From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.9 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793674683; b=ChWHV/HRZvW7yECpfpoWNbSnc+Xzle8WduNftmukLOc0yDR0Fm3iwiWDm8KWqvt5j5a5 MvZvSJPrhbFRZH5zbYld7SIHVva0QJCyqxx46oF7d5xQjlp91yPN3IYGyPImj0WpuUqH0 KXpceEemSsBrhiWaINuPScmOaf0qNWJK4kLOnZp0NKKKMSjV2aFolct4WF1qd0KOAuh/B djLxNxypwhdnoAYJeFiAFqKc2XI3nCw2tFiooW19B8OZLfD/hD0hVy9nRccB2g9QBut9B 2N8Ya0t6Lhb7Rjbx2m8ScdLwDqX3T4wwUszutNBZ1+izvJjIm1pLGhL95qZX/nii4OA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793674683; 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=4IRpsKB31ZWOQ5n/UsohIDOoT7iKXviBSO161ss/1dE=; b=T1KMVzQZZspms79oBub/N98xzLeRXFmEpBWOaZSi1WaCJxeXXSf/3NMiv89YWe4Yrw/p HGL0Fc4CoHkzyRFHHdr78GeWpiDJ0OGEjbilJVAe6Haxn7YHEJkMLSoQdf9h7Qj4Fk9St b3+bhSHWYvEE1HgvAn4VclSmxDIwpGDIMOM2IXuw4PxTocHBkfpICw8nBfFwXgVKuiAoC YevsQVsWD7RK3a3C02fd/aRRabfgsspgD2fEx5o30trPmbAgRH3nrP92Xxfx7wxcwtt6b ZJSNKny5NOp9WnXmlf0BBDA7h0M4edoTOi0aQdMzWMKD7+Pj4zGpplE4rb65v0rtr2Q== 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=Ymnes9hU; arc=none smtp.remote-ip=91.218.175.9 Received: from mta0.migadu.com (out-9.mta0.migadu.com [91.218.175.9]) (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 7B17C606A324 for ; Tue, 3 Nov 2026 02:58:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 7B17C606A324 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=Ymnes9hU X-Envelope-To: linux-trace-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=lyrb92uDQUPbkiBltZi1bjdhjSGbJYzJNmN2CpAeRBY=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793674680; v=1; x=1794279480; b=Ymnes9hUueYcoUxGz5QwDS5GUw1Qmnr7X/K2zXmtGUWjBAqldu6yJuJArKlNuSWuC36/5Kw5 BCkiEyv5qn7dI9NQNbJMqcVEVyyNlWsdwcoMUU9VOtgUcRweQ7FNGpdbwVe7hR2frOOLJNuqDOu ValsYvN1tCUXXv1UX2u6Uwn8= X-Envelope-To: linux-trace-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 595423ef5b9c1195; Tue, 03 Nov 2026 02:57:59 +0000 X-Mizu-Trace-ID: 595423ef5b9c1195 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 , David Hildenbrand , Lorenzo Stoakes , Kairui Song , Barry 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, bpf@vger.kernel.org (open list:BPF [MISC]:Keyword:(?:\b|_)bpf(?:\b|_)), Ridong Chen , Ridong Chen Subject: [PATCH v6 7/7] mm/mglru: add tracepoint for inc_max_seq() Date: Tue, 3 Nov 2026 10:56:10 +0800 Message-Id: <20261103025610.3738894-8-ridong.chen@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20261103025610.3738894-1-ridong.chen@linux.dev> References: <20261103025610.3738894-1-ridong.chen@linux.dev> X-Mailing-List: linux-trace-kernel@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, as computed by lruvec_gen_size(). The nr_anon/nr_file arrays are ordered by seq rather than by generation slot: entry i holds the generation max_seq - MAX_NR_GENS + 1 + i, i.e. they go from the oldest generation to the newest, the same order as the debugfs lru_gen file, so the output can be read directly without mapping slots back to seqs. Entries for seqs below the corresponding min_seq are not in use and normally read as 0. The arrays 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 | 46 ++++++++++++++++++++++++++++++++++++++++++++++ mm/vmscan.c | 2 ++ 2 files changed, 48 insertions(+) diff --git a/mm/trace_vmscan.h b/mm/trace_vmscan.h index 8148b8224422..40d6d90f1d7a 100644 --- a/mm/trace_vmscan.h +++ b/mm/trace_vmscan.h @@ -456,6 +456,52 @@ 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; + unsigned long max_seq = lrugen->max_seq; + int i; + + __entry->memcg_id = mem_cgroup_id(lruvec_memcg(lruvec)); + __entry->max_seq = max_seq; + __entry->anon_min_seq = lrugen->min_seq[LRU_GEN_ANON]; + __entry->file_min_seq = lrugen->min_seq[LRU_GEN_FILE]; + /* from the oldest generation to the newest, as debugfs lru_gen does */ + for (i = 0; i < MAX_NR_GENS; i++) { + unsigned long seq = max_seq - MAX_NR_GENS + 1 + i; + + __entry->nr_anon[i] = + lruvec_gen_size(lrugen, LRU_GEN_ANON, seq); + __entry->nr_file[i] = + lruvec_gen_size(lrugen, LRU_GEN_FILE, seq); + } + __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 1581b73aec56..841fefa68d1f 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4115,6 +4115,8 @@ 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); -- 2.34.1