7fsthLicCDxDtyAZjvpX6VN 1SJ6PdLrZJwEQhuF+4IMU3OxodHogj8= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id CDCAB2C141; Tue, 10 May 2022 13:36:35 +0000 (UTC) Date: Tue, 10 May 2022 15:36:34 +0200 From: Michal Hocko To: CGEL Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, willy@infradead.org, shy828301@gmail.com, roman.gushchin@linux.dev, shakeelb@google.com, linmiaohe@huawei.com, william.kucharski@oracle.com, peterx@redhat.com, hughd@google.com, vbabka@suse.cz, songmuchun@bytedance.com, surenb@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, Yang Yang Subject: Re: [PATCH] mm/memcg: support control THP behaviour in cgroup Message-ID: References: <20220505033814.103256-1-xu.xin16@zte.com.cn> <6275d3e7.1c69fb81.1d62.4504@mx.google.com> <6278fa75.1c69fb81.9c598.f794@mx.google.com> <6279c354.1c69fb81.7f6c1.15e0@mx.google.com> <627a5214.1c69fb81.1b7fb.47be@mx.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <627a5214.1c69fb81.1b7fb.47be@mx.google.com> X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 414E01200B6 X-Stat-Signature: 8m1q7qc8q8w1idu1pted3hn6de1u8mtw Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=tovm3tZ+; spf=pass (imf29.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.29 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com X-HE-Tag: 1652189791-917535 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 Tue 10-05-22 11:52:51, CGEL wrote: > On Tue, May 10, 2022 at 12:00:04PM +0200, Michal Hocko wrote: > > On Tue 10-05-22 01:43:38, CGEL wrote: > > > On Mon, May 09, 2022 at 01:48:39PM +0200, Michal Hocko wrote: > > > > On Mon 09-05-22 11:26:43, CGEL wrote: > > > > > On Mon, May 09, 2022 at 12:00:28PM +0200, Michal Hocko wrote: > > > > > > On Sat 07-05-22 02:05:25, CGEL wrote: > > > > > > [...] > > > > > > > If there are many containers to run on one host, and some of them have high > > > > > > > performance requirements, administrator could turn on thp for them: > > > > > > > # docker run -it --thp-enabled=always > > > > > > > Then all the processes in those containers will always use thp. > > > > > > > While other containers turn off thp by: > > > > > > > # docker run -it --thp-enabled=never > > > > > > > > > > > > I do not know. The THP config space is already too confusing and complex > > > > > > and this just adds on top. E.g. is the behavior of the knob > > > > > > hierarchical? What is the policy if parent memcg says madivise while > > > > > > child says always? How does the per-application configuration aligns > > > > > > with all that (e.g. memcg policy madivise but application says never via > > > > > > prctl while still uses some madvised - e.g. via library). > > > > > > > > > > > > > > > > The cgroup THP behavior is align to host and totally independent just likes > > > > > /sys/fs/cgroup/memory.swappiness. That means if one cgroup config 'always' > > > > > for thp, it has no matter with host or other cgroup. This make it simple for > > > > > user to understand or control. > > > > > > > > All controls in cgroup v2 should be hierarchical. This is really > > > > required for a proper delegation semantic. > > > > > > > > > > Could we align to the semantic of /sys/fs/cgroup/memory.swappiness? > > > Some distributions like Ubuntu is still using cgroup v1. > > > > cgroup v1 interface is mostly frozen. All new features are added to the > > v2 interface. > > > > So what about we add this interface to cgroup v2? Can you come up with a sane hierarchical behavior? [...] > > > For micro-service architecture, the application in one container is not a > > > set of loosely tight processes, it's aim at provide one certain service, > > > so different containers means different service, and different service > > > has different QoS demand. > > > > OK, if they are tightly coupled you could apply the same THP policy by > > an existing prctl interface. Why is that not feasible. As you are noting > > below... > > > > > 5.containers usually managed by compose software, which treats container as > > > base management unit; > > > > ..so the compose software can easily start up the workload by using prctl > > to disable THP for whatever workloads it is not suitable for. > > prctl(PR_SET_THP_DISABLE..) can not be elegance to support the semantic we > need. If only some containers needs THP, other containers and host do not need > THP. We must set host THP to always first, and call prctl() to close THP for > host tasks and other containers one by one, It might not be the most elegant solution but it should work. Maintaining user interfaces for ever has some cost and the THP configuration space is quite large already. So I would rather not add more complication in unless that is absolutely necessary. > in this process some tasks that start before we call prctl() may > already use THP with no need. As long as all those processes have a common ancestor I do not see how that would be possible. -- Michal Hocko SUSE Labs