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 30D67C433E0 for ; Fri, 29 Jan 2021 14:59:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 84C1564E03 for ; Fri, 29 Jan 2021 14:59:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 84C1564E03 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 B5EB16B0006; Fri, 29 Jan 2021 09:59:39 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B0FF26B0070; Fri, 29 Jan 2021 09:59:39 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A25E46B0071; Fri, 29 Jan 2021 09:59:39 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0096.hostedemail.com [216.40.44.96]) by kanga.kvack.org (Postfix) with ESMTP id 8B69B6B0006 for ; Fri, 29 Jan 2021 09:59:39 -0500 (EST) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 8CB6E3628 for ; Fri, 29 Jan 2021 14:59:37 +0000 (UTC) X-FDA: 77759121594.09.baby53_260c6be275a9 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin09.hostedemail.com (Postfix) with ESMTP id 4AE8F180AD822 for ; Fri, 29 Jan 2021 14:59:37 +0000 (UTC) X-HE-Tag: baby53_260c6be275a9 X-Filterd-Recvd-Size: 7635 Received: from relay.sw.ru (relay.sw.ru [185.231.240.75]) by imf11.hostedemail.com (Postfix) with ESMTP for ; Fri, 29 Jan 2021 14:59:36 +0000 (UTC) Received: from [192.168.15.12] by relay.sw.ru with esmtp (Exim 4.94) (envelope-from ) id 1l5VEo-0017Xj-VM; Fri, 29 Jan 2021 17:59:07 +0300 Subject: Re: [v5 PATCH 08/11] mm: vmscan: use per memcg nr_deferred of shrinker From: Kirill Tkhai 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> Message-ID: <7c0152a2-f846-c696-4dec-63f285d20ae5@virtuozzo.com> Date: Fri, 29 Jan 2021 17:59:09 +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: 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 29.01.2021 17:55, Kirill Tkhai wrote: > 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. Hm, I see you already introduced a helper in [10/11], but it is used in only place. Then, we should use it for all places (introduce the helper earlier). >> /* 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; >> >