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Mon, 07 Sep 2026 04:25:33 +0000 X-Mizu-Trace-ID: f2e3209ee265622f X-Migadu-Flow: FLOW_OUT From: Ridong Chen To: Steven Rostedt , Masami Hiramatsu , Andrew Morton , Johannes Weiner Cc: Mathieu Desnoyers , David Hildenbrand , Michal Hocko , Qi Zheng , Shakeel Butt , Lorenzo Stoakes , Kairui Song , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-mm@kvack.org, Ridong Chen , Ridong Chen Subject: [PATCH RFC 2/2] mm/mglru: add tracepoint for inc_max_seq Date: Mon, 7 Sep 2026 12:24:47 +0800 Message-Id: <20260907042447.2450663-3-ridong.chen@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260907042447.2450663-1-ridong.chen@linux.dev> References: <20260907042447.2450663-1-ridong.chen@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: wf8xaxeq7ym79jmmzz7bnze8q4a7ey7d X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 6B6C620003 X-Rspam-User: X-HE-Tag: 1788755135-175562 X-HE-Meta: U2FsdGVkX19rnbunyF+68Zg2WKkk+//KTsPxoPiPsMdhAnD8txKpFeql8j/s5JO7VcAlWBb0YSWJm7bsJz6Y2jX9LmwkR2sbs3hOWnhxvsDZnCiSlIS9OxM7a5KLWKNWrZeAGFQCOBlTQGxle0h2gsx/BR1iMoxa5zSH6PYk7L1bBYHHfp1fYJysWXSasdAJ3zhUQPPxuhuvM23Qn9oq9LmQyO37OiuZedrCoHRIqfsukiyV2GACQMjZHtAHymzcNwWv76aVgcSEgdqaNW73HnjC61VBjx+LcWOsl0Mk0w3UU5irJK4MNiVK0aNgvC1bzo3fAu1NlhNdBnX/jnIPhVK0FbkLEmS1loEKOA3FtTL5M5iqK+s342hql7x3u+oxMQr/92z9DmKB4YTa6fk7eDhJHi+6Nj1/C9OhEYoIGlU33frCftdkzIB0cVNhDn8sMSozsIFd++Dy0yDyT3ik3fHiJlQat/58wssk+iT63ocpx5SYfr/dgZOp6zIU5B2A42Gnj4N9ctnzl79vfYJ9JttR5MeVzeaGSwHJT9DjkAndil48Z/x/cL6t08S02HJMZK8L3C5ezc+5t6Uh1YPayal02cLvjH0AfgN6v/hjFFlTNP4ngZACiWTDzv0+HWHeVy5bxu47QVxWsb8W6XJpWRSd632GiUUqXKrQDENJLpTQI6eRA9BQg8At/SsoVgWeMC2h/+pQ92QWud3E2NNGqiGfJHY9Nm5SqMcO2PzFPBC7L6OKpP33S798MU+2RSlvvIztetA2AYv34XdCl5Oj8YBuwmVSqxc4cNt/dKCwWaPqk4J8elFN2ypiwSKocUty7/cAOgyFctE18ekB3OpMkHNcqi4Y+EHbh73ZcgpCEE/xjOm8wvoqwkTLY6iTgZRZgM1DvdUBlP1IasvesquJZgSBVBJIYGNU4WDmtV1z6ArItrf4KKq0kx0uOkrXKXFycQSUVU1vmgRQROyW5hm /TXApHrb BMuZSkqaO4YRZO63jizPMySL3ffkIaLe6hMxKiNHqj9j6EAKNzJLMURRRBoBBrv3VyrDm0GS0Kq/lz0EZSA3+STJnP9u10zHG/w7BzVfWna8N2j/KvOmVnwgwuttPqsn2yb6kytnDe8EKychZZUIJb8un1zAhDzv6c3tKe1eNuPKCSOln+UFNP9cigXtJS3B8rYJk1SOVTzDJsdlmI9AoNWeUElG9+ihE2XLeHanc7SarybeN33ZqcXhW1LVqXrCIofMvHKu9WXg1qytQiZTBZYn0vMw60A9vzMTDVYjs32TIbbY= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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 and the new max_seq alongside the anon and file min_seq. Paired with the mm_mglru_isolate_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 --- include/trace/events/vmscan.h | 30 ++++++++++++++++++++++++++++++ mm/vmscan.c | 4 ++++ 2 files changed, 34 insertions(+) diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h index a0e3cf75294b..ab93c2f4b318 100644 --- a/include/trace/events/vmscan.h +++ b/include/trace/events/vmscan.h @@ -439,6 +439,36 @@ TRACE_EVENT(mm_mglru_isolate_folios, __entry->max_seq) ); +TRACE_EVENT(mm_mglru_inc_max_seq, + + TP_PROTO(u64 memcg_id, + unsigned long max_seq, + unsigned long anon_min_seq, + unsigned long file_min_seq), + + TP_ARGS(memcg_id, max_seq, anon_min_seq, file_min_seq), + + TP_STRUCT__entry( + __field(u64, memcg_id) + __field(unsigned long, max_seq) + __field(unsigned long, anon_min_seq) + __field(unsigned long, file_min_seq) + ), + + TP_fast_assign( + __entry->memcg_id = memcg_id; + __entry->max_seq = max_seq; + __entry->anon_min_seq = anon_min_seq; + __entry->file_min_seq = file_min_seq; + ), + + TP_printk("memcg_id=%llu max_seq=%lu anon_min_seq=%lu file_min_seq=%lu", + __entry->memcg_id, + __entry->max_seq, + __entry->anon_min_seq, + __entry->file_min_seq) +); + TRACE_EVENT(mm_vmscan_write_folio, TP_PROTO(struct folio *folio), diff --git a/mm/vmscan.c b/mm/vmscan.c index 771fe6827939..3c806a57d113 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4065,6 +4065,10 @@ static bool inc_max_seq(struct lruvec *lruvec, unsigned long seq, int swappiness WRITE_ONCE(lrugen->timestamps[next], jiffies); /* make sure preceding modifications appear */ smp_store_release(&lrugen->max_seq, lrugen->max_seq + 1); + trace_mm_mglru_inc_max_seq(mem_cgroup_id(lruvec_memcg(lruvec)), + lrugen->max_seq, + lrugen->min_seq[LRU_GEN_ANON], + lrugen->min_seq[LRU_GEN_FILE]); unlock: lruvec_unlock_irq(lruvec); -- 2.34.1