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Received: from 30.74.144.134(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0XAsfnHs_1789371480 cluster:ay36) by smtp.aliyun-inc.com; Mon, 14 Sep 2026 15:38:01 +0800 Message-ID: <8e3147dd-0ef5-486c-b635-a34bd29b25e3@linux.alibaba.com> Date: Mon, 14 Sep 2026 15:38:00 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 3/3] mm/mglru: add tracepoint for inc_max_seq() To: Ridong Chen , Steven Rostedt , Masami Hiramatsu , Andrew Morton , Johannes Weiner Cc: Mathieu Desnoyers , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , David Hildenbrand , Michal Hocko , Lorenzo Stoakes , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, "open list:MEMORY MANAGEMENT - MGLRU (MULTI-GEN LRU)" , Ridong Chen References: <20260911102939.2485750-1-ridong.chen@linux.dev> <20260911102939.2485750-4-ridong.chen@linux.dev> From: Baolin Wang In-Reply-To: <20260911102939.2485750-4-ridong.chen@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 04283120009 X-Stat-Signature: 4dq1ckgnsx94y4eug1drpdwug8qqxwxj X-Rspam-User: X-HE-Tag: 1789371485-664414 X-HE-Meta: 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 yvyJQGhZ b02HCHRT/aRmT0kJmumiCsO9Ea6MbDtxPtjQpOrGBDA7YDBK6LVriG+iM9HTQagyuWXtAfH1VjSH1wd+7hjIRD4LRiQDVRvxVBrmUncVJ6O34DnxY0KvTJalf3b5zfshKKgZCrnZGX59rNMrlTnSwktI7wTxSDnkwCjdIKS+rdOM1Yd6w5WDDJGg+KGAMXyFvRQOB7F8iX73BBJxQSy3aZrSBsDStpNJx+pMXWRdO3vHOFlFqQSFGHeNYyt6ckZQqIBzG+bkxpc4JcD3Uh3ep50Tqsyt4uGttFRZ09FISaCSjzVOIswFF5RWgV7JMNouwPq31JoioCQekGvgZ4N0LqbL43/FT9Hq6C2Tppshb6c8lX4Ttwxo2+1tDPQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/11/26 6:29 PM, Ridong Chen wrote: > From: Ridong Chen > > Aging in MGLRU advances max_seq via inc_max_seq(), creating a new > youngest generation. There is currently no tracepoint on this path, so > the moment a new generation is created, and how the min_seq of each type > trails behind it, cannot be observed as it happens. > > Add mm_mglru_inc_max_seq, emitted right after max_seq is bumped, with > the memcg id, the new max_seq, the anon and file min_seq, and the number > of pages in each generation for both types, summed over zones the same > way the debugfs lru_gen file reports them. The nr_anon/nr_file arrays are > indexed by generation slot, so the emitted max_seq/min_seq say which slot > holds which seq. They are printed with __print_array(), so the output is > hex and its length follows MAX_NR_GENS automatically. Paired with the > mm_mglru_scan_folios tracepoint it makes the full aging-to-eviction > window observable per memcg. > > Assisted-by: Claude:claude-opus-4-8 > Signed-off-by: Ridong Chen > --- Make sense to me. Reviewed-by: Baolin Wang