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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3A0EFC433F5 for ; Fri, 5 Nov 2021 20:37:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 23268611C4 for ; Fri, 5 Nov 2021 20:37:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233155AbhKEUkQ (ORCPT ); Fri, 5 Nov 2021 16:40:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:35044 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233038AbhKEUkP (ORCPT ); Fri, 5 Nov 2021 16:40:15 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 24DD161252; Fri, 5 Nov 2021 20:37:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1636144655; bh=MHyJACwCe3CuEGC+Njn6Dps9KgUr3ex5b66zNaCxUbM=; h=Date:From:To:Subject:In-Reply-To:From; b=P7b7U40F+TZIYKwCkm6KH3IMlmqrp79nN2Bdn6IHKby0XiRce+OR4u4lSrKZYDT2/ 2F4RaSA97it4bV5dXD42kt3g8+Xb/I9pShEvQ7/PWUN/7Da5IPyk8q0vAUV+Mfh+96 Vzv0BBuHCCMQ7+TNciG/Ltn6lccHqsOQS0QabpoI= Date: Fri, 05 Nov 2021 13:37:34 -0700 From: Andrew Morton To: akpm@linux-foundation.org, hannes@cmpxchg.org, linux-mm@kvack.org, mhocko@kernel.org, mkoutny@suse.com, mm-commits@vger.kernel.org, shakeelb@google.com, torvalds@linux-foundation.org Subject: [patch 056/262] memcg: unify memcg stat flushing Message-ID: <20211105203734.G_ioCWCJv%akpm@linux-foundation.org> In-Reply-To: <20211105133408.cccbb98b71a77d5e8430aba1@linux-foundation.org> User-Agent: s-nail v14.8.16 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org =46rom: Shakeel Butt Subject: memcg: unify memcg stat flushing The memcg stats can be flushed in multiple context and potentially in parallel too. For example multiple parallel user space readers for memcg stats will contend on the rstat locks with each other. There is no need for that. We just need one flusher and everyone else can benefit. In addition after aa48e47e3906 ("memcg: infrastructure to flush memcg stats") the kernel periodically flush the memcg stats from the root, so, the other flushers will potentially have much less work to do. Link: https://lkml.kernel.org/r/20211001190040.48086-2-shakeelb@google.com Signed-off-by: Shakeel Butt Acked-by: Johannes Weiner Cc: Michal Hocko Cc: "Michal Koutn=C3=BD" Signed-off-by: Andrew Morton --- mm/memcontrol.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) --- a/mm/memcontrol.c~memcg-unify-memcg-stat-flushing +++ a/mm/memcontrol.c @@ -660,12 +660,14 @@ static inline void memcg_rstat_updated(s =20 static void __mem_cgroup_flush_stats(void) { - if (!spin_trylock(&stats_flush_lock)) + unsigned long flag; + + if (!spin_trylock_irqsave(&stats_flush_lock, flag)) return; =20 cgroup_rstat_flush_irqsafe(root_mem_cgroup->css.cgroup); atomic_set(&stats_flush_threshold, 0); - spin_unlock(&stats_flush_lock); + spin_unlock_irqrestore(&stats_flush_lock, flag); } =20 void mem_cgroup_flush_stats(void) @@ -1461,7 +1463,7 @@ static char *memory_stat_format(struct m * * Current memory state: */ - cgroup_rstat_flush(memcg->css.cgroup); + mem_cgroup_flush_stats(); =20 for (i =3D 0; i < ARRAY_SIZE(memory_stats); i++) { u64 size; @@ -3565,8 +3567,7 @@ static unsigned long mem_cgroup_usage(st unsigned long val; =20 if (mem_cgroup_is_root(memcg)) { - /* mem_cgroup_threshold() calls here from irqsafe context */ - cgroup_rstat_flush_irqsafe(memcg->css.cgroup); + mem_cgroup_flush_stats(); val =3D memcg_page_state(memcg, NR_FILE_PAGES) + memcg_page_state(memcg, NR_ANON_MAPPED); if (swap) @@ -3947,7 +3948,7 @@ static int memcg_numa_stat_show(struct s int nid; struct mem_cgroup *memcg =3D mem_cgroup_from_seq(m); =20 - cgroup_rstat_flush(memcg->css.cgroup); + mem_cgroup_flush_stats(); =20 for (stat =3D stats; stat < stats + ARRAY_SIZE(stats); stat++) { seq_printf(m, "%s=3D%lu", stat->name, @@ -4019,7 +4020,7 @@ static int memcg_stat_show(struct seq_fi =20 BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) !=3D ARRAY_SIZE(memcg1_stats)); =20 - cgroup_rstat_flush(memcg->css.cgroup); + mem_cgroup_flush_stats(); =20 for (i =3D 0; i < ARRAY_SIZE(memcg1_stats); i++) { unsigned long nr; @@ -4522,7 +4523,7 @@ void mem_cgroup_wb_stats(struct bdi_writ struct mem_cgroup *memcg =3D mem_cgroup_from_css(wb->memcg_css); struct mem_cgroup *parent; =20 - cgroup_rstat_flush_irqsafe(memcg->css.cgroup); + mem_cgroup_flush_stats(); =20 *pdirty =3D memcg_page_state(memcg, NR_FILE_DIRTY); *pwriteback =3D memcg_page_state(memcg, NR_WRITEBACK); @@ -6405,7 +6406,7 @@ static int memory_numa_stat_show(struct int i; struct mem_cgroup *memcg =3D mem_cgroup_from_seq(m); =20 - cgroup_rstat_flush(memcg->css.cgroup); + mem_cgroup_flush_stats(); =20 for (i =3D 0; i < ARRAY_SIZE(memory_stats); i++) { int nid; _