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 2C50CC433EF for ; Sun, 3 Apr 2022 06:47:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 50EE76B0072; Sun, 3 Apr 2022 02:46:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 497E66B0073; Sun, 3 Apr 2022 02:46:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3113C6B0074; Sun, 3 Apr 2022 02:46:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0071.hostedemail.com [216.40.44.71]) by kanga.kvack.org (Postfix) with ESMTP id 1A3636B0072 for ; Sun, 3 Apr 2022 02:46:52 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id C209E824C421 for ; Sun, 3 Apr 2022 06:46:41 +0000 (UTC) X-FDA: 79314634602.30.A555A07 Received: from mail-il1-f172.google.com (mail-il1-f172.google.com [209.85.166.172]) by imf07.hostedemail.com (Postfix) with ESMTP id 504AC4000F for ; Sun, 3 Apr 2022 06:46:41 +0000 (UTC) Received: by mail-il1-f172.google.com with SMTP id r11so4760977ila.1 for ; Sat, 02 Apr 2022 23:46:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=t6+k/4Om7VsqLidja8hb8+QMIWaL5Tmj1wC2cL00ays=; b=nOlAijP5ZZ9vsdwJxJUZqAvchhR2fSeQGoSus10DZCtVRxLYXfh3CaMWft73tMME1m t8EEPpLhVAmbmIitm4y9QYf8gD29WnqYP9IPk0DbsJRQ306l1QfJlfZBvwV0n6/apy1q kE/dBq22AAuWR+VBcGZKlXr/FEVoU2mgB22M1LxnKoR+KLx+gi822+ieZ9bQV5DPkPDX rv0cbX0UhZ/st6FHWyCx4nSEY24sHkWVOJgCK96qcxkxAp+J+AvawMuPwG3FbWM+qvsh z1YzQW9HvQJnNjv85bt720LiaBD3IDsndMwp3VULMTwSwWfSyKEqFX+sUpd6E8sAOFuU nD8g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=t6+k/4Om7VsqLidja8hb8+QMIWaL5Tmj1wC2cL00ays=; b=adfABEm7TqwJis4NA3YeXprRAmbIH8BUH/4Ili8JEv8/pAiS/tib2MISrkQK4bYdsD mtkSyYNe7wGI8iK4/nUXOJBrRQYNEFQ2IyV+1SuVhC0NthPBgSh5hZ7eZEDIFT7RDSQJ pFpDIBY4JDETGZiLQTGBywmwLBJzS3dhYph+eyMJ7zyUC7X1KoBK+IjXhPMklN1iZlts hEaG9nervqE3TT5AUJ5NViCwGuogPrH8ds43WU6II4hKvNg5Jo7IoNgbhdFsvqCmP2Vn muyHtaNaExqRVLEHTg7x+767vC2DOcClfg5oxBLbwjAfYTMQEOMfZUmT4blKBrF2WiZa rN2g== X-Gm-Message-State: AOAM531wmRSyIazHynAMV9/0mT+bqyO4ilGIuvOsyCe+cTsXBWhmnE4w FrvTUQTwCGz7ZPDUoNPKQhupYMMnb+1JRvp9/x+5sw== X-Google-Smtp-Source: ABdhPJzFIevVMEisQ9Pwvrh3Lhxnl9EwRG1TSPfzOF/+7Ua2Imr8RieK1XhYkaSWk0BECbaP9FsQ3vwbj4/V5Fwy9OA= X-Received: by 2002:a92:d94d:0:b0:2c8:45a5:926b with SMTP id l13-20020a92d94d000000b002c845a5926bmr3208155ilq.310.1648968400437; Sat, 02 Apr 2022 23:46:40 -0700 (PDT) MIME-Version: 1.0 References: <20220331084151.2600229-1-yosryahmed@google.com> <87y20nzyw4.fsf@yhuang6-desk2.ccr.corp.intel.com> In-Reply-To: <87y20nzyw4.fsf@yhuang6-desk2.ccr.corp.intel.com> From: Wei Xu Date: Sat, 2 Apr 2022 23:46:29 -0700 Message-ID: Subject: Re: [PATCH resend] memcg: introduce per-memcg reclaim interface To: "Huang, Ying" Cc: Michal Hocko , Yosry Ahmed , Johannes Weiner , Shakeel Butt , Andrew Morton , David Rientjes , Tejun Heo , Zefan Li , Roman Gushchin , cgroups@vger.kernel.org, linux-doc@vger.kernel.org, Linux Kernel Mailing List , Linux MM , Jonathan Corbet , Yu Zhao , Dave Hansen , Greg Thelen Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: e4akcgaydxididgor4ne9q99ccofdz8h Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=nOlAijP5; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf07.hostedemail.com: domain of weixugc@google.com designates 209.85.166.172 as permitted sender) smtp.mailfrom=weixugc@google.com X-Rspamd-Queue-Id: 504AC4000F X-HE-Tag: 1648968401-145481 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 Sat, Apr 2, 2022 at 1:13 AM Huang, Ying wrote: > > Wei Xu writes: > > > On Fri, Apr 1, 2022 at 6:54 AM Michal Hocko wrote: > >> > >> On Thu 31-03-22 08:41:51, Yosry Ahmed wrote: > >> > From: Shakeel Butt > >> > > > [snip] > > >> > Possible Extensions: > >> > -------------------- > >> > > >> > - This interface can be extended with an additional parameter or flags > >> > to allow specifying one or more types of memory to reclaim from (e.g. > >> > file, anon, ..). > >> > > >> > - The interface can also be extended with a node mask to reclaim from > >> > specific nodes. This has use cases for reclaim-based demotion in memory > >> > tiering systens. > >> > > >> > - A similar per-node interface can also be added to support proactive > >> > reclaim and reclaim-based demotion in systems without memcg. > >> > > >> > For now, let's keep things simple by adding the basic functionality. > >> > >> Yes, I am for the simplicity and this really looks like a bare minumum > >> interface. But it is not really clear who do you want to add flags on > >> top of it? > >> > >> I am not really sure we really need a node aware interface for memcg. > >> The global reclaim interface will likely need a different node because > >> we do not want to make this CONFIG_MEMCG constrained. > > > > A nodemask argument for memory.reclaim can be useful for memory > > tiering between NUMA nodes with different performance. Similar to > > proactive reclaim, it can allow a userspace daemon to drive > > memcg-based proactive demotion via the reclaim-based demotion > > mechanism in the kernel. > > I am not sure whether nodemask is a good way for demoting pages between > different types of memory. For example, for a system with DRAM and > PMEM, if specifying DRAM node in nodemask means demoting to PMEM, what > is the meaning of specifying PMEM node? reclaiming to disk? > > In general, I have no objection to the idea in general. But we should > have a clear and consistent interface. Per my understanding the default > memcg interface is for memory, regardless of memory types. The memory > reclaiming means reduce the memory usage, regardless of memory types. > We need to either extending the semantics of memory reclaiming (to > include memory demoting too), or add another interface for memory > demoting.