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 91735C001DE for ; Fri, 4 Aug 2023 18:59:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CD9A68D0001; Fri, 4 Aug 2023 14:59:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C62926B0072; Fri, 4 Aug 2023 14:59:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ADBD38D0001; Fri, 4 Aug 2023 14:59:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 9AF326B0071 for ; Fri, 4 Aug 2023 14:59:45 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 504CE160794 for ; Fri, 4 Aug 2023 18:59:45 +0000 (UTC) X-FDA: 81087336330.21.3A7B028 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf23.hostedemail.com (Postfix) with ESMTP id 255D9140010 for ; Fri, 4 Aug 2023 18:59:42 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=DkvzRZsw; spf=pass (imf23.hostedemail.com: domain of lkarpins@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=lkarpins@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1691175583; a=rsa-sha256; cv=none; b=lqkFqMJ+O5ffFD/liy8cj2UyIPZO9DTFU+9FkAiCXuW0HGYDxQ4bfSDWL6oaZjVv5Pi9iL YM9CUchxIBonnzca26Qg4D7qdiLCYof6+Sx5h+y2W5F6TAAcI+HRDoNOvsfaM/TQt0u8AI t5+bCdn2IIVrLEEY2PiFqwXEeDzbdPA= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=DkvzRZsw; spf=pass (imf23.hostedemail.com: domain of lkarpins@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=lkarpins@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1691175583; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=8TRlrLFCMco4XO+xD44hANqOAJKBhYI/ogDyetWODDc=; b=0eBeisHH2WuA04eyYuENFguyfI4Vz4nsqT3t00aITkOis/LeUoOcCTD7HkUdT/QFNPrzPU 1s82etplpCwntJ/92Xq3nyuwu12U4l2QSA677gbUu5dxslOExgAJXt6h8/IRfN0Y4sv6ip REJXpZd15x8n4yt7FTRHfnnE8KbeN48= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1691175582; 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: in-reply-to:in-reply-to:references:references; bh=8TRlrLFCMco4XO+xD44hANqOAJKBhYI/ogDyetWODDc=; b=DkvzRZsw6AnsiH0hnBoIaVgjbubMegcslV/GzKI/nS1/+WQ3Nb+5nSACkOhQ3PUEOzV+vb UJF094doG/8mjk2AH7HAnyaYODadgRJXJnHi0E1tUEkPvRQmRzVgzsohm/Blc9w3q/zBYi nv6SODTQGM7fRUsMPA/tyGKJ+omCs8c= Received: from mail-qk1-f199.google.com (mail-qk1-f199.google.com [209.85.222.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-195-jEGasHHrPc-CQMcCWYLJhQ-1; Fri, 04 Aug 2023 14:59:40 -0400 X-MC-Unique: jEGasHHrPc-CQMcCWYLJhQ-1 Received: by mail-qk1-f199.google.com with SMTP id af79cd13be357-76c93466e4cso255411485a.3 for ; Fri, 04 Aug 2023 11:59:40 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691175580; x=1691780380; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=8TRlrLFCMco4XO+xD44hANqOAJKBhYI/ogDyetWODDc=; b=V8e0CD+soEelZGUIRU6Db6K8ZxZfHal6z2/TsrZDKN4XgnTTJh4zqdIyN/JJ8TWhaP Vh8Kvn4z60YoIgTGYofOzljAiviqjVsetvwtjdeHtVeBozXkAAOzFfUZLvVxIoQm5yWe IKjILiaWjXeU3XblIun38dD9WMfxdCJNiAMDSuy68BIa4azaM1HPrOZqhZVbC9Sd/El4 5F4VcGdttO5x/OW19QiJDt55M/HVffdUUEBEMD+ZeV4uCH2VeB/dUqOWzgb5bDv5Q+eg GXhlF6pEgMm392tKZDLbEttdrHWHEJrsshpH9n4j2F8PC9RB0MxjLcGUsZkDpfjPWz5M 1oCg== X-Gm-Message-State: AOJu0YxOpZpzr255glAWq27GxDkUJ6DCnS6OchkV+L2jhKFuuGr89MPP 49rs5vgKKC8BYEe0AKsBcJwM7ZVVp/J/3xGATqSOd76HHAmxS+v+9J8U9uBzWih/XXl6VGWGN1/ zR6NIk0Wk3I4= X-Received: by 2002:a0c:eb02:0:b0:63c:d901:d5d5 with SMTP id j2-20020a0ceb02000000b0063cd901d5d5mr2546175qvp.34.1691175579970; Fri, 04 Aug 2023 11:59:39 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEd/MtSKV8LZK8i31DkhA+HpBPtfBIuzuujDU0hnNApM9DNuN22ObPimY7Yz0Q78IzG0Slmcw== X-Received: by 2002:a0c:eb02:0:b0:63c:d901:d5d5 with SMTP id j2-20020a0ceb02000000b0063cd901d5d5mr2546163qvp.34.1691175579724; Fri, 04 Aug 2023 11:59:39 -0700 (PDT) Received: from fedora ([174.89.37.244]) by smtp.gmail.com with ESMTPSA id y14-20020a0ce04e000000b0063f7a2847bcsm32703qvk.51.2023.08.04.11.59.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Aug 2023 11:59:38 -0700 (PDT) Date: Fri, 4 Aug 2023 14:59:28 -0400 From: Lucas Karpinski To: Johannes Weiner Cc: Andrew Morton , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Tejun Heo , Zefan Li , Shuah Khan , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] selftests: cgroup: fix test_kmem_memcg_deletion false positives Message-ID: References: <20230804163716.GA337691@cmpxchg.org> MIME-Version: 1.0 In-Reply-To: <20230804163716.GA337691@cmpxchg.org> User-Agent: NeoMutt/20230517 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 255D9140010 X-Stat-Signature: 5c5mgzmutzib1rheom3e1dc5itsmeq78 X-Rspam-User: X-HE-Tag: 1691175582-399076 X-HE-Meta: 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 v1vE4t6B 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 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 Fri, Aug 04, 2023 at 12:37:16PM -0400, Johannes Weiner wrote: > On Fri, Aug 04, 2023 at 11:37:33AM -0400, Lucas Karpinski wrote: > > The test allocates dcache inside a cgroup, then destroys the cgroups and > > then checks the sanity of numbers on the parent level. The reason it > > fails is because dentries are freed with an RCU delay - a debugging > > sleep shows that usage drops as expected shortly after. > > > > Insert a 1s sleep after completing the cgroup creation/deletions. This > > should be good enough, assuming that machines running those tests are > > otherwise not very busy. This commit is directly inspired by Johannes > > over at the link below. > > > > Link: https://lore.kernel.org/all/20230801135632.1768830-1-hannes@cmpxchg.org/ > > > > Signed-off-by: Lucas Karpinski > > Maybe I'm missing something, but there isn't a limit set anywhere that > would cause the dentries to be reclaimed and freed, no? When the > subgroups are deleted, the objects are just moved to the parent. The > counters inside the parent (which are hierarchical) shouldn't change. > > So this seems to be a different scenario than test_kmem_basic. If the > test is failing for you, I can't quite see why. > You're right, the parent inherited the counters and it should behave the same whether I'm directly removing the child or if I was moving it under another cgroup. I do see the behaviour you described on my x86_64 setup, but the wrong behaviour on my aarch64 dev. platform. I'll take a closer look, but just wanted to leave an example here of what I see. Example of slab size pre/post sleep: slab_pre = 18164688, slab_post = 3360000 Thanks, Lucas