From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9A6E235F60A; Fri, 11 Sep 2026 14:10:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789135811; cv=none; b=ZpmSQW46RoWsEVK/+8J6MyEYOSCUwz+FCtS+H2qXheRuHMRZVZy+nyttXcu7aeZ3ZIAqZYaZgUHLUVNhvSMyo0KFokx0s6MCqUTb2TgBhQjMsuk17zeIpwmDMfQWlkjnAVsjW7dzu6d/lAEDYPqxLSxdfrdKqlAS68NW8OcR6lE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789135811; c=relaxed/simple; bh=hZ9xzrt4yyeD9cnR2YBm71XlWbyTcuBCsTUisFq7y8Q=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=e3DQxUmU/3K8qMaq2BTkDtt3JOCn98U4HHkthP2dJ9r3A2kscGllD1NMSpicEin2U4/+SP+vFdc5bduD306UfqOCvCD+0jsJMcDBfKc4LTm1SHID/SAJKqLHO9qhJsOYJ1ZXT3O2cJNZFqhMawIzGWb8TOJeSb5vv7Yr0IFryZA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; dkim=pass (1024-bit key) header.d=goodmis.org header.i=@goodmis.org header.b=Y2VxROuq; arc=none smtp.client-ip=216.40.44.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=goodmis.org header.i=@goodmis.org header.b="Y2VxROuq" 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; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: z4qikr9ze6ijf13jt3i4esh36hxubsui X-Rspamd-Server: rspamout08 X-Rspamd-Queue-Id: 7288820028 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX19T0oTOyvjgt5li9uFXcMUJERRsN76FEGY= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=goodmis.org; h=date:from:to:cc:subject:message-id:in-reply-to:references:mime-version:content-type:content-transfer-encoding; s=dkim1; bh=mNBI0OlIe4nzIdsfwzVCeMqFH4qZxaPBgm0tmhtgZaE=; b=Y2VxROuqMdZ4zfgK9/f6AKrfKHXGoeUDmeQv85XnbiZZQOMTF84x1FM/RTeVyxo4c567bHvNLMv8fTaprArehqeBQaXu9+F3Fwb7c2U9XoNA2SABG8sRvSLIVDKgnIixjSDjNqUuEvsMg+yDH0sL5ZDc4JhdSUkDNxS7ijgRmm4= X-HE-Tag: 1789135799-473225 X-HE-Meta: U2FsdGVkX1+EGFXRnXr/J3wqoz/KqkpAHbA33YbqajygCWkhwg0wfXJt4aZhAuaXRBNKSnOvt5Z3reG4g4wu6PCXgzdWSCgHqVcFVkESUfxoMO/77XBjhN99o1EqRO41WYpphK4aOzeD0N1FBkMjLmsBujhRKUu/j4e/7ZyF7tAFOB+E5VfYDkQQ7ywkxfGmY11K29qi83HDWYmpUgikZxAp408wyXkvXPXELwZXt2ND5qHAPSv4zy2c8iVVDfodX1h/OMI5ap/AS19+U1ehwrEg+EO8tBTvAO3Bqn+HsYG9dTSgMQb1FqtrqWMTU9l0 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) 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; > --