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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5E9DC54FCB for ; Thu, 23 Apr 2020 23:10:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A126F20780 for ; Thu, 23 Apr 2020 23:10:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587683417; bh=igt1K/a1ZMxJiTPpRElNSn87vNdw8wzrU/2oEcIWO+I=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=szqu5enmuUbc8btLeZuWBPs1GHMQuJUkf49dQnqnjol1m6flUmSkQccnzIOnX/uLh 03NVxehOgDspUmHtH9xu1M6Q1WVqApXwjU53LDTACyLzOKFvQ0KuyXiMTibvJpR2k2 T1rrDdTHih2Hh4jfV/3MEOYje7mvFYPidKxCsZ8s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729150AbgDWXKQ (ORCPT ); Thu, 23 Apr 2020 19:10:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:45836 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729126AbgDWXKL (ORCPT ); Thu, 23 Apr 2020 19:10:11 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 75C9C20784; Thu, 23 Apr 2020 23:10:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587683410; bh=igt1K/a1ZMxJiTPpRElNSn87vNdw8wzrU/2oEcIWO+I=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=zJjycQhOOkbHFuEq2ic7HPwLXbL4kcXh8j0YbwEliwqANWjvplYZB3Vc9h24jK6ay 5nBE4e1ZOlWoMaDWMu/AKWNiLLALT5keROykushwTF9e+05WMJFNa3ben3F3qUOE3G x/+i15LpU0m/5eKFhKcitOfYP5J3CXXPmIRgBcP0= Date: Thu, 23 Apr 2020 16:10:09 -0700 From: Andrew Morton To: Shakeel Butt Cc: Johannes Weiner , Roman Gushchin , Michal Hocko , Linux MM , Cgroups , LKML Subject: Re: [PATCH] memcg: optimize memory.numa_stat like memory.stat Message-Id: <20200423161009.973c645420a4d17ded2a67ee@linux-foundation.org> In-Reply-To: References: <20200304022058.248270-1-shakeelb@google.com> <20200305204109.be23f5053e2368d3b8ccaa06@linux-foundation.org> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 23 Apr 2020 15:59:41 -0700 Shakeel Butt wrote: > > > text data bss dec hex filename > > > now: 106705 35641 1024 143370 2300a mm/memcontrol.o > > > shakeel: 107111 35657 1024 143792 231b0 mm/memcontrol.o > > > shakeel+the-above: 106805 35657 1024 143486 2307e mm/memcontrol.o > > > > > > Which do we prefer? The 100-byte patch or the 406-byte patch? > > > > I would go with the 100-byte one. The for-loop is just 5 iteration, so > > doing a check in each iteration should not be an issue. > > > > Andrew, anything more needed for this patch to be merged? Some feedback from hannes & mhocko would be appreciated? From: Shakeel Butt Subject: mm/memcg: optimize memory.numa_stat like memory.stat Currently reading memory.numa_stat traverses the underlying memcg tree multiple times to accumulate the stats to present the hierarchical view of the memcg tree. However the kernel already maintains the hierarchical view of the stats and use it in memory.stat. Just use the same mechanism in memory.numa_stat as well. I ran a simple benchmark which reads root_mem_cgroup's memory.numa_stat file in the presense of 10000 memcgs. The results are: Without the patch: $ time cat /dev/cgroup/memory/memory.numa_stat > /dev/null real 0m0.700s user 0m0.001s sys 0m0.697s With the patch: $ time cat /dev/cgroup/memory/memory.numa_stat > /dev/null real 0m0.001s user 0m0.001s sys 0m0.000s [akpm@linux-foundation.org: avoid forcing out-of-line code generation] Link: http://lkml.kernel.org/r/20200304022058.248270-1-shakeelb@google.com Signed-off-by: Shakeel Butt Reviewed-by: Andrew Morton Cc: Johannes Weiner Cc: Roman Gushchin Cc: Michal Hocko Signed-off-by: Andrew Morton --- mm/memcontrol.c | 49 +++++++++++++++++++++++----------------------- 1 file changed, 25 insertions(+), 24 deletions(-) --- a/mm/memcontrol.c~memcg-optimize-memorynuma_stat-like-memorystat +++ a/mm/memcontrol.c @@ -3688,7 +3688,7 @@ static int mem_cgroup_move_charge_write( #define LRU_ALL ((1 << NR_LRU_LISTS) - 1) static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, - int nid, unsigned int lru_mask) + int nid, unsigned int lru_mask, bool tree) { struct lruvec *lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid)); unsigned long nr = 0; @@ -3699,13 +3699,17 @@ static unsigned long mem_cgroup_node_nr_ for_each_lru(lru) { if (!(BIT(lru) & lru_mask)) continue; - nr += lruvec_page_state_local(lruvec, NR_LRU_BASE + lru); + if (tree) + nr += lruvec_page_state(lruvec, NR_LRU_BASE + lru); + else + nr += lruvec_page_state_local(lruvec, NR_LRU_BASE + lru); } return nr; } static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg, - unsigned int lru_mask) + unsigned int lru_mask, + bool tree) { unsigned long nr = 0; enum lru_list lru; @@ -3713,7 +3717,10 @@ static unsigned long mem_cgroup_nr_lru_p for_each_lru(lru) { if (!(BIT(lru) & lru_mask)) continue; - nr += memcg_page_state_local(memcg, NR_LRU_BASE + lru); + if (tree) + nr += memcg_page_state(memcg, NR_LRU_BASE + lru); + else + nr += memcg_page_state_local(memcg, NR_LRU_BASE + lru); } return nr; } @@ -3733,34 +3740,28 @@ static int memcg_numa_stat_show(struct s }; const struct numa_stat *stat; int nid; - unsigned long nr; struct mem_cgroup *memcg = mem_cgroup_from_seq(m); for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { - nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask); - seq_printf(m, "%s=%lu", stat->name, nr); - for_each_node_state(nid, N_MEMORY) { - nr = mem_cgroup_node_nr_lru_pages(memcg, nid, - stat->lru_mask); - seq_printf(m, " N%d=%lu", nid, nr); - } + seq_printf(m, "%s=%lu", stat->name, + mem_cgroup_nr_lru_pages(memcg, stat->lru_mask, + false)); + for_each_node_state(nid, N_MEMORY) + seq_printf(m, " N%d=%lu", nid, + mem_cgroup_node_nr_lru_pages(memcg, nid, + stat->lru_mask, false)); seq_putc(m, '\n'); } for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { - struct mem_cgroup *iter; - nr = 0; - for_each_mem_cgroup_tree(iter, memcg) - nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask); - seq_printf(m, "hierarchical_%s=%lu", stat->name, nr); - for_each_node_state(nid, N_MEMORY) { - nr = 0; - for_each_mem_cgroup_tree(iter, memcg) - nr += mem_cgroup_node_nr_lru_pages( - iter, nid, stat->lru_mask); - seq_printf(m, " N%d=%lu", nid, nr); - } + seq_printf(m, "hierarchical_%s=%lu", stat->name, + mem_cgroup_nr_lru_pages(memcg, stat->lru_mask, + true)); + for_each_node_state(nid, N_MEMORY) + seq_printf(m, " N%d=%lu", nid, + mem_cgroup_node_nr_lru_pages(memcg, nid, + stat->lru_mask, true)); seq_putc(m, '\n'); } _