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bh=EKRe6KWYgeFiWWRxv1SzpLFERN+u/q9W6swOVGSf+Ko=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=sSnu9b5nlPnsxvsV5oLdBcYxp66/68wU/Y8129B1Zki2o8i1c+P9oj0N2zJ+9Cab7 fR2cqb0BJlAJQJMJOqRsvdO8UxZ+SHcXtRWqbNffQ7kLiES3gq/0KHqRWG3ohFVjwh BxboM1ujg58+y6sF0XSg1BzImFs3wSl3Z0w0MLSc= Date: Fri, 2 Dec 2022 16:50:27 -0800 From: Andrew Morton To: Yosry Ahmed Cc: Shakeel Butt , Roman Gushchin , Johannes Weiner , Michal Hocko , Yu Zhao , Muchun Song , Tejun Heo , "Matthew Wilcox (Oracle)" , Vasily Averin , Vlastimil Babka , Chris Down , David Rientjes , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v3 1/3] mm: memcg: fix stale protection of reclaim target memcg Message-Id: <20221202165027.8d0761724f30f6701a9a5da0@linux-foundation.org> In-Reply-To: References: <20221202031512.1365483-1-yosryahmed@google.com> <20221202031512.1365483-2-yosryahmed@google.com> <20221202163527.a72646c9d42f3678b20dac7b@linux-foundation.org> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Spamd-Result: default: False [2.60 / 9.00]; IRL_BL_25(2.00)[52.25.139.140:received]; MV_CASE(0.50)[]; MIME_GOOD(-0.10)[text/plain]; RCVD_NO_TLS_LAST(0.10)[]; BAD_REP_POLICIES(0.10)[]; BAYES_HAM(-0.00)[39.18%]; R_SPF_ALLOW(0.00)[+a:ams.source.kernel.org]; R_DKIM_ALLOW(0.00)[linux-foundation.org:s=korg]; RCPT_COUNT_TWELVE(0.00)[16]; FROM_EQ_ENVFROM(0.00)[]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; TO_DN_SOME(0.00)[]; DKIM_TRACE(0.00)[linux-foundation.org:+]; RCVD_COUNT_THREE(0.00)[3]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_SOME(0.00)[]; DMARC_NA(0.00)[linux-foundation.org]; MID_RHS_MATCH_FROM(0.00)[]; ARC_SIGNED(0.00)[hostedemail.com:s=arc-20220608:i=1]; RCVD_VIA_SMTP_AUTH(0.00)[] X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 9EC0D80002 X-Stat-Signature: s55y8iszejptz84j8q4r5ztdrous3hfu X-HE-Tag: 1670028631-291503 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, 2 Dec 2022 16:38:12 -0800 Yosry Ahmed wrote: > On Fri, Dec 2, 2022 at 4:35 PM Andrew Morton wrote: > > > > On Fri, 2 Dec 2022 16:26:05 -0800 Yosry Ahmed wrote: > > > > > Andrew, does this need to be picked up by stable branches? > > > > Does it? The changelog doesn't have a clear description of the > > user-visible effects of the flaw, which is the guiding light for a > > backport? > > > > > > There are 2 example scenarios in the changelog that misbehave without > this fix, cases where the protection of a memcg that is the target of > reclaim is not ignored as it should be. Yes. I found them quite unclear. How would someone who is experiencing a particualr runtime issue be able to recognize whether this patch might address that issue?