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,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 8C934C433DB for ; Fri, 29 Jan 2021 14:55:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DB88564E02 for ; Fri, 29 Jan 2021 14:55:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DB88564E02 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=virtuozzo.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 576216B0006; Fri, 29 Jan 2021 09:55:49 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 526B36B006C; Fri, 29 Jan 2021 09:55:49 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4643E6B0070; Fri, 29 Jan 2021 09:55:49 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0232.hostedemail.com [216.40.44.232]) by kanga.kvack.org (Postfix) with ESMTP id 2FD3C6B0006 for ; Fri, 29 Jan 2021 09:55:49 -0500 (EST) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id E3B1B8249980 for ; Fri, 29 Jan 2021 14:55:48 +0000 (UTC) X-FDA: 77759111976.17.bit65_560faa8275a9 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin17.hostedemail.com (Postfix) with ESMTP id C2AE4180D0184 for ; Fri, 29 Jan 2021 14:55:48 +0000 (UTC) X-HE-Tag: bit65_560faa8275a9 X-Filterd-Recvd-Size: 7181 Received: from relay.sw.ru (relay.sw.ru [185.231.240.75]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Fri, 29 Jan 2021 14:55:48 +0000 (UTC) Received: from [192.168.15.12] by relay.sw.ru with esmtp (Exim 4.94) (envelope-from ) id 1l5VB7-0017WU-Cn; Fri, 29 Jan 2021 17:55:17 +0300 Subject: Re: [v5 PATCH 08/11] mm: vmscan: use per memcg nr_deferred of shrinker To: Yang Shi , guro@fb.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> <20210127233345.339910-9-shy828301@gmail.com> From: Kirill Tkhai Message-ID: Date: Fri, 29 Jan 2021 17:55:19 +0300 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: <20210127233345.339910-9-shy828301@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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 28.01.2021 02:33, Yang Shi wrote: > Use per memcg's nr_deferred for memcg aware shrinkers. The shrinker's nr_deferred > will be used in the following cases: > 1. Non memcg aware shrinkers > 2. !CONFIG_MEMCG > 3. memcg is disabled by boot parameter > > Signed-off-by: Yang Shi > --- > mm/vmscan.c | 87 ++++++++++++++++++++++++++++++++++++++++++++--------- > 1 file changed, 73 insertions(+), 14 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 20be0db291fe..e1f8960f5cf6 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -205,7 +205,8 @@ static int expand_one_shrinker_info(struct mem_cgroup *memcg, > > for_each_node(nid) { > old = rcu_dereference_protected( > - mem_cgroup_nodeinfo(memcg, nid)->shrinker_info, true); > + mem_cgroup_nodeinfo(memcg, nid)->shrinker_info, > + lockdep_is_held(&shrinker_rwsem)); Won't it better to pack this repeating pattern into helper function, e.g.: static struct shrinker_info memcg_shrinker_info(struct mem_cgroup *memcg, int nid) { return rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info, lockdep_is_held(&shrinker_rwsem)); } ? Even shrink_slab_memcg() may want to use it. > /* Not yet online memcg */ > if (!old) > return 0; > @@ -239,7 +240,8 @@ void free_shrinker_info(struct mem_cgroup *memcg) > > for_each_node(nid) { > pn = mem_cgroup_nodeinfo(memcg, nid); > - info = rcu_dereference_protected(pn->shrinker_info, true); > + info = rcu_dereference_protected(pn->shrinker_info, > + lockdep_is_held(&shrinker_rwsem)); > if (info) > kvfree(info); > rcu_assign_pointer(pn->shrinker_info, NULL); > @@ -360,6 +362,27 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) > up_write(&shrinker_rwsem); > } > > +static long count_nr_deferred_memcg(int nid, struct shrinker *shrinker, > + struct mem_cgroup *memcg) > +{ > + struct shrinker_info *info; > + > + info = rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info, > + lockdep_is_held(&shrinker_rwsem)); > + return atomic_long_xchg(&info->nr_deferred[shrinker->id], 0); > +} > + > +static long set_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker, > + struct mem_cgroup *memcg) > +{ > + struct shrinker_info *info; > + > + info = rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info, > + lockdep_is_held(&shrinker_rwsem)); > + > + return atomic_long_add_return(nr, &info->nr_deferred[shrinker->id]); > +} > + > static bool cgroup_reclaim(struct scan_control *sc) > { > return sc->target_mem_cgroup; > @@ -398,6 +421,18 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) > { > } > > +static long count_nr_deferred_memcg(int nid, struct shrinker *shrinker, > + struct mem_cgroup *memcg) > +{ > + return 0; > +} > + > +static long set_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker, > + struct mem_cgroup *memcg) > +{ > + return 0; > +} > + > static bool cgroup_reclaim(struct scan_control *sc) > { > return false; > @@ -409,6 +444,39 @@ static bool writeback_throttling_sane(struct scan_control *sc) > } > #endif > > +static long count_nr_deferred(struct shrinker *shrinker, > + struct shrink_control *sc) > +{ > + int nid = sc->nid; > + > + if (!(shrinker->flags & SHRINKER_NUMA_AWARE)) > + nid = 0; > + > + if (sc->memcg && > + (shrinker->flags & SHRINKER_MEMCG_AWARE)) > + return count_nr_deferred_memcg(nid, shrinker, > + sc->memcg); > + > + return atomic_long_xchg(&shrinker->nr_deferred[nid], 0); > +} > + > + > +static long set_nr_deferred(long nr, struct shrinker *shrinker, > + struct shrink_control *sc) > +{ > + int nid = sc->nid; > + > + if (!(shrinker->flags & SHRINKER_NUMA_AWARE)) > + nid = 0; > + > + if (sc->memcg && > + (shrinker->flags & SHRINKER_MEMCG_AWARE)) > + return set_nr_deferred_memcg(nr, nid, shrinker, > + sc->memcg); > + > + return atomic_long_add_return(nr, &shrinker->nr_deferred[nid]); > +} > + > /* > * This misses isolated pages which are not accounted for to save counters. > * As the data only determines if reclaim or compaction continues, it is > @@ -545,14 +613,10 @@ static unsigned long do_shrink_slab(struct shrink_control *shrinkctl, > long freeable; > long nr; > long new_nr; > - int nid = shrinkctl->nid; > long batch_size = shrinker->batch ? shrinker->batch > : SHRINK_BATCH; > long scanned = 0, next_deferred; > > - if (!(shrinker->flags & SHRINKER_NUMA_AWARE)) > - nid = 0; > - > freeable = shrinker->count_objects(shrinker, shrinkctl); > if (freeable == 0 || freeable == SHRINK_EMPTY) > return freeable; > @@ -562,7 +626,7 @@ static unsigned long do_shrink_slab(struct shrink_control *shrinkctl, > * and zero it so that other concurrent shrinker invocations > * don't also do this scanning work. > */ > - nr = atomic_long_xchg(&shrinker->nr_deferred[nid], 0); > + nr = count_nr_deferred(shrinker, shrinkctl); > > total_scan = nr; > if (shrinker->seeks) { > @@ -653,14 +717,9 @@ static unsigned long do_shrink_slab(struct shrink_control *shrinkctl, > next_deferred = 0; > /* > * move the unused scan count back into the shrinker in a > - * manner that handles concurrent updates. If we exhausted the > - * scan, there is no need to do an update. > + * manner that handles concurrent updates. > */ > - if (next_deferred > 0) > - new_nr = atomic_long_add_return(next_deferred, > - &shrinker->nr_deferred[nid]); > - else > - new_nr = atomic_long_read(&shrinker->nr_deferred[nid]); > + new_nr = set_nr_deferred(next_deferred, shrinker, shrinkctl); > > trace_mm_shrink_slab_end(shrinker, shrinkctl->nid, freed, nr, new_nr, total_scan); > return freed; >