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Wong" , Christoph Lameter , David Rientjes , Joonsoo Kim , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, "Matthew Wilcox (Oracle)" , Miaohe Lin , David Hildenbrand , Johannes Weiner , Peter Xu , NeilBrown , Shakeel Butt , Michal Hocko , Yu Zhao , Dave Chinner , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v4 0/3] Ignore non-LRU-based reclaim in memcg reclaim Message-Id: <20230404153124.b0fa5074cf9fc3b9925e8000@linux-foundation.org> In-Reply-To: <20230404152816.cec6d41bfb9de4680ae8c787@linux-foundation.org> References: <20230404001353.468224-1-yosryahmed@google.com> <20230404143824.a8c57452f04929da225a17d0@linux-foundation.org> <20230404145830.b34afedb427921de2f0e2426@linux-foundation.org> <20230404152816.cec6d41bfb9de4680ae8c787@linux-foundation.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: E26E34001D X-Stat-Signature: 553okj1qiqi6i5k4j6a5dx8pjypombdb X-HE-Tag: 1680647487-770346 X-HE-Meta: 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 YU+9hVMM 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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 Tue, 4 Apr 2023 15:28:16 -0700 Andrew Morton wrote: > On Tue, 4 Apr 2023 15:00:57 -0700 Yosry Ahmed wrote: > > > ... > > > > > > > > > > Without refactoring the code that adds reclaim_state->reclaimed to > > > > scan_control->nr_reclaimed into a helper (flush_reclaim_state()), the > > > > change would need to be done in two places instead of one, and I > > > > wouldn't know where to put the huge comment. > > > > > > Well, all depends on how desirable it it that we backport. If "not > > > desirable" then leave things as-is. If at least "possibly desirable" > > > then a simple patch with the two changes and no elaborate comment will > > > suit. > > > > > > > I would rather leave the current series as-is with an elaborate > > comment. I can send a separate single patch as a backport to stable if > > this is something that we usually do (though I am not sure how to > > format such patch). > > -stable maintainers prefer to take something which has already been > accepted by Linus. > > The series could be as simple as > > simple-two-liner.patch > revert-simple-two-liner.patch > this-series-as-is.patch > > simple-two-liner.patch goes into 6.3-rcX and -stable. The other > patches into 6.4-rc1. But the key question remains: how desirable is a backport? Looking at the changelogs I'm not seeing a clear statement of the impact upon real-world users' real-world workloads. (This is a hint). So I am unable to judge. Please share your thoughts on this.