From nobody Tue Feb 10 05:10:48 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1C016C6FD1D for ; Thu, 30 Mar 2023 19:18:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230081AbjC3TSe (ORCPT ); Thu, 30 Mar 2023 15:18:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48658 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232064AbjC3TSV (ORCPT ); Thu, 30 Mar 2023 15:18:21 -0400 Received: from mail-pj1-x1049.google.com (mail-pj1-x1049.google.com [IPv6:2607:f8b0:4864:20::1049]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8A554FF27 for ; Thu, 30 Mar 2023 12:18:15 -0700 (PDT) Received: by mail-pj1-x1049.google.com with SMTP id gj9-20020a17090b108900b0024038c818a0so6245240pjb.7 for ; Thu, 30 Mar 2023 12:18:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1680203895; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=zjUVlGzaNGh8M5BDppplh7Z2E1z5drNgoNePIuD8ZZo=; b=EVT1tk0hlY3K/RTYvcQHMKPpwQPVXOnpdSgQM68BKQtZmfmON2APgqvMOvMMFyRoss Dmd2H4VUZwWGIfs6kzYLS/yY0LBdZ4oH1VkvSRWDGcSOJqUREz+4yAA6vO0jGdRbUllx xh0AWez/MaDxogJM7rwIORKSy2FNGdepATzkqraYhiO3RCB8HnWcqe3zSlq35IxkzxtC FV1PJ6neoxu760xZAlTGk8nkupYvKz5UcVjEtp57Ggrbl9Lds+WScYdzag5BG/1gW5Yv DUw8gcccaLuVJ49JXssrnmfFrYddyvv++tF0t2hffuUaTqszDGsJ7ZLQoChqmjJGkrqP YfTQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680203895; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=zjUVlGzaNGh8M5BDppplh7Z2E1z5drNgoNePIuD8ZZo=; b=wFKZaBWFVlwqnl1xgLnVYnQFYNV61omOeeL/TJs6n0bz0XiVh3BIn4wKUsgMoEzTix 5/dDCf9PP7rSw8aQjkO475/iXDa1FBnNNwHdTjARoF6d4AVnw2c5fdl4oLtI8Bxtbbm0 i4rqiQggSz/5aZftLaAe07+2iEUj47gLmAywSFoF3CvEUGRIoR3k0tK4b/+kS1/PrnR3 GmNIiW6ZYtHyE+jN1F6tXqe5mYx+FUXC1XVkSfZnDxKWx6Q8BpdHZcZxZROO3m+HPzU8 p2HAnx1QhRJk4rlN68eK1GLnkCsfvNaYNcZ0qRuYypK+w4mVPl41xvzwfl7Sk6F6XlNN IPoA== X-Gm-Message-State: AAQBX9cPbz6Guvz7+jsW28PrGQDpNAE1yK2PcLUG6niOBMygq+JBDHX2 X2Z+L+sA/Z4Ebn1QH1rn9pmeU5HyVXZ/i2p0 X-Google-Smtp-Source: AKy350YjU2Y2MgqNkqgZoIOPOW0+HOYv1MqQ0pV2FUPZVEGY798zCaQjIBhDtJyF0YZxiEsyw9QKlZMU8q/qm34J X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2327]) (user=yosryahmed job=sendgmr) by 2002:a17:902:6b44:b0:1a2:6e4d:7832 with SMTP id g4-20020a1709026b4400b001a26e4d7832mr2680127plt.1.1680203894775; Thu, 30 Mar 2023 12:18:14 -0700 (PDT) Date: Thu, 30 Mar 2023 19:17:59 +0000 In-Reply-To: <20230330191801.1967435-1-yosryahmed@google.com> Mime-Version: 1.0 References: <20230330191801.1967435-1-yosryahmed@google.com> X-Mailer: git-send-email 2.40.0.348.gf938b09366-goog Message-ID: <20230330191801.1967435-7-yosryahmed@google.com> Subject: [PATCH v3 6/8] workingset: memcg: sleep when flushing stats in workingset_refault() From: Yosry Ahmed To: Tejun Heo , Josef Bacik , Jens Axboe , Zefan Li , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton , "=?UTF-8?q?Michal=20Koutn=C3=BD?=" Cc: Vasily Averin , cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org, Yosry Ahmed , Michal Hocko Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" In workingset_refault(), we call mem_cgroup_flush_stats_atomic_ratelimited() to read accurate stats within an RCU read section and with sleeping disallowed. Move the call above the RCU read section to make it non-atomic. Flushing is an expensive operation that scales with the number of cpus and the number of cgroups in the system, so avoid doing it atomically where possible. Since workingset_refault() is the only caller of mem_cgroup_flush_stats_atomic_ratelimited(), just make it non-atomic, and rename it to mem_cgroup_flush_stats_ratelimited(). Signed-off-by: Yosry Ahmed Acked-by: Shakeel Butt Acked-by: Johannes Weiner Acked-by: Michal Hocko --- include/linux/memcontrol.h | 4 ++-- mm/memcontrol.c | 4 ++-- mm/workingset.c | 5 +++-- 3 files changed, 7 insertions(+), 6 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index b424ba3ebd09..a4bc3910a2eb 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1038,7 +1038,7 @@ static inline unsigned long lruvec_page_state_local(s= truct lruvec *lruvec, =20 void mem_cgroup_flush_stats(void); void mem_cgroup_flush_stats_atomic(void); -void mem_cgroup_flush_stats_atomic_ratelimited(void); +void mem_cgroup_flush_stats_ratelimited(void); =20 void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item i= dx, int val); @@ -1540,7 +1540,7 @@ static inline void mem_cgroup_flush_stats_atomic(void) { } =20 -static inline void mem_cgroup_flush_stats_atomic_ratelimited(void) +static inline void mem_cgroup_flush_stats_ratelimited(void) { } =20 diff --git a/mm/memcontrol.c b/mm/memcontrol.c index a2ce3aa10d94..361c0bbf7283 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -673,10 +673,10 @@ void mem_cgroup_flush_stats_atomic(void) do_flush_stats(true); } =20 -void mem_cgroup_flush_stats_atomic_ratelimited(void) +void mem_cgroup_flush_stats_ratelimited(void) { if (time_after64(jiffies_64, READ_ONCE(flush_next_time))) - mem_cgroup_flush_stats_atomic(); + mem_cgroup_flush_stats(); } =20 static void flush_memcg_stats_dwork(struct work_struct *w) diff --git a/mm/workingset.c b/mm/workingset.c index dab0c362b9e3..3025beee9b34 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -406,6 +406,9 @@ void workingset_refault(struct folio *folio, void *shad= ow) unpack_shadow(shadow, &memcgid, &pgdat, &eviction, &workingset); eviction <<=3D bucket_order; =20 + /* Flush stats (and potentially sleep) before holding RCU read lock */ + mem_cgroup_flush_stats_ratelimited(); + rcu_read_lock(); /* * Look up the memcg associated with the stored ID. It might @@ -461,8 +464,6 @@ void workingset_refault(struct folio *folio, void *shad= ow) lruvec =3D mem_cgroup_lruvec(memcg, pgdat); =20 mod_lruvec_state(lruvec, WORKINGSET_REFAULT_BASE + file, nr); - - mem_cgroup_flush_stats_atomic_ratelimited(); /* * Compare the distance to the existing workingset size. We * don't activate pages that couldn't stay resident even if --=20 2.40.0.348.gf938b09366-goog