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 AE347C3DA5D for ; Mon, 22 Jul 2024 20:02:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D31F66B0085; Mon, 22 Jul 2024 16:02:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CBB306B0088; Mon, 22 Jul 2024 16:02:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B5C276B0089; Mon, 22 Jul 2024 16:02:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 8F3BD6B0085 for ; Mon, 22 Jul 2024 16:02:12 -0400 (EDT) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 8AE07A6225 for ; Mon, 22 Jul 2024 20:02:11 +0000 (UTC) X-FDA: 82368460062.02.1092C44 Received: from out-185.mta0.migadu.com (out-185.mta0.migadu.com [91.218.175.185]) by imf10.hostedemail.com (Postfix) with ESMTP id AA6FCC0020 for ; Mon, 22 Jul 2024 20:02:08 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=IjVJkToG; spf=pass (imf10.hostedemail.com: domain of shakeel.butt@linux.dev designates 91.218.175.185 as permitted sender) smtp.mailfrom=shakeel.butt@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1721678468; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=ivKGMe+zLq7jQ9Li9BCjPFPZ7oqpm0THNZ5W1uzUhes=; b=YCa/tFzJpHHb6RpXcK4NdM9bWEZYgZNxkAdxtYxwH3638x6+MGcmkMSJ4jcXT9qlM7R9n2 UM/e0QmOgXbukJJBepeuAGSqde+QheAqq+qH9PZWNCk87R9sOG8EPAEhy57q6GdstmsRkC apwqU+WWYAaIHxvm03Mf245av1gfrCU= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=IjVJkToG; spf=pass (imf10.hostedemail.com: domain of shakeel.butt@linux.dev designates 91.218.175.185 as permitted sender) smtp.mailfrom=shakeel.butt@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1721678468; a=rsa-sha256; cv=none; b=GAp9mkkVXk+FgYt4X6ZDuDFuE/qSFucedBPYhSul1kxP/EKpT/6ZUXMHjAre4cq0cUFFTR XPkZ0h+154fob3AKQzZq0UmnkqnMkgZXcjy6rz8oNiWMCJepE+vpDoRtMeQSt+C9pT0p9A JaqHltazIHFFi1w5wJy4u5Xv0NMibvs= X-Envelope-To: yosryahmed@google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1721678526; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ivKGMe+zLq7jQ9Li9BCjPFPZ7oqpm0THNZ5W1uzUhes=; b=IjVJkToGM18K/3eL+3aWlIHarEsLnUVfTmjMIi0c1Igq+MqWvQPpzSqWfXQNyiI/caEOTs SoMF+xhQ3yBPr4YCZq85ajT8E6V8cuCn8QSlXMxuzZwUsvqayTzLLWRxcUTQ2Idn7pDipV APRnBeVCzRfj6LPBFzTh7lkYHaL6dcY= X-Envelope-To: hawk@kernel.org X-Envelope-To: tj@kernel.org X-Envelope-To: cgroups@vger.kernel.org X-Envelope-To: hannes@cmpxchg.org X-Envelope-To: lizefan.x@bytedance.com X-Envelope-To: longman@redhat.com X-Envelope-To: kernel-team@cloudflare.com X-Envelope-To: linux-mm@kvack.org X-Envelope-To: linux-kernel@vger.kernel.org Date: Mon, 22 Jul 2024 13:02:00 -0700 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Shakeel Butt To: Yosry Ahmed Cc: Jesper Dangaard Brouer , tj@kernel.org, cgroups@vger.kernel.org, hannes@cmpxchg.org, lizefan.x@bytedance.com, longman@redhat.com, kernel-team@cloudflare.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V7 1/2] cgroup/rstat: Avoid thundering herd problem by kswapd across NUMA nodes Message-ID: References: <172070450139.2992819.13210624094367257881.stgit@firesoul> <100caebf-c11c-45c9-b864-d8562e2a5ac5@kernel.org> <5ccc693a-2142-489d-b3f1-426758883c1e@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: AA6FCC0020 X-Stat-Signature: 77st3mugakq73b3oo4ywxmawfkab3khe X-Rspam-User: X-HE-Tag: 1721678528-527386 X-HE-Meta: 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 rTy7nvrF f1MJJuN1yuPF4i1zcN8Y61EubedyM+xGpTV6syanEFbwegekHp4mHAX4A57XgCsJg/9GP8uLrqf+BBxEt9GYMGQgTwIo2sa2+g0Ntd2+2yjcgEaq9W09qx/542/wUAI1vdH+e16JG2NYFaJDTvqA66dLigeQn04UuaCX+7dNWWK1Uo9EHpii/6q2Sz5eURCRIU8zbsk/jV/BGBDQ= X-Bogosity: Ham, tests=bogofilter, spamicity=0.003381, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Jul 19, 2024 at 09:52:17PM GMT, Yosry Ahmed wrote: > On Fri, Jul 19, 2024 at 3:48 PM Shakeel Butt wrote: > > > > On Fri, Jul 19, 2024 at 09:54:41AM GMT, Jesper Dangaard Brouer wrote: > > > > > > > > > On 19/07/2024 02.40, Shakeel Butt wrote: > > > > Hi Jesper, > > > > > > > > On Wed, Jul 17, 2024 at 06:36:28PM GMT, Jesper Dangaard Brouer wrote: > > > > > > > > > [...] > > > > > > > > > > > > > > > Looking at the production numbers for the time the lock is held for level 0: > > > > > > > > > > @locked_time_level[0]: > > > > > [4M, 8M) 623 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ | > > > > > [8M, 16M) 860 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@| > > > > > [16M, 32M) 295 |@@@@@@@@@@@@@@@@@ | > > > > > [32M, 64M) 275 |@@@@@@@@@@@@@@@@ | > > > > > > > > > > > > > Is it possible to get the above histogram for other levels as well? > > > > > > Data from other levels available in [1]: > > > [1] > > > https://lore.kernel.org/all/8c123882-a5c5-409a-938b-cb5aec9b9ab5@kernel.org/ > > > > > > IMHO the data shows we will get most out of skipping level-0 root-cgroup > > > flushes. > > > > > > > Thanks a lot of the data. Are all or most of these locked_time_level[0] > > from kswapds? This just motivates me to strongly push the ratelimited > > flush patch of mine (which would be orthogonal to your patch series). > > Jesper and I were discussing a better ratelimiting approach, whether > it's measuring the time since the last flush, or only skipping if we > have a lot of flushes in a specific time frame (using __ratelimit()). > I believe this would be better than the current memcg ratelimiting > approach, and we can remove the latter. > > WDYT? The last statement gives me the impression that you are trying to fix something that is not broken. The current ratelimiting users are ok, the issue is with the sync flushers. Or maybe you are suggesting that the new ratelimiting will be used for all sync flushers and current ratelimiting users and the new ratelimiting will make a good tradeoff between the accuracy and potential flush stall?