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 E7C2DC369C9 for ; Sun, 20 Apr 2025 00:14:38 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B31546B00A2; Sat, 19 Apr 2025 20:14:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id ADFAA6B00A4; Sat, 19 Apr 2025 20:14:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9A93D6B00A5; Sat, 19 Apr 2025 20:14:36 -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 7CA426B00A2 for ; Sat, 19 Apr 2025 20:14:36 -0400 (EDT) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 3DAA3B437F for ; Sun, 20 Apr 2025 00:14:37 +0000 (UTC) X-FDA: 83352500994.29.A8D79DA Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf30.hostedemail.com (Postfix) with ESMTP id EEF3580004 for ; Sun, 20 Apr 2025 00:14:34 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=iYNMZZD5; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf30.hostedemail.com: domain of llong@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=llong@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1745108075; a=rsa-sha256; cv=none; b=hib9I0PquLXrZnO8iSvrlnH3JL0NiWL4UbK7jJpChLVZOd0hf5rIAX2cXwbleQv6W0Qb4d 9skgq5D0AY7RCPazydkQrsYiE0xbq0YX80SDkvCeNCQBfYHLhsLbL1IzTxr9nJLFqYCpVH bnSsgeFRHE/gdIuCTEdKQld7SEMJEVU= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=iYNMZZD5; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf30.hostedemail.com: domain of llong@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=llong@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1745108075; 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=NuYZPgib8XXRmGrAdptMQ05xG1oDA8T8AcbL73YF0K4=; b=3mNY49cdiVrj26pTJxMAdfjG9UlZqgY5mEPiRQYkx82lX2oLsUGoroEMhbfmxoAr/FStIs mANDvUdZeyRdsQT83qVmOrZzOdbVLiYyjq9QJhBHvZsxuvCZ0LK53FIArAZzD0+dUikKo/ 11RtIqfLDvXXJdA0i7HTrlXd01r7utI= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1745108074; 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=NuYZPgib8XXRmGrAdptMQ05xG1oDA8T8AcbL73YF0K4=; b=iYNMZZD5khS8VivJ1+OgtdlzFf2zZY5tGKvWFwYkknc6KjXDnxS73hcfQ49xWfpVxFj+ws 4QvWlEKW4MQKAOTHoG/VDNV1bTAcHEE8MOinmNuqEb1PgsZCa7cQVpWULle8Sj8g6k4dYI jJx14GvaBKTvBomN5Aope83uI4q6wXw= 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-318-gJAStOg5OOytdYt47rM37w-1; Sat, 19 Apr 2025 20:14:32 -0400 X-MC-Unique: gJAStOg5OOytdYt47rM37w-1 X-Mimecast-MFC-AGG-ID: gJAStOg5OOytdYt47rM37w_1745108072 Received: by mail-qk1-f199.google.com with SMTP id af79cd13be357-7c579d37eeeso429811585a.0 for ; Sat, 19 Apr 2025 17:14:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1745108072; x=1745712872; h=content-transfer-encoding:in-reply-to:content-language:references :cc:to:subject:user-agent:mime-version:date:message-id:from :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=NuYZPgib8XXRmGrAdptMQ05xG1oDA8T8AcbL73YF0K4=; b=J+UzlVAVWwHljNBlvispFEetUYEKxftuutfNpSkXQfKMWSmcbmPVFeGQS/gMO2cNaW URnWbWrKw7Avu9f/9UAybLFfaLfYkbW0cLjgU8pWffAegfHOxcDoaWlWzmEphmZKn2Uj nHOim+itmxFr7yRaMl5uwDQz2YApt8vTEGC9mJukCmLjZD/DMND6azCwCuSqoZlKVcV9 fJHg8BXfICpKRpqLlMer2WXs1ZHpqUh+GCd35PwL5T22k1b1R048qajcJHRaTa2SDNUR ooBxs+/wquy95fahCTpMkWGmdVOe37hK8H+NynbmSdzCxYlzATDVG/NF2OntXze2kfbT 2tJA== X-Gm-Message-State: AOJu0YxMJMv73JEBnsbAgoXD3GEtrUIk03T10GmHGf+t2TTIYlcQ6TJs EQMeP3RcsLYT+UHlFATce0Pw2BviY6lfXQLO5mjedeiBB6kuE4oRynnJTsbJ9aFcN+/ydK/DGTb XBZIWoW78poCLUxOx/4lhBIPPnYGSs05baMW3gxm9yDEmtTzx X-Gm-Gg: ASbGncv3Os70w1NXEPwFK8UJLha04govEAzX1CKHBlhMVM8TD+bb8K8lzOyLqaDweG/ oihTlLQXvy+/jpGU9fc9Dr+to0nBWc4wsK/GKa4sIFGR3H6jrN2qVusumVwCtSi/7lqA/Ic8yuY LU9k5i9RyhusYa/EmMVm/w+znib/E8ASBpIi/Big5Yde2mxAshKZgxP5W1D9N9eGPgOsPKxl/0B taP4GoQrSZHRCwo/aNG2xh0Yrc/rKtoxtXuPHZPFbLmt+gLAPrYsn05OTHHxzqhcTdKPXt5T5Dm to7rH02Z3rs9/HS8zCnc9LbeWEP02/YoQ3cR82r3UznxfXPoPQ== X-Received: by 2002:a05:620a:2909:b0:7c9:2425:a7ae with SMTP id af79cd13be357-7c927fb657cmr1078312485a.29.1745108072044; Sat, 19 Apr 2025 17:14:32 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFta6KY5a629CPuxTTV5gcifkgwp8GViCo40FJtDLnnoc0MmUJKHFN4xPTcWiE6U+QjlnfB4g== X-Received: by 2002:a05:620a:2909:b0:7c9:2425:a7ae with SMTP id af79cd13be357-7c927fb657cmr1078310185a.29.1745108071708; Sat, 19 Apr 2025 17:14:31 -0700 (PDT) Received: from [192.168.130.170] (67-212-218-66.static.pfnllc.net. [67.212.218.66]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7c9282cca4esm232635685a.50.2025.04.19.17.14.30 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 19 Apr 2025 17:14:31 -0700 (PDT) From: Waiman Long X-Google-Original-From: Waiman Long Message-ID: Date: Sat, 19 Apr 2025 20:14:29 -0400 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 2/2] vmscan,cgroup: apply mems_effective to reclaim To: Shakeel Butt , Gregory Price Cc: linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev, muchun.song@linux.dev, tj@kernel.org, mkoutny@suse.com, akpm@linux-foundation.org References: <20250419053824.1601470-1-gourry@gourry.net> <20250419053824.1601470-3-gourry@gourry.net> In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: C0dQt0noOthqQ6ob5PHO7BpUfMuG-uJ_El7qo9nsBFw_1745108072 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: EEF3580004 X-Stat-Signature: nz5ihnbqyg7jpnggcmy53ysxetzyxu1t X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1745108074-837355 X-HE-Meta: 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 r4p/4wIV YaHtM7DXVlv3CNinPjiYk6jM1+mcUdifh30yvNzT4Ok6LuMWC4LC1MzyigzwlKiuOWtxSRXh7eGPIQn1bMGwg/JSeYjG/1pF4MJTjEkjcqdPHQmyDBgrr48DVhmhe72Oc83ogJSgZW+DMZ1j77vKbuWmepNPVE9ACUk1+6d5B+i7+5/OfvXlilPEbhHwDckdLLV2o8/HV/HJkhrQpF1rAbrjmTQetxSJKxVhYspQgqTB2YUJoGYtZeo/XJokKoVPywtxCmLkGgBr4l3v4JFuXnD6M6lfXDWcAWhGSp/CJEVB5ipR4jqei8psWe4s27+X7myLNovwoB7RsVWrvrlRJfqGz4PJU3IjiiuVGVIocmSZEfJyRysZuUgGxp9ShDhwXvvz1e8fBUFvUYWoVjyTweCAP7rResqaa/dFcrzVZIWiyM8ASYilHCkYljg== 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 4/19/25 2:48 PM, Shakeel Butt wrote: > On Sat, Apr 19, 2025 at 01:38:24AM -0400, Gregory Price wrote: >> >> +bool cpuset_node_allowed(struct cgroup *cgroup, int nid) >> +{ >> + struct cgroup_subsys_state *css; >> + unsigned long flags; >> + struct cpuset *cs; >> + bool allowed; >> + >> + css = cgroup_get_e_css(cgroup, &cpuset_cgrp_subsys); >> + if (!css) >> + return true; >> + >> + cs = container_of(css, struct cpuset, css); >> + spin_lock_irqsave(&callback_lock, flags); > Do we really need callback_lock here? We are not modifying and I am > wondering if simple rcu read lock is enough here (similar to > update_nodemasks_hier() where parent's effective_mems is accessed within > rcu read lock). The callback_lock is required to ensure the stability of the effective_mems which may be in the process of being changed if not taken. Cheers, Longman > >> + /* On v1 effective_mems may be empty, simply allow */ >> + allowed = node_isset(nid, cs->effective_mems) || >> + nodes_empty(cs->effective_mems); >> + spin_unlock_irqrestore(&callback_lock, flags); >> + css_put(css); >> + return allowed; >> +}