From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A9668C88E58 for ; Fri, 11 Sep 2026 14:10:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C11326B008C; Fri, 11 Sep 2026 10:10:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BC24A6B0092; Fri, 11 Sep 2026 10:10:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AD8376B0093; Fri, 11 Sep 2026 10:10:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 8960E6B008C for ; Fri, 11 Sep 2026 10:10:08 -0400 (EDT) Received: from smtpin27.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 9F3D6160259 for ; 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b=1WoUPaDEsjieft9V+YNK5gDzTwuLs142thIJWzrt/WrTSI/PKaL2CrO64fm18csNCYRdZ4 q7RDmQTBFioT1xf+Fsp4L1eHdQyIsDNZjFvPOWeSHUNosc8JkS2yLOh4wfjlbHMBMhQ8oR RdoaKP7YKxP/uQsGmU6FVI4ijwIlg+A= Received: from omf08.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 6324E1C1C17; Fri, 11 Sep 2026 14:10:03 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf08.hostedemail.com (Postfix) with ESMTPA id 7288820028; Fri, 11 Sep 2026 14:09:59 +0000 (UTC) Date: Fri, 11 Sep 2026 10:11:20 -0400 From: Steven Rostedt To: Ridong Chen 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, linux-mm@kvack.org (open list:MEMORY MANAGEMENT - MGLRU (MULTI-GEN LRU)), Ridong Chen Subject: Re: [PATCH 2/3] mm/mglru: add tracepoint for scan_folios() Message-ID: <20260911101120.25e3495a@gandalf.local.home> In-Reply-To: <20260911072848.2346073-3-ridong.chen@linux.dev> References: <20260911072848.2346073-1-ridong.chen@linux.dev> <20260911072848.2346073-3-ridong.chen@linux.dev> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; 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> > +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) 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. > + ), > + > + 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. -- Steve > > *isolatedp = isolated; > return scanned; > --