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b=Gw9tp26MMyOVgrjcdB+C0EAELXC4QV74eJCsDZmFjl33CPFSAdNdq1SRi3khUNlOe gNNpZdmA2RpLLD3oZlJW5pDgM5JeFwr5WCYBO9uCtQ0p5llV5xoiPI4HpjnvwTAkCp Dgccek7ekrc+CLtgbRRtk7Ebc7mKpRxOYGWsio/A= Date: Mon, 24 Jun 2024 14:26:54 -0700 From: Andrew Morton To: Kairui Song Cc: Kairui Song , 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" Subject: Re: [PATCH 0/7] Split list_lru lock into per-cgroup scope Message-Id: <20240624142654.7b7aa167b8fa61fb805a732e@linux-foundation.org> In-Reply-To: <20240624175313.47329-1-ryncsn@gmail.com> References: <20240624175313.47329-1-ryncsn@gmail.com> 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: rspam01 X-Rspamd-Queue-Id: A0C981A0004 X-Stat-Signature: 1a4kk9f6sk5wdb6yff5bwernkhoi1d43 X-HE-Tag: 1719264420-94323 X-HE-Meta: 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 VJjH8XDj 2J95IVztVJBv58rPKJcwAQLUO5U0Zmb5o5d8puV8LgvEt1GCxFEJgXCO6xkswAgfTxKjwnZom+LxIi/PJ1Gv5cH1S2HyvgPkqzRdh+RrNRNpFLRvYSkm39jxBwhHGGuPLNY9Z9heXODFjtvLAvFXXxkp+6sWNjk4Z1kdyPu7iH2UlfgPVeFq4t+b0k72MvAWmqGQDwGY/anCwvny7tjapian4t1fGuJJn1tmOmdJcU6tzZn5bb8PKp2UOLNsKRm8YIT73cQvbf0r/eOPtoV2+IPjJBexx0EJbfMGnP10W+u7TxLg= 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, 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? Anyway, opinions are sought and I'd ask people to please review this work promptly if they feel is it sufficiently beneficial.