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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 084E4C433E0 for ; Fri, 29 Jan 2021 15:52:44 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4CF1164D9A for ; Fri, 29 Jan 2021 15:52:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4CF1164D9A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 814A36B006C; Fri, 29 Jan 2021 10:52:42 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 79DA78D0002; Fri, 29 Jan 2021 10:52:42 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6676F8D0001; Fri, 29 Jan 2021 10:52:42 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0154.hostedemail.com [216.40.44.154]) by kanga.kvack.org (Postfix) with ESMTP id 4C03A6B006C for ; Fri, 29 Jan 2021 10:52:42 -0500 (EST) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 0ADBD180AD83A for ; Fri, 29 Jan 2021 15:52:42 +0000 (UTC) X-FDA: 77759255364.16.pie07_5b1166d275a9 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin16.hostedemail.com (Postfix) with ESMTP id DF974100E6903 for ; Fri, 29 Jan 2021 15:52:41 +0000 (UTC) X-HE-Tag: pie07_5b1166d275a9 X-Filterd-Recvd-Size: 4369 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf33.hostedemail.com (Postfix) with ESMTP for ; Fri, 29 Jan 2021 15:52:41 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id EF852AC48; Fri, 29 Jan 2021 15:52:39 +0000 (UTC) To: Yang Shi , guro@fb.com, ktkhai@virtuozzo.com, shakeelb@google.com, david@fromorbit.com, hannes@cmpxchg.org, mhocko@suse.com, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org References: <20210127233345.339910-1-shy828301@gmail.com> <20210127233345.339910-11-shy828301@gmail.com> From: Vlastimil Babka Subject: Re: [v5 PATCH 10/11] mm: memcontrol: reparent nr_deferred when memcg offline Message-ID: <0eee1cbd-4149-9f03-615d-18c81b8a85af@suse.cz> Date: Fri, 29 Jan 2021 16:52:39 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: <20210127233345.339910-11-shy828301@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable 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 1/28/21 12:33 AM, Yang Shi wrote: > Now shrinker's nr_deferred is per memcg for memcg aware shrinkers, add = to parent's > corresponding nr_deferred when memcg offline. >=20 > Signed-off-by: Yang Shi Acked-by: Vlastimil Babka A question somewhat outside of the scope of the series. Should we shrink = before reparenting on memcg offline? Would it make more sense than assume the km= emcg objects that are still cached are used also by others? > --- > include/linux/memcontrol.h | 1 + > mm/memcontrol.c | 1 + > mm/vmscan.c | 31 +++++++++++++++++++++++++++++++ > 3 files changed, 33 insertions(+) >=20 > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index e0384367e07d..fe1375f08881 100644 > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -1586,6 +1586,7 @@ extern int alloc_shrinker_info(struct mem_cgroup = *memcg); > extern void free_shrinker_info(struct mem_cgroup *memcg); > extern void set_shrinker_bit(struct mem_cgroup *memcg, > int nid, int shrinker_id); > +extern void reparent_shrinker_deferred(struct mem_cgroup *memcg); > #else > #define mem_cgroup_sockets_enabled 0 > static inline void mem_cgroup_sk_alloc(struct sock *sk) { }; > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index f64ad0d044d9..21f36b73f36a 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -5282,6 +5282,7 @@ static void mem_cgroup_css_offline(struct cgroup_= subsys_state *css) > page_counter_set_low(&memcg->memory, 0); > =20 > memcg_offline_kmem(memcg); > + reparent_shrinker_deferred(memcg); > wb_memcg_offline(memcg); > =20 > drain_all_stock(memcg); > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 0373d7619d7b..55ad91a26ba3 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -386,6 +386,37 @@ static long set_nr_deferred_memcg(long nr, int nid= , struct shrinker *shrinker, > return atomic_long_add_return(nr, &info->nr_deferred[shrinker->id]); > } > =20 > +static struct shrinker_info *shrinker_info_protected(struct mem_cgroup= *memcg, > + int nid) > +{ > + return rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info, > + lockdep_is_held(&shrinker_rwsem)); > +} > + > +void reparent_shrinker_deferred(struct mem_cgroup *memcg) > +{ > + int i, nid; > + long nr; > + struct mem_cgroup *parent; > + struct shrinker_info *child_info, *parent_info; > + > + parent =3D parent_mem_cgroup(memcg); > + if (!parent) > + parent =3D root_mem_cgroup; > + > + /* Prevent from concurrent shrinker_info expand */ > + down_read(&shrinker_rwsem); > + for_each_node(nid) { > + child_info =3D shrinker_info_protected(memcg, nid); > + parent_info =3D shrinker_info_protected(parent, nid); > + for (i =3D 0; i < shrinker_nr_max; i++) { > + nr =3D atomic_long_read(&child_info->nr_deferred[i]); > + atomic_long_add(nr, &parent_info->nr_deferred[i]); > + } > + } > + up_read(&shrinker_rwsem); > +} > + > static bool cgroup_reclaim(struct scan_control *sc) > { > return sc->target_mem_cgroup; >=20