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Mon, 27 Apr 2026 06:21:05 +0000 (UTC) Received: from mstore137.sjtu.edu.cn (unknown [10.118.0.137]) by mta90.sjtu.edu.cn (Postfix) with ESMTP id B841737C878; Mon, 27 Apr 2026 14:21:05 +0800 (CST) Date: Mon, 27 Apr 2026 14:21:05 +0800 (CST) From: SUVONOV BUNYOD To: akpm , vbabka@kernel.org, linux-mm Cc: rostedt , mhiramat , mathieu desnoyers , linux-trace-kernel , linux-kernel , surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes , ziy@nvidia.com, david , vishal moola , corbet@lwn.net, skhan@linuxfoundation.org, linux-doc@vger.kernel.org Message-ID: <222049437.2315342.1777270865090.JavaMail.zimbra@sjtu.edu.cn> In-Reply-To: <20260427060142.131055-1-b.suvonov@sjtu.edu.cn> References: <20260425091335.346504-1-b.suvonov@sjtu.edu.cn> <20260427060142.131055-1-b.suvonov@sjtu.edu.cn> Subject: Re: [PATCH v2] mm/page_alloc: trace PCP refills and PCP zone lock usage MIME-Version: 1.0 Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.180.122.86] X-Mailer: Zimbra 10.0.18_GA_4835 (ZimbraWebClient - FF149 (Linux)/10.0.18_GA_4828) Thread-Topic: mm/page_alloc: trace PCP refills and PCP zone lock usage Thread-Index: cvNpGKS1fD456U+LMNaVmpa/8ckf2g== X-Rspam-User: X-Rspamd-Queue-Id: 5350212000F X-Rspamd-Server: rspam06 X-Stat-Signature: 59qbs69ktywbh1np1nsqicuq9f4tdw33 X-HE-Tag: 1777270870-642716 X-HE-Meta: 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 QXGdkOSv 2TYxR8RF2Ni+TrdX12NCq7G/DD1/7uQ6GIVEM/ryoExp+aE4NagcYsbaAJm15ghbu6ZUGH8k3b782myyRYyeF7ySELafwVLMDw+a32dpRa2XGBpLKABYxGcANREfSSR/Lqr+S5DOyvJpwcpwTvz5DXqWa7XNr6BQIQQlwelwJOT2+CkKWZqZTrPVd6AB3m85Ym54U3eWm492eG/M05Ut32UWZ1s6H39zRKxhDwabxpChzhPd3D2rxHzBNI179ZC0P0fJCqzmUePrOqx1UjlZ5PA+6jrhckSKVej1AKkqZaHwRs0Zfqugrd9iwIUy2Q0zUNe+J4/4lpK6v5xTOJxv4ytWHo0GWCUeggf9jLdPSqfCng+/0tlqWhlg1K0xwH7FVJmm14CU2zXfsbxgFdHaK9zYvcXsWvY3wMNMyN2SWK1UBLhecpQAHRCR00bA8XSJ60pdw34pQ3B5lhsvcWbgcsaTdgQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Thank you for reviewing v1 Vishal, All of your concerns except for the last one should be covered in v2. > If you're trying to trace all pages as they come onto the pcp lists, > should you also account for the free_frozen_page_commit() path? > >> } >> spin_unlock_irqrestore(&zone->lock, flags); No, the intent is not to trace every insertion into PCP lists. This patch is trying to make buddy <-> PCP traffic observable by adding a new mm_page_pcpu_refill event symmetric with the existing mm_page_pcpu_drain event. I also added additional zone_locked tracepoints because my research is focusing on analyzing which kernel mm subsystems and other parts are under stress for a given workload. The best way to see it for PCP would be to count zone lock acquirings as the whole purpose of PCP is to lower number of zone lock acquiring in first place.