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Wed, 04 Nov 2026 01:29:25 +0000 X-Mizu-Trace-ID: 59a6eb213e4c26de X-Migadu-Flow: FLOW_OUT Message-ID: Date: Wed, 4 Nov 2026 09:29:17 +0800 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 7/7] mm/mglru: add tracepoint for inc_max_seq() To: Barry Song Cc: Steven Rostedt , Masami Hiramatsu , Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Dave Chinner , Mathieu Desnoyers , Muchun Song , Qi Zheng , David Hildenbrand , Lorenzo Stoakes , Kairui Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, "open list:BPF [MISC]:Keyword:(?:b|_)bpf(?:b|_)" , Ridong Chen References: <20261103025610.3738894-1-ridong.chen@linux.dev> <20261103025610.3738894-8-ridong.chen@linux.dev> <9cabcddf-d807-4a36-84f1-5bb06ea72aac@linux.dev> From: Ridong Chen In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: DEAF640002 X-Spam-Status: No, score=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=4.0.1 X-Stat-Signature: 5hewfwfzi9z3qexmqjxfdtncgmgnb8bn X-Rspam-User: X-HE-Tag: 1793756249-421477 X-HE-Meta: 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 DE/g90NY KqsSBVwn+fc9fpCqIPsx2mNJY1riQGjFD6ak7hnQ0aQxklZyhMc9K/XXJdPoshsOVjPPRGsex2buHZR/WCJJeH5jo80RPH78VuhEVGfMWrOFZ0e5mq/0mvEzqzp0LJguBRI+6Czm2uFCC8isUFPquCZ01nO3ynGI2LHK6uYOsXIQ7e6jQUCudlxUXB3dIA5J2P/5hs0xRnuZVXf+BIPkSTl1pahw/gcowbXk2xhvZZ9Z9AU2mHPJsyH0oI9WaSCdwMnpE/nI0ryKIRYWgu3KocT1cnblEJsEHB+7DrlBAkyZwEH36kGlbLi2IEZyfPJNTKtLlP14aoexTNv3MJbK2ldsoiYwCH15MuTxb Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 11/4/2026 2:28 AM, Barry Song wrote: > On Tue, Nov 3, 2026 at 8:23 PM Ridong Chen wrote: > [...] >> >> Hi Barry, >> >> Agreed, I'll go with option 2. Two things I'd like to confirm first: >> >> 1) To report the reason, should_run_aging() would need to return it >> instead of a bool, e.g. an enum like: >> >> enum lru_gen_aging_reason { >> AGING_NONE, >> AGING_NO_EVICTABLE, /* eviction is not possible anymore */ >> AGING_MIN_GENS, /* better to age, eviction still possible */ >> }; >> >> Or just report sc->priority, swappiness, max_seq/min_seq and the >> per-generation nr_pages, and let users derive the reason from them? >> The former is more direct, the latter keeps should_run_aging() >> unchanged. > > Right. We can let users infer the reason from max_seq, > min_seq, and nr_pages in each generation. This shouldn't > be difficult, especially since should_run_aging() may > change. We don't need to spell out the exact reason. > Just present users with the overall state of the lru_gen. > >> >> 2) try_to_shrink_lruvec() has changed quite a lot recently, e.g. >> Kairui's reclaim loop rework, and your swappiness series also touches it, >> including the aging part. Is it stable enough now to carry a tracepoint there? >> > > Yes, I think aging will always be needed, regardless of how > we change the code, so this should remain stable. > Thank you for your patience. That makes sense to me. Will update. -- Best regards Ridong