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Mon, 02 Nov 2026 01:44:57 +0000 X-Mizu-Trace-ID: 672eb1f5ae80b659 X-Migadu-Flow: FLOW_OUT Date: Mon, 2 Nov 2026 09:44:53 +0800 From: Baoquan He To: Ridong Chen Cc: Steven Rostedt , Masami Hiramatsu , Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Dave Chinner , Mathieu Desnoyers , Muchun Song , Qi Zheng , Kairui Song , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baolin Wang , David Hildenbrand , Lorenzo Stoakes , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-mm@kvack.org, "open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)" , "open list:BPF [MISC]:Keyword:(?:b|_)bpf(?:b|_)" , Ridong Chen Subject: Re: [PATCH v5 5/6] mm/mglru: add tracepoint for scan_folios() Message-ID: References: <20261031090041.58574-1-ridong.chen@linux.dev> <20261031090041.58574-6-ridong.chen@linux.dev> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261031090041.58574-6-ridong.chen@linux.dev> X-Stat-Signature: yuiqi898xawxnik9dtk9b69gzekho9w8 X-Rspamd-Queue-Id: D79421C0006 X-Rspam-User: X-Rspamd-Server: rspam12 X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-HE-Tag: 1793583898-452371 X-HE-Meta: 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 A6q1Qp0b psUgjfZXJyjv2ua8HEj7n0MEf9E1Uh7rr+zLvKogcleF0v1Llk1crhWXgSHQwXxezPKB/U5uSXWRuJSPjo6CV+74hAT82sOilfC+X0H0YFv+8GesncblkYqgsrpsYv4nvNzi5TeD/aZ7IUBj4J1A8Powpr1+hJ4afStCYz5AqeJ4z7QJ0QfbFfAn6u4AgZamsA7Zzr3dJWVwKhJKsInqUW7OW4fhrEywB1ExwWdSMSbhVO51SS1Nk2N8X3Ah5H+mJ0+XQFtSonjhgxaONZ5VelgGh0h9cYUja8BXQfn0getknK4I5BxiiKtbWxzVOoFPTRUEnPhSty8Rs9AhKjgNEdU9AV0vReY5PBXAL1f7QMTpWAR07yfTFy4kEDNqe0bvSFTYYqiN76Rd/pkfxSNq7jCbtACowMoqQTLfy6SIiuRxVwTfURTR6BiqTZLu//GsGsLkS Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 10/31/26 at 05:00pm, Ridong Chen wrote: > From: Ridong Chen > > MGLRU's scan_folios() emits the classic-LRU tracepoint > trace_mm_vmscan_lru_isolate(), which predates MGLRU. It reports the > scan/isolate counts and the LRU type, but carries no generation or > memcg context, so a trace of an MGLRU run cannot tell which memcg a > given scan belongs to, nor how far reclaim has progressed through the > generations. > > Add mm_mglru_scan_folios next to it, reporting the same counters plus > nr_sorted (folios moved to a younger generation by sort_folio()) and > the context the classic tracepoint lacks: the node id and memcg id of > the lruvec, and the max_seq, tier and min_seq of the type being > scanned. > > Now that struct scan_control is visible to the trace header, pass sc, > lruvec, type and tier straight in and derive everything else in > TP_fast_assign(), so nothing is computed at the call site when the > event is disabled. The int fields are grouped at the end of the entry > to avoid padding on 64-bit. > > scan_folios() is the MGLRU-specific layer where folios are actually > scanned, so it has no classic-LRU counterpart. The existing tracepoint > is left unchanged. > > Signed-off-by: Ridong Chen > --- > mm/trace_vmscan.h | 66 +++++++++++++++++++++++++++++++++++++++++++++++ > mm/vmscan.c | 2 ++ > 2 files changed, 68 insertions(+) > > diff --git a/mm/trace_vmscan.h b/mm/trace_vmscan.h > index b2ad83e5f25e..8148b8224422 100644 > --- a/mm/trace_vmscan.h > +++ b/mm/trace_vmscan.h > @@ -392,6 +392,72 @@ TRACE_EVENT(mm_vmscan_lru_isolate, > __print_symbolic(__entry->lru, LRU_NAMES)) > ); > > +#ifdef CONFIG_LRU_GEN > +TRACE_EVENT(mm_mglru_scan_folios, > + > + TP_PROTO(struct lruvec *lruvec, > + struct scan_control *sc, > + unsigned long nr_requested, > + unsigned long nr_scanned, > + unsigned long nr_sorted, > + unsigned long nr_skipped, > + unsigned long nr_taken, > + int type, > + int tier), > + > + TP_ARGS(lruvec, sc, nr_requested, nr_scanned, nr_sorted, nr_skipped, > + nr_taken, type, tier), > + > + TP_STRUCT__entry( > + __field(u64, memcg_id) > + __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, nid) Now it has nid printed out, it's cool. This patch looks good to me, thanks. Reviewed-by: Baoquan He > + __field(int, highest_zoneidx) > + __field(int, order) > + __field(int, lru) > + __field(int, tier) > + ), > + > + TP_fast_assign( > + __entry->memcg_id = mem_cgroup_id(lruvec_memcg(lruvec)); > + __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->max_seq = lruvec->lrugen.max_seq; > + __entry->min_seq = lruvec->lrugen.min_seq[type]; > + __entry->nid = lruvec_pgdat(lruvec)->node_id; > + __entry->highest_zoneidx = sc->reclaim_idx; > + __entry->order = sc->order; > + __entry->lru = type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON; > + __entry->tier = tier; > + ), > + > + TP_printk("nid=%d 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->nid, > + __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) > +); > + > +#endif /* CONFIG_LRU_GEN */ > + > TRACE_EVENT(mm_vmscan_write_folio, > > TP_PROTO(struct folio *folio), > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 15e9184a580a..ff51fee872f8 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -4852,6 +4852,8 @@ static int scan_folios(unsigned long nr_to_scan, struct lruvec *lruvec, > trace_mm_vmscan_lru_isolate(sc, nr_to_scan, > scanned, skipped, isolated, > type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON); > + trace_mm_mglru_scan_folios(lruvec, sc, nr_to_scan, scanned, sorted, > + skipped, isolated, type, tier); > > *isolatedp = isolated; > return scanned; > -- > 2.43.0 >