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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 59251C31E5B for ; Mon, 17 Jun 2019 14:38:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2F2E020833 for ; Mon, 17 Jun 2019 14:38:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560782329; bh=GFXJ7vwR3+X5kxZ/7vzEsRZapA2vY/hZ9Ld8rham/bc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=IGEFMcoPPgHAbSfjmhLW/oo8mPzmwiZXTVajGihbvipXM5WiM45HvCRFkAG7O+z2z SlAwfG/GZF0vIC4Fyj1KeSS+WnLp8KN1RFT9F0goW/jOenbfazRtHJ4HGmr83jyb0R U5Qbww6KF5cnlcw7fbkTWitmyVKfZMIbR3RScIZY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728445AbfFQOir (ORCPT ); Mon, 17 Jun 2019 10:38:47 -0400 Received: from mx2.suse.de ([195.135.220.15]:53368 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726642AbfFQOir (ORCPT ); Mon, 17 Jun 2019 10:38:47 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 8AAABAEC3; Mon, 17 Jun 2019 14:38:44 +0000 (UTC) Date: Mon, 17 Jun 2019 16:38:42 +0200 From: Michal Hocko To: Waiman Long Cc: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Roman Gushchin , Johannes Weiner , Shakeel Butt , Vladimir Davydov , linux-api@vger.kernel.org Subject: Re: [PATCH] mm, memcg: Report number of memcg caches in slabinfo Message-ID: <20190617143842.GC1492@dhcp22.suse.cz> References: <20190617142149.5245-1-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190617142149.5245-1-longman@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [Cc linux-api] On Mon 17-06-19 10:21:49, Waiman Long wrote: > There are concerns about memory leaks from extensive use of memory > cgroups as each memory cgroup creates its own set of kmem caches. There > is a possiblity that the memcg kmem caches may remain even after the > memory cgroup removal. > > Therefore, it will be useful to show how many memcg caches are present > for each of the kmem caches. How is a user going to use that information? Btw. Don't we have an interface to display the number of (dead) cgroups? Keeping the rest of the email for the reference. > As slabinfo reporting code has to iterate > through all the memcg caches to get the final numbers anyway, there is > no additional cost in reporting the number of memcg caches available. > > The slabinfo version is bumped up to 2.2 as a new "" column > is added at the end. > > Signed-off-by: Waiman Long > --- > mm/slab_common.c | 24 ++++++++++++++++-------- > 1 file changed, 16 insertions(+), 8 deletions(-) > > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 58251ba63e4a..c7aa47a99b2b 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -1308,13 +1308,13 @@ static void print_slabinfo_header(struct seq_file *m) > * without _too_ many complaints. > */ > #ifdef CONFIG_DEBUG_SLAB > - seq_puts(m, "slabinfo - version: 2.1 (statistics)\n"); > + seq_puts(m, "slabinfo - version: 2.2 (statistics)\n"); > #else > - seq_puts(m, "slabinfo - version: 2.1\n"); > + seq_puts(m, "slabinfo - version: 2.2\n"); > #endif > seq_puts(m, "# name "); > seq_puts(m, " : tunables "); > - seq_puts(m, " : slabdata "); > + seq_puts(m, " : slabdata "); > #ifdef CONFIG_DEBUG_SLAB > seq_puts(m, " : globalstat "); > seq_puts(m, " : cpustat "); > @@ -1338,14 +1338,18 @@ void slab_stop(struct seq_file *m, void *p) > mutex_unlock(&slab_mutex); > } > > -static void > +/* > + * Return number of memcg caches. > + */ > +static unsigned int > memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info) > { > struct kmem_cache *c; > struct slabinfo sinfo; > + unsigned int cnt = 0; > > if (!is_root_cache(s)) > - return; > + return 0; > > for_each_memcg_cache(c, s) { > memset(&sinfo, 0, sizeof(sinfo)); > @@ -1356,17 +1360,20 @@ memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info) > info->shared_avail += sinfo.shared_avail; > info->active_objs += sinfo.active_objs; > info->num_objs += sinfo.num_objs; > + cnt++; > } > + return cnt; > } > > static void cache_show(struct kmem_cache *s, struct seq_file *m) > { > struct slabinfo sinfo; > + unsigned int nr_memcg_caches; > > memset(&sinfo, 0, sizeof(sinfo)); > get_slabinfo(s, &sinfo); > > - memcg_accumulate_slabinfo(s, &sinfo); > + nr_memcg_caches = memcg_accumulate_slabinfo(s, &sinfo); > > seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", > cache_name(s), sinfo.active_objs, sinfo.num_objs, s->size, > @@ -1374,8 +1381,9 @@ static void cache_show(struct kmem_cache *s, struct seq_file *m) > > seq_printf(m, " : tunables %4u %4u %4u", > sinfo.limit, sinfo.batchcount, sinfo.shared); > - seq_printf(m, " : slabdata %6lu %6lu %6lu", > - sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail); > + seq_printf(m, " : slabdata %6lu %6lu %6lu %3u", > + sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail, > + nr_memcg_caches); > slabinfo_show_stats(m, s); > seq_putc(m, '\n'); > } > -- > 2.18.1 -- Michal Hocko SUSE Labs