From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.166 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793437323; b=BviRmxvS4ZW6cd5wIvdShFsgRI5l1A0rarkn6lGfDPau2FYeysMBzMcDwEIzT0n0YUl1 lIZ+X+rt2IQc7YW5yuRr7noU/DlrFUHn4WxeBI9S4tWZq01NDgIxVSbXsdvT/HdeH7zVg 9Q1QjIw3L0PD5eHDXyv8HV1qotm/i5zCNb4gvUBe6reuQb9M+CrnLrIpMCslkq17yGB37 ZA8LKtXoCiJGKcdVGLmqIW/VdbJiNtq5Ywt7LudBvcLaClxu5Ee8fp18HGoSv0Dch0T32 Itq/WxA5ebKSXfYGpSCK3aKaXqcgNbzWGSIwbz+q1RGFBn5ZojusLZOlf1WzswlGDrg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793437323; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:Date:Message-ID: X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=olUAZWb4rGnN0WOUAfDAcNNMoLgDIGZnl5od4gLL/8A=; b=vFRrCg4UdTiuTiBLSXQ311Fv4BkISTezJX2PNtvh+NXbAxVimSi2eAlGcUhGzoW/bFA6 jYxI0BEwaMEJF21vw7BbFPN/hsLJ5vh52Vr7TfpyURxFIgN+J2sp/hF7JM+ELeLRKorP5 yy+C59kI8E5he6MAwl5I3U5/0QFzxh6MarJ4jqp9kNPTKFc9S5z9XhU4cH9Bvpz5foEra rKi65xcnULhXj///IOFVxyNkN3xmgP0cVfbcQz8BJC+NkgnVLgWZvQ3fCyodVX9Iiey14 VYn3kEzE0zDXacahX6XQHTo+a6cQdFxQ3VlM7VRbIhljN/12HBw6vQxgR03VDd4nYzg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=uGbX2OdZ; arc=none smtp.remote-ip=91.218.175.166 Received: from mta0.migadu.com (out-166.mta0.migadu.com [91.218.175.166]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E3B0E606A324 for ; Sat, 31 Oct 2026 09:02:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org E3B0E606A324 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=uGbX2OdZ X-Envelope-To: bpf@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=7oaQzh3qIYdYljiSohYitxTlhwMYY+sEAEK75MIPRFw=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793437320; v=1; x=1794042120; b=uGbX2OdZDDvuT9QNY7AfoBgt6rUlIIG5PSNdObeHyALrAP1okGgWz4f4p4tTlFqHUVD9j1ZG WNLlsgtgdqhG2FdFDIK/q1pbYHcHJt4dC+IeeW8D2XxgOoScxqh4x1OtVzHYOKDlGLCVUo/J4NZ bShoJ8QG63/QOTYhq/BftB7w= X-Envelope-To: bpf@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id bda5cc6f278b6035; Sat, 31 Oct 2026 09:02:00 +0000 X-Mizu-Trace-ID: bda5cc6f278b6035 X-Migadu-Flow: FLOW_OUT From: Ridong Chen To: Steven Rostedt , Masami Hiramatsu , Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Dave Chinner Cc: Mathieu Desnoyers , Muchun Song , Qi Zheng , Kairui Song , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , David Hildenbrand , Lorenzo Stoakes , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org (open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)), bpf@vger.kernel.org (open list:BPF [MISC]:Keyword:(?:\b|_)bpf(?:\b|_)), Ridong Chen , Ridong Chen Subject: [PATCH v5 6/6] mm/mglru: add tracepoint for inc_max_seq() Date: Sat, 31 Oct 2026 17:00:41 +0800 Message-ID: <20261031090041.58574-7-ridong.chen@linux.dev> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20261031090041.58574-1-ridong.chen@linux.dev> References: <20261031090041.58574-1-ridong.chen@linux.dev> X-Mailing-List: bpf@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 while the lruvec lock is still held, with the node id, 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 and clamped to >= 0 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. Only the lruvec is passed in; all of the above is collected in TP_fast_assign(), so inc_max_seq() does no extra work when the event is disabled. Paired with mm_mglru_scan_folios it makes the full aging-to-eviction window observable per memcg. Signed-off-by: Ridong Chen --- mm/trace_vmscan.h | 47 +++++++++++++++++++++++++++++++++++++++++++++++ mm/vmscan.c | 2 ++ 2 files changed, 49 insertions(+) diff --git a/mm/trace_vmscan.h b/mm/trace_vmscan.h index 8148b8224422..cddf42b5849a 100644 --- a/mm/trace_vmscan.h +++ b/mm/trace_vmscan.h @@ -456,6 +456,53 @@ TRACE_EVENT(mm_mglru_scan_folios, __entry->min_seq) ); +TRACE_EVENT(mm_mglru_inc_max_seq, + + TP_PROTO(struct lruvec *lruvec), + + TP_ARGS(lruvec), + + TP_STRUCT__entry( + __field(u64, memcg_id) + __field(unsigned long, max_seq) + __field(unsigned long, anon_min_seq) + __field(unsigned long, file_min_seq) + __array(unsigned long, nr_anon, MAX_NR_GENS) + __array(unsigned long, nr_file, MAX_NR_GENS) + __field(int, nid) + ), + + TP_fast_assign( + struct lru_gen_folio *lrugen = &lruvec->lrugen; + int gen, zone; + + __entry->memcg_id = mem_cgroup_id(lruvec_memcg(lruvec)); + __entry->max_seq = lrugen->max_seq; + __entry->anon_min_seq = lrugen->min_seq[LRU_GEN_ANON]; + __entry->file_min_seq = lrugen->min_seq[LRU_GEN_FILE]; + /* summed over zones and clamped to >= 0, as debugfs lru_gen does */ + for (gen = 0; gen < MAX_NR_GENS; gen++) { + __entry->nr_anon[gen] = 0; + __entry->nr_file[gen] = 0; + for (zone = 0; zone < MAX_NR_ZONES; zone++) { + __entry->nr_anon[gen] += + max(lrugen->nr_pages[gen][LRU_GEN_ANON][zone], 0L); + __entry->nr_file[gen] += + max(lrugen->nr_pages[gen][LRU_GEN_FILE][zone], 0L); + } + } + __entry->nid = lruvec_pgdat(lruvec)->node_id; + ), + + TP_printk("nid=%d memcg_id=%llu max_seq=%lu anon_min_seq=%lu file_min_seq=%lu nr_anon=%s nr_file=%s", + __entry->nid, + __entry->memcg_id, + __entry->max_seq, + __entry->anon_min_seq, + __entry->file_min_seq, + __print_array(__entry->nr_anon, MAX_NR_GENS, sizeof(unsigned long)), + __print_array(__entry->nr_file, MAX_NR_GENS, sizeof(unsigned long))) +); #endif /* CONFIG_LRU_GEN */ TRACE_EVENT(mm_vmscan_write_folio, diff --git a/mm/vmscan.c b/mm/vmscan.c index ff51fee872f8..24cb2b7779b1 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4134,6 +4134,8 @@ 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(lruvec); unlock: lruvec_unlock_irq(lruvec); -- 2.43.0