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 AF4C9C30653 for ; Tue, 25 Jun 2024 07:47:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 25CB36B0321; Tue, 25 Jun 2024 03:47:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 20D5B6B0322; Tue, 25 Jun 2024 03:47:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0FC836B0324; Tue, 25 Jun 2024 03:47:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id E32C16B0321 for ; Tue, 25 Jun 2024 03:47:53 -0400 (EDT) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 7E7ECA04F1 for ; Tue, 25 Jun 2024 07:47:53 +0000 (UTC) X-FDA: 82268632026.27.D26BE46 Received: from mail-lj1-f174.google.com (mail-lj1-f174.google.com [209.85.208.174]) by imf12.hostedemail.com (Postfix) with ESMTP id A605240009 for ; Tue, 25 Jun 2024 07:47:51 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=EQzzVFFf; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf12.hostedemail.com: domain of ryncsn@gmail.com designates 209.85.208.174 as permitted sender) smtp.mailfrom=ryncsn@gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1719301660; a=rsa-sha256; cv=none; b=AW7ml0iqoygWLaZuBJ7F/rZ6KGVvNp8non3wj9YG9XncKk3SM2RxR+bU/zBiIB4dsTDO/b hnJgv2LnG1H2rbdYLFjAOzGMhtlZSiYZDGZgM+uOBCwVyCcc/tw2sclenjl64J2XTt//qx BYcyVO4kvby+eLND4thgCF6wLeEQc7w= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=EQzzVFFf; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf12.hostedemail.com: domain of ryncsn@gmail.com designates 209.85.208.174 as permitted sender) smtp.mailfrom=ryncsn@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1719301660; 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=/h2LcRd/DugQGxUOTCRGTFk1KswMZJTr8HIVE5tV0mE=; b=YPBC9nBA9efBL4khwwNq6Mf06KsFqpCJhP5XoX2mhTa4zfYDggi83ylRXblTdivZjYH4Gc qDbwIss8f7/5UIBS6nBIKZjZVhveny51/5iDmDirr5b55S50HlS4BURZ9nLow5ThFEn8Os KLYYQoV6WtCACPyoSWGyhArM7yorkU0= Received: by mail-lj1-f174.google.com with SMTP id 38308e7fff4ca-2ec595d0acbso28196171fa.1 for ; Tue, 25 Jun 2024 00:47:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1719301670; x=1719906470; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=/h2LcRd/DugQGxUOTCRGTFk1KswMZJTr8HIVE5tV0mE=; b=EQzzVFFf59Aui4FLwfrA7tv4lPGSQYx5thlmT8BfkURZxFTvVzQRrjxmjLDvv+tHOr tdatH6mY87GQMvOB6fPo4wypaUGu4vQjDvDS/gMT5+ABH01uFjJ8//MJF40/xXTgtE5w hv/z9r9gJkFqUM3zmZc1WTVRN6Oi9iqxB1HZoSvNO053YnXNTOfFzgGo316Em3NSWFnN uubxD0N5JjWJMwRK8Gumps9AhR0zqi/P7wCuosmvg9vlZT2btdp5a7LjGUTO32xeDmXX vMEwqiJwiaEI7nfOcpnN61K/pUQ4eETA3O8jzZ0tWR1iHQ2ztx2Km1+fJcMfqDh5bLQe 2xlA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1719301670; x=1719906470; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=/h2LcRd/DugQGxUOTCRGTFk1KswMZJTr8HIVE5tV0mE=; b=T1cFaGNZ4uIUId4O/yINfECMBFLhLfd4Vn8/zlEI5UBf/WFSdsBSEpHQHRUuDabrdQ dL9m6+PS9u4w8px3S6qWv1zPPQoG/zk/x3S2kW4cfRzWXx5+DowEE/25TydXnoMevitU y7vBzW8GOxig3uxEOchliCxfpV97oZmBI7U4vLf1OI0Wrl2bJkq6iyBxwi1J2489YVd/ TKiYjIFMCnFTgn36EgDlBxTQjfMERKG0Og2Bjo1OtSHksoUzQiRCcV/67iEQRA6y0+m/ GEfJvzeobg8BPf1QfHnXfJshIQY8Lxszql0wevfR0XJ8V9cfZzx0qLbkOoUwyJQPP/fh FToA== X-Gm-Message-State: AOJu0YzV20gvumWB82nIoleGeKw5yHZBP/ebbeITx5yLgrQeXuwxtSkj DuGUmcqKsZXb7SmbkerPZMip0oqn3p1SqDgUO9em8Zd3sJ1IL2dB/y1fyqfKBRSkeRrK6C+xf5G ZjCenIbfPTdmJZHQ9vJ+d0F1kERA= X-Google-Smtp-Source: AGHT+IGp7mhSnafEfXwHXmef51UAantdM/1StSxSU2zavpjl8b3m71H/UfFh4Le5eoUs2SJTeOLbdGI0GcZo27mDkD0= X-Received: by 2002:a2e:720c:0:b0:2ec:4e79:b416 with SMTP id 38308e7fff4ca-2ec5b2fc299mr48706351fa.6.1719301669635; Tue, 25 Jun 2024 00:47:49 -0700 (PDT) MIME-Version: 1.0 References: <20240624175313.47329-1-ryncsn@gmail.com> <20240624142654.7b7aa167b8fa61fb805a732e@linux-foundation.org> In-Reply-To: <20240624142654.7b7aa167b8fa61fb805a732e@linux-foundation.org> From: Kairui Song Date: Tue, 25 Jun 2024 15:47:32 +0800 Message-ID: Subject: Re: [PATCH 0/7] Split list_lru lock into per-cgroup scope To: Andrew Morton Cc: linux-mm@kvack.org, Matthew Wilcox , Johannes Weiner , Roman Gushchin , Waiman Long , Shakeel Butt , Nhat Pham , Michal Hocko , Chengming Zhou , Qi Zheng , Muchun Song , Chris Li , Yosry Ahmed , "Huang, Ying" Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: A605240009 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: sp81kfnnbjbszmdq8bbz4z5w558uj1n8 X-HE-Tag: 1719301671-533564 X-HE-Meta: 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 0l+E59HQ EWgCKXrto/qLfft3vfYPsCe06/GnqnZG19N+fLqRSCKi9+ElQKOn8M4FmMvTGwAndhp0DpLtZWgSFQBrgJCtc/3/Mzf2IupZ44JPtc9hojPftXz1LURBbp0yDkwQqNRGq5cFMKnidleR/MSy0pw/s6Af4lypwglylWucUJGBgmw69+pJ8DW2RC4wwMJcy4s3Mndh+79Ggfsg7Ac8Otq98sXP4TACjeqPSaIvI+WCfoq7o1ixcLVNKOUORnkxTQJzxEvcBU4mXduOeziSjfWGcayMxogdY/FZAPNsn5r6eKIOgeyFiWAL70q4mdqSTPbRpF7kQJpUFz68+YkF0PLkRqZ662SgcgOBeMTq1LJcBdr6pq4vqzCjw4EqYDI4NPUQoAfIKjAwtfFKAYGWF2KUHq6u/7ypy0qKGnzpzE7hijDoJa3Y= 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: List-Subscribe: List-Unsubscribe: On Tue, Jun 25, 2024 at 5:26=E2=80=AFAM Andrew Morton wrote: > > On Tue, 25 Jun 2024 01:53:06 +0800 Kairui Song wrote: > > > Currently, every list_lru has a per-node lock that protects adding, > > deletion, isolation, and reparenting of all list_lru_one instances > > belonging to this list_lru on this node. This lock contention is heavy > > when multiple cgroups modify the same list_lru. > > > > This can be alleviated by splitting the lock into per-cgroup scope. > > I'm wavering over this. We're at -rc5 and things generally feel a bit > unstable at present. > > The performance numbers are nice for extreme workloads, but can you > suggest how much benefit users will see in more typical workloads? Hi, the contention issue might be minor if the memory stress is low, but still beneficial, and this series optimizes the cgroup initialization too. The memhog test I provided is tested on a 32 core system with 64 cgroups (I forgot to provide this detail, sry), not a very extreme configuration actually, considering it's not rare to have thousands of cgroups on a system nowadays. They all sharing a global lock is definitely not a good idea. The issue is barely observable for things like desktop usage though. > > Anyway, opinions are sought and I'd ask people to please review this > work promptly if they feel is it sufficiently beneficial. More reviews are definitely beneficial.