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=-15.7 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_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 EE5EEC433FE for ; Mon, 7 Dec 2020 12:36:10 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5F63D233EE for ; Mon, 7 Dec 2020 12:36:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5F63D233EE Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id AAEC08D0007; Mon, 7 Dec 2020 07:36:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A5E978D0001; Mon, 7 Dec 2020 07:36:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 99CCD8D0007; Mon, 7 Dec 2020 07:36:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0233.hostedemail.com [216.40.44.233]) by kanga.kvack.org (Postfix) with ESMTP id 83FCC8D0001 for ; Mon, 7 Dec 2020 07:36:09 -0500 (EST) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 473C8362B for ; Mon, 7 Dec 2020 12:36:09 +0000 (UTC) X-FDA: 77566433658.26.view51_5405c84273de Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin26.hostedemail.com (Postfix) with ESMTP id 2604C1804B661 for ; Mon, 7 Dec 2020 12:36:09 +0000 (UTC) X-HE-Tag: view51_5405c84273de X-Filterd-Recvd-Size: 3703 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Mon, 7 Dec 2020 12:36:08 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1607344567; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=rvs081RAGQPaFquBIFuFiPgtjv7glx+tVrBE85otOnw=; b=Eugiw6R2M3d1tGTGOVHNaxSZUo0OJvOH6z4OoBj3eg9W37zRl8JNEYrEQaCdQg7pgiLFRr 3nm+3Dm6QgbPfpeXJZBLKD6S3UW6dUUENnu9me6G8pZOi6kOP8DXosWxYHw1VwuKdpS+TB 3MJU7FKpT3t/nNHLNSZjswHItP6saVc= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 63CDFAC9A; Mon, 7 Dec 2020 12:36:07 +0000 (UTC) Date: Mon, 7 Dec 2020 13:36:05 +0100 From: Michal Hocko To: Muchun Song Cc: hannes@cmpxchg.org, vdavydov.dev@gmail.com, akpm@linux-foundation.org, shakeelb@google.com, guro@fb.com, sfr@canb.auug.org.au, alexander.h.duyck@linux.intel.com, chris@chrisdown.name, laoar.shao@gmail.com, richard.weiyang@gmail.com, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm: memcontrol: optimize per-lruvec stats counter memory usage Message-ID: <20201207123605.GH25569@dhcp22.suse.cz> References: <20201206085639.12627-1-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201206085639.12627-1-songmuchun@bytedance.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sun 06-12-20 16:56:39, Muchun Song wrote: > The vmstat threshold is 32 (MEMCG_CHARGE_BATCH), so the type of s32 > of lruvec_stat_cpu is enough. And introduce struct per_cpu_lruvec_stat > to optimize memory usage. How much savings are we talking about here? I am not deeply familiar with the pcp allocator but can it compact smaller data types much better? > Signed-off-by: Muchun Song > --- > include/linux/memcontrol.h | 6 +++++- > mm/memcontrol.c | 2 +- > 2 files changed, 6 insertions(+), 2 deletions(-) > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index f9a496c4eac7..34cf119976b1 100644 > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -92,6 +92,10 @@ struct lruvec_stat { > long count[NR_VM_NODE_STAT_ITEMS]; > }; > > +struct per_cpu_lruvec_stat { > + s32 count[NR_VM_NODE_STAT_ITEMS]; > +}; > + > /* > * Bitmap of shrinker::id corresponding to memcg-aware shrinkers, > * which have elements charged to this memcg. > @@ -111,7 +115,7 @@ struct mem_cgroup_per_node { > struct lruvec_stat __percpu *lruvec_stat_local; > > /* Subtree VM stats (batched updates) */ > - struct lruvec_stat __percpu *lruvec_stat_cpu; > + struct per_cpu_lruvec_stat __percpu *lruvec_stat_cpu; > atomic_long_t lruvec_stat[NR_VM_NODE_STAT_ITEMS]; > > unsigned long lru_zone_size[MAX_NR_ZONES][NR_LRU_LISTS]; > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 49fbcf003bf5..c874ea37b05d 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -5184,7 +5184,7 @@ static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node) > return 1; > } > > - pn->lruvec_stat_cpu = alloc_percpu_gfp(struct lruvec_stat, > + pn->lruvec_stat_cpu = alloc_percpu_gfp(struct per_cpu_lruvec_stat, > GFP_KERNEL_ACCOUNT); > if (!pn->lruvec_stat_cpu) { > free_percpu(pn->lruvec_stat_local); > -- > 2.11.0 -- Michal Hocko SUSE Labs