From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-170.mta0.migadu.com [91.218.175.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7904E3CE4BE for ; Sun, 13 Sep 2026 10:25:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.170 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789295163; cv=none; b=XUk6ypvjTQeeax+yJDA0l7HaXYTH2V/XaZhEbnz0/ZoxIkBCdZZQLaRNLpj93g81qkXR/6sd61Ypea6zt6En1NFxzRcLy/XlUEsX1I4E0r+yy7kba6JXqFQ68MWCvTbtpoU5UJDAP2t4ePXpViDCZ/dC+d7CHPC1IMBga/GLn+E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789295163; c=relaxed/simple; bh=RBRi6I3a87/juJLx+fNqZVRPmjDwMN9oEpqOjLUx424=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=buEGSh9slfTTp8wgU9YPE7TFIWFRVOhgPD/7kZHtlJOMDCnaYnIY+NMb0SzlzqXTXigtntUpHAHJB5MWpJ6eTtsbmKIE6MH7T2WU8QFdQUgoGL5Q95+fnIswkq48YmY/VADY0WaVOTKlUPKwMkvEOal4olcZOekT1iBrzSEOIO0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=w0cdeFZ+; arc=none smtp.client-ip=91.218.175.170 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) header.d=linux.dev header.i=@linux.dev header.b="w0cdeFZ+" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=RBRi6I3a87/juJLx+fNqZVRPmjDwMN9oEpqOjLUx424=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1789295146; v=1; x=1789899946; b=w0cdeFZ+8XOD6hCw74SDPrBrIySEC7wind7pLhSxdkWWliAl+pRJbM1vCWK5X76U1ECD+rDT uYEWCqc889aCXrmQFsHi+y6Q92zdBUEdCQyylKyR5w1AS3xqneCk2t/2cdwCbLuav6LoanJGc7N /z7S46IcHp2uJz7sx8hrzdjo= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 211913a8fa41334d; Sun, 13 Sep 2026 10:25:46 +0000 X-Mizu-Trace-ID: 211913a8fa41334d X-Migadu-Flow: FLOW_OUT Message-ID: Date: Sun, 13 Sep 2026 18:25:38 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/3] mm/mglru: add tracepoint for scan_folios() To: Steven Rostedt Cc: Masami Hiramatsu , Andrew Morton , Johannes Weiner , Mathieu Desnoyers , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , 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: <20260911072848.2346073-1-ridong.chen@linux.dev> <20260911072848.2346073-3-ridong.chen@linux.dev> <20260911101120.25e3495a@gandalf.local.home> From: Ridong Chen In-Reply-To: <20260911101120.25e3495a@gandalf.local.home> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 9/11/2026 10:11 PM, Steven Rostedt wrote: > On Fri, 11 Sep 2026 15:28:47 +0800 > Ridong Chen wrote: > >> diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h >> index 8a872990b4be..c39dfacef033 100644 >> --- a/include/trace/events/vmscan.h >> +++ b/include/trace/events/vmscan.h >> @@ -392,6 +392,69 @@ TRACE_EVENT(mm_vmscan_lru_isolate, >> __print_symbolic(__entry->lru, LRU_NAMES)) >> ); >> >> +TRACE_EVENT(mm_mglru_scan_folios, >> + >> + TP_PROTO(u64 memcg_id, >> + int highest_zoneidx, >> + int order, >> + unsigned long nr_requested, >> + unsigned long nr_scanned, >> + unsigned long nr_sorted, >> + unsigned long nr_skipped, >> + unsigned long nr_taken, >> + int lru, >> + unsigned long max_seq, >> + int tier, >> + unsigned long min_seq), >> + >> + TP_ARGS(memcg_id, highest_zoneidx, order, nr_requested, nr_scanned, >> + nr_sorted, nr_skipped, nr_taken, lru, max_seq, tier, min_seq), >> + >> + TP_STRUCT__entry( >> + __field(u64, memcg_id) >> + __field(int, highest_zoneidx) >> + __field(int, order) >> + __field(unsigned long, nr_requested) >> + __field(unsigned long, nr_scanned) >> + __field(unsigned long, nr_sorted) >> + __field(unsigned long, nr_skipped) >> + __field(unsigned long, nr_taken) >> + __field(int, lru) >> + __field(unsigned long, max_seq) >> + __field(int, tier) >> + __field(unsigned long, min_seq) > Thank you very much for your review. > Please keep "int"s together. This creates a structure that is used to write > into the ring buffer. On 64bit machines, the above would add 4 bytes of > padding after each int, whereas: > > __field(unsigned long, max_seq) > __field(unsigned long, min_seq) > __field(int, lru) > __field(int, tier) > > > would not. > Will upate. >> + ), >> + >> + TP_fast_assign( >> + __entry->memcg_id = memcg_id; >> + __entry->highest_zoneidx = highest_zoneidx; >> + __entry->order = order; >> + __entry->nr_requested = nr_requested; >> + __entry->nr_scanned = nr_scanned; >> + __entry->nr_sorted = nr_sorted; >> + __entry->nr_skipped = nr_skipped; >> + __entry->nr_taken = nr_taken; >> + __entry->lru = lru; >> + __entry->max_seq = max_seq; >> + __entry->tier = tier; >> + __entry->min_seq = min_seq; >> + ), >> + >> + TP_printk("memcg_id=%llu classzone=%d order=%d nr_requested=%lu nr_scanned=%lu nr_sorted=%lu nr_skipped=%lu nr_taken=%lu lru=%s max_seq=%lu tier=%d min_seq=%lu", >> + __entry->memcg_id, >> + __entry->highest_zoneidx, >> + __entry->order, >> + __entry->nr_requested, >> + __entry->nr_scanned, >> + __entry->nr_sorted, >> + __entry->nr_skipped, >> + __entry->nr_taken, >> + __print_symbolic(__entry->lru, LRU_NAMES), >> + __entry->max_seq, >> + __entry->tier, >> + __entry->min_seq) >> +); >> + >> TRACE_EVENT(mm_vmscan_write_folio, >> >> TP_PROTO(struct folio *folio), >> diff --git a/mm/vmscan.c b/mm/vmscan.c >> index 2554a6513aa8..bd1b9ecf2e84 100644 >> --- a/mm/vmscan.c >> +++ b/mm/vmscan.c >> @@ -4876,6 +4876,12 @@ static int scan_folios(unsigned long nr_to_scan, struct lruvec *lruvec, >> trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan, >> scanned, skipped, isolated, >> type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON); >> + trace_mm_mglru_scan_folios(mem_cgroup_id(lruvec_memcg(lruvec)), >> + sc->reclaim_idx, sc->order, nr_to_scan, >> + scanned, sorted, skipped, isolated, >> + type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON, >> + lrugen->max_seq, tier, >> + lrugen->min_seq[type]); > > Can't this information be processed in the tracepoint? That is: > > TP_PROTO(struct lruvec *lruvec, > struct scan_control *sc, > struct lru_gen_folio *lrugen, > unsigned long nr_requested, > unsigned long nr_scanned, > unsigned long nr_sorted, > unsigned long nr_skipped, > unsigned long nr_taken, > int type), > > TP_ARGS(lruvec, sc, lrugen, nr_requested, nr_scanned, > nr_sorted, nr_skipped, nr_taken, type), > > TP_STRUCT__entry( > __field(u64, memcg_id) > __field(int, highest_zoneidx) > __field(int, order) > __field(unsigned long, nr_requested) > __field(unsigned long, nr_scanned) > __field(unsigned long, nr_sorted) > __field(unsigned long, nr_skipped) > __field(unsigned long, nr_taken) > __field(unsigned long, max_seq) > __field(unsigned long, min_seq) > __field(int, lru) > __field(int, tier) > ), > > TP_fast_assign( > __entry->memcg_id = mem_cgroup_id(lruvec_memcg(lruvec)); > __entry->highest_zoneidx = sc->reclaim_idx; > __entry->order = sc->order; > __entry->nr_requested = nr_requested; > __entry->nr_scanned = nr_scanned; > __entry->nr_sorted = nr_sorted; > __entry->nr_skipped = nr_skipped; > __entry->nr_taken = nr_taken; > __entry->lru = type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON; > __entry->max_seq = lrugen->max_seq; > __entry->tier = tier; > __entry->min_seq = lrugen->min_seq; > ), > > > This moves the code to generate the parameters into the TP_fast_assign() > which is in a separate text section. It remove code from the work flow > improving instruction cache. > > Same can be done for that trace_mm_vmscan_lru_isolate() trace event. > Sashiko has reported the same issue, so I updated my series [1] when I received Sashiko's report. Thank you again for pointing this out. [1] https://lore.kernel.org/linux-mm/20260911102939.2485750-3-ridong.chen@linux.dev/ > >> >> *isolatedp = isolated; >> return scanned; >> -- -- Best regards Ridong