From nobody Sun Feb 8 09:27:21 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 7959AC001E0 for ; Tue, 1 Aug 2023 13:56:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234430AbjHAN4o (ORCPT ); Tue, 1 Aug 2023 09:56:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53978 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234230AbjHAN4i (ORCPT ); Tue, 1 Aug 2023 09:56:38 -0400 Received: from mail-qt1-x829.google.com (mail-qt1-x829.google.com [IPv6:2607:f8b0:4864:20::829]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D06A2134 for ; Tue, 1 Aug 2023 06:56:34 -0700 (PDT) Received: by mail-qt1-x829.google.com with SMTP id d75a77b69052e-406b9bcad5dso28475751cf.2 for ; Tue, 01 Aug 2023 06:56:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20221208.gappssmtp.com; s=20221208; t=1690898193; x=1691502993; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=XJLGW04mxEToFfRDeoOpyp00hE8LNX9fFBjKrCRhwps=; b=iLH7vqnb28PIkYe34u+mDj70sMwzhlg2Nc9Lt2f4INh+KceFZ4zMmArs8alLU4u0W1 xuDos8oBmOj2eI8hOcKxNyjB9tlUl5gULORkj9AFCEfX0mZRPKbeVkBWvQtw3rU0aFZL qGVxwxzioM5kQNEUjBSr/VS4Yudj1ZSYn+Pk67O/2OGEHBnObl0Oxjqh5w56/qFguZeF 0P4o7c44YclUPTxHlqXaMpNGRbK83ZiiVTuS+udod4EI3YUzNvZi7AAMVqNq6u/dr4Mv NoUhcNOKuM2pesfsikO7xYyIiTwESwnALMqSuZQOqB6X+3xxzvPkTuuBoUokQu/Pu+Gu /KBQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690898193; x=1691502993; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=XJLGW04mxEToFfRDeoOpyp00hE8LNX9fFBjKrCRhwps=; b=AGMfqMG5jNtHIavMYjW1EwxCE2SXDgOqSmpSD71VJk0HK430wNWLmnI+jbzztCdYz1 aO/PT6oxV6hpcKl46KveXIYYEL/HQMRdbNhfdVyOr1aVF6jGu1J663Z/Ea0wZ8jLbnrb /EGapzIhzG5Iv/jAH7602UoaQSkLsGPmac66KHUJZ0AtMGMg2x5I5/v3YuJqJhnx8gQF e2y1dN137Uj4Eam5QxNXyV91K6WIpssmo7U5E86N910sitln1OCg7QeYq0aAAlns42nT ag6AO+/N4Km24KuVHbX9/c0Bjc4BMtrYSjIfjRpsTFwQbJDk+neUSwzFdNE4seHE57lk 4PJw== X-Gm-Message-State: ABy/qLb6jQEw3xOIYK7dqDydpuQzowlfztDDILeAU2xbFq8NkuziNP1R yXMdfcUYv1dXUQUIlhW8NZCScLwBpDxEyygY6weQdA== X-Google-Smtp-Source: APBJJlHENlK+WateqGlF3CA9rHgN32+u2UbuYvusGApJRTWPvSgkpYMrWjdUy8Nk/EukrVLPAteZTQ== X-Received: by 2002:a05:622a:1a18:b0:402:4bf3:7f41 with SMTP id f24-20020a05622a1a1800b004024bf37f41mr12515923qtb.29.1690898193176; Tue, 01 Aug 2023 06:56:33 -0700 (PDT) Received: from localhost (2603-7000-0c01-2716-8f57-5681-ccd3-4a2e.res6.spectrum.com. [2603:7000:c01:2716:8f57:5681:ccd3:4a2e]) by smtp.gmail.com with ESMTPSA id c27-20020ac8009b000000b004054b435f8csm4446390qtg.65.2023.08.01.06.56.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Aug 2023 06:56:32 -0700 (PDT) From: Johannes Weiner To: Andrew Morton Cc: Roman Gushchin , Michal Hocko , "Paul E. McKenney" , linux-kselftest@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] selftests: cgroup: fix test_kmem_basic false positives Date: Tue, 1 Aug 2023 09:56:32 -0400 Message-ID: <20230801135632.1768830-1-hannes@cmpxchg.org> X-Mailer: git-send-email 2.41.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This test fails routinely in our prod testing environment, and I can reproduce it locally as well. The test allocates dcache inside a cgroup, then drops the memory limit and checks that usage drops correspondingly. The reason it fails is because dentries are freed with an RCU delay - a debugging sleep shows that usage drops as expected shortly after. Insert a 1s sleep after dropping the limit. This should be good enough, assuming that machines running those tests are otherwise not very busy. Signed-off-by: Johannes Weiner Acked-by: Paul E. McKenney --- tools/testing/selftests/cgroup/test_kmem.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/tools/testing/selftests/cgroup/test_kmem.c b/tools/testing/sel= ftests/cgroup/test_kmem.c index 258ddc565deb..1b2cec9d18a4 100644 --- a/tools/testing/selftests/cgroup/test_kmem.c +++ b/tools/testing/selftests/cgroup/test_kmem.c @@ -70,6 +70,10 @@ static int test_kmem_basic(const char *root) goto cleanup; =20 cg_write(cg, "memory.high", "1M"); + + /* wait for RCU freeing */ + sleep(1); + slab1 =3D cg_read_key_long(cg, "memory.stat", "slab "); if (slab1 <=3D 0) goto cleanup; --=20 2.41.0