From patchwork Thu Mar 30 19:18:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Yosry Ahmed X-Patchwork-Id: 13194767 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 9437EC77B6E for ; Thu, 30 Mar 2023 19:19:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230392AbjC3TTH (ORCPT ); Thu, 30 Mar 2023 15:19:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48674 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232213AbjC3TSj (ORCPT ); Thu, 30 Mar 2023 15:18:39 -0400 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0FD4510A97 for ; Thu, 30 Mar 2023 12:18:18 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-54574d6204aso197368167b3.15 for ; Thu, 30 Mar 2023 12:18:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1680203898; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=WbNC07VGnJucfMQdaVru/HWxeCTMcNM6hFkgQ/MCeFU=; b=PUv9MA0n+Z8fm7ErrGvHySjECm+JmVMmb7yIewlfjR/61XxilLPkk2HWdbFMTfUOaL VEd5S3Db2lj6fZaM1EVkiIBt/SsoMNdbAydQDGkFf9C+290T1e1uwhZ4tZ9DFf8Phq0h P4OVDvENTCX+3IndK3Cvs6OkRD4foG1c4Yew7PAGOLNrfjOHkmrszhM9+d8Istzt+wK/ krUK3yorRZOqS1BM/g9ye1FRB5jRNaXtQwUxDYcXcRNeFj0C93RhkVtRFak+8MvkC/U9 MW/LMGQgSZbJ8G2s7XbIxfyCgArJtDyQ9vNCBWNE1utNTCLeMAHTcanEcYFbU2EbD5hm feog== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680203898; 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=WbNC07VGnJucfMQdaVru/HWxeCTMcNM6hFkgQ/MCeFU=; b=r2FZY38tQchfcZbu1Zto7vGCPjKLZ79bXYzPv6r6JLMpMa83CHWU+K1rIUG+UMhG8R okB8/vRCOhGNfra4HTpKNBhzBjA5FdZWtmuX1ZGkYrRaqaLTIdxGCqvFC3uw5YN8VvcG gSla5WJD2o0/tLFMW4CTR2ziRUNGST92V1rWenmBagvAJzn3Gw5TOHrWJuwNM3/8Xs75 osIi0WrD11mAabsrDaTnGNPJzrU9+fAnQM/u8vAVAnlTJITe3BXntvW4QcTz29oVmLGo NqF3PClvpL1ot8NAdGEzCvhLzHDaxebtqZDIF2/EHwb8xeBVDZsXJMfBvkgT9Rggv/k/ eCEw== X-Gm-Message-State: AAQBX9e5hbLSzgBsr5fgJ2zaXqYWqnJ0ZYA7tUuaz8HXXho0YKYm0IAj FFgiAAwCf/bJ7bfAxum8PvIuRpu0R8xAArH1 X-Google-Smtp-Source: AKy350Z/bGsj2O9Q2OanxyiTVpU0KIn4cOhMHnfEJjh1llR4Xo1YrB6Sk31TDPAteoghtoX9TuixuaLotnLFVi3d X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2327]) (user=yosryahmed job=sendgmr) by 2002:a25:12d4:0:b0:b6e:d788:eba4 with SMTP id 203-20020a2512d4000000b00b6ed788eba4mr12664999ybs.6.1680203898630; Thu, 30 Mar 2023 12:18:18 -0700 (PDT) Date: Thu, 30 Mar 2023 19:18:01 +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: <20230330191801.1967435-9-yosryahmed@google.com> Subject: [PATCH v3 8/8] memcg: do not modify rstat tree for zero updates 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_Koutn=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-block@vger.kernel.org In some situations, we may end up calling memcg_rstat_updated() with a value of 0, which means the stat was not actually updated. An example is if we fail to reclaim any pages in shrink_folio_list(). Do not add the cgroup to the rstat updated tree in this case, to avoid unnecessarily flushing it. Signed-off-by: Yosry Ahmed Acked-by: Shakeel Butt Acked-by: Johannes Weiner Acked-by: Michal Hocko Reviewed-by: Michal Koutný --- mm/memcontrol.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 361c0bbf7283..a63ee2efa780 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -618,6 +618,9 @@ static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val) { unsigned int x; + if (!val) + return; + cgroup_rstat_updated(memcg->css.cgroup, smp_processor_id()); x = __this_cpu_add_return(stats_updates, abs(val));