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=-1.0 required=3.0 tests=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 BAABAC4BA3B for ; Thu, 27 Feb 2020 09:59:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 82AAE222C2 for ; Thu, 27 Feb 2020 09:59:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 82AAE222C2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2420D6B0006; Thu, 27 Feb 2020 04:59:03 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1F33D6B0007; Thu, 27 Feb 2020 04:59:03 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0B9BE6B0008; Thu, 27 Feb 2020 04:59:03 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0069.hostedemail.com [216.40.44.69]) by kanga.kvack.org (Postfix) with ESMTP id E63D46B0006 for ; Thu, 27 Feb 2020 04:59:02 -0500 (EST) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 892B61801A08B for ; Thu, 27 Feb 2020 09:59:02 +0000 (UTC) X-FDA: 76535458524.02.snail19_4ee43a5fbc124 X-HE-Tag: snail19_4ee43a5fbc124 X-Filterd-Recvd-Size: 3475 Received: from mail-wr1-f66.google.com (mail-wr1-f66.google.com [209.85.221.66]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Thu, 27 Feb 2020 09:59:01 +0000 (UTC) Received: by mail-wr1-f66.google.com with SMTP id m16so2465205wrx.11 for ; Thu, 27 Feb 2020 01:59:02 -0800 (PST) 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; bh=VQ5cODCZxfkuaY7C2X27hLMvpBk5ErfD2dcMR1H0vUQ=; b=ZAKQFUvgixYkRZkpkLL9giLGpYAGNQrxjaljHp1/snV8m5wHns1Vt30JZ+je5v4oUL zOQi8h6r7e0suan+WXih1awPrGyxbAPJkUhpLi9NVVNPi6q0GduYL6Jo+GWRJcQtuTog 6Ye1ovA5Scrcvi38sV6kwYi+ZrOH4rHqKJxy9RWIY57BPNQ8V6EB6yyCpGiMGmBTLSiu jwhbI5nG1ndp3daRsvAooJrtybb00IhGLW+T7xpKC2JHS0pPk1lXp9clnIV1VuKA49n1 dM/iMnCmsgFkQNUlcw/TbePP4oex+SklXOXNfcKUcJAIiGpD+XDlsGG3k7CLH4HO087K +fTw== X-Gm-Message-State: APjAAAWOqGEKOAGfiDaCTsgtYefeqpqwp42uPnCRa9yYGbV0PbthfUKC rNk5HkUfJKWu9Wbwsv8qpyU= X-Google-Smtp-Source: APXvYqyIHDqVdj4EvcgNGGEOqLGP0YnWFvgtDohXEArkdrFlu3228O8uGCdziWphEpOylyvx14xPRQ== X-Received: by 2002:adf:ed84:: with SMTP id c4mr3890509wro.24.1582797540999; Thu, 27 Feb 2020 01:59:00 -0800 (PST) Received: from localhost (prg-ext-pat.suse.com. [213.151.95.130]) by smtp.gmail.com with ESMTPSA id a198sm7226849wme.12.2020.02.27.01.58.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Feb 2020 01:58:59 -0800 (PST) Date: Thu, 27 Feb 2020 10:58:59 +0100 From: Michal Hocko To: Yang Shi Cc: Johannes Weiner , Shakeel Butt , Andrew Morton , Tejun Heo , Roman Gushchin , Linux MM , Cgroups , LKML , Kernel Team Subject: Re: [PATCH] mm: memcontrol: asynchronous reclaim for memory.high Message-ID: <20200227095859.GA3771@dhcp22.suse.cz> References: <20200219181219.54356-1-hannes@cmpxchg.org> <20200226222642.GB30206@cmpxchg.org> <2be6ac8d-e290-0a85-5cfa-084968a7fe36@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2be6ac8d-e290-0a85-5cfa-084968a7fe36@linux.alibaba.com> 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 26-02-20 16:12:23, Yang Shi wrote: [...] > Actually I'm wondering if we really need account CPU cycles used by > background reclaimer or not. For our usecase (this may be not general), the > purpose of background reclaimer is to avoid latency sensitive workloads get > into direct relcaim (avoid the stall from direct relcaim). In fact it just > "steal" CPU cycles from lower priority or best-effort workloads to guarantee > latency sensitive workloads behave well. If the "stolen" CPU cycles are > accounted, it means the latency sensitive workloads would get throttled from > somewhere else later, i.e. by CPU share. I believe we need to because that work is not for free and so you are essentially stealing those CPUs cycles from everybody else outside of your throttled cgroup. -- Michal Hocko SUSE Labs