From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4E22B320F for ; Sun, 4 May 2025 05:19:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746335993; cv=none; b=q/PYZHiICc4SUHk/KvPXOZfvfdUWaN42yyuT/mA0f8HeeTXdSMkS4nRfpeLyRhLZoZzXTC+12BiQd5sGdyyOyRFnCFLjX9QbunuCvp7ugVdNSVAqoDkRgzTC9NWUBum9Qjtflv41im2xHVYrDplw/+dAK3RtE6mj5SvxmxpxCUU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746335993; c=relaxed/simple; bh=q/MhSz/0ZA8TsoU2KfkOcPE+jh27OA7zv8GWU/4o85Y=; h=Date:To:From:Subject:Message-Id; b=HNhW97/s4PkHZMyME/sQ74BnCfq9evrSuwyAdSl+bYnVtry3clkXCZ+XSO4X4+vWVyjpgNHINWHI9CsW4PbAJH2RIR+4pxdNHAEK5BzPzve7RwhSjkPdq2vYcZDkEomS4tuewWq5B7JEqQ5FM4bSVuJrtLzwjtSzDZ8G9q62c3M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=JOimtnW+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="JOimtnW+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2249EC4CEE9; Sun, 4 May 2025 05:19:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1746335993; bh=q/MhSz/0ZA8TsoU2KfkOcPE+jh27OA7zv8GWU/4o85Y=; h=Date:To:From:Subject:From; b=JOimtnW+AhPTBgwW9fZ9dJQTAIIB4ZFUF7xucrGRWbw/9cXoM6ljFZYC1puvwM0cl Seb9WG3dEMxwdHQOT8VbBNuPSQEhuKBRZaLWHYR3ifGDiawW9A5dePjZ6guruFZ3iK VXcz+BGc7JOZaUMRmwelas0sbZ3l75+9ZrqSOWEU= Date: Sat, 03 May 2025 22:19:52 -0700 To: mm-commits@vger.kernel.org,tj@kernel.org,shuah@kernel.org,shakeel.butt@linux.dev,roman.gushchin@linux.dev,muchun.song@linux.dev,mkoutny@suse.com,mhocko@kernel.org,hannes@cmpxchg.org,longman@redhat.com,akpm@linux-foundation.org From: Andrew Morton Subject: + selftests-memcg-increase-error-tolerance-of-child-memorycurrent-check-in-test_memcg_protection.patch added to mm-new branch Message-Id: <20250504051953.2249EC4CEE9@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: selftests: memcg: increase error tolerance of child memory.current check in test_memcg_protection() has been added to the -mm mm-new branch. Its filename is selftests-memcg-increase-error-tolerance-of-child-memorycurrent-check-in-test_memcg_protection.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-memcg-increase-error-tolerance-of-child-memorycurrent-check-in-test_memcg_protection.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Waiman Long Subject: selftests: memcg: increase error tolerance of child memory.current check in test_memcg_protection() Date: Thu, 1 May 2025 21:04:43 -0400 The test_memcg_protection() function is used for the test_memcg_min and test_memcg_low sub-tests. This function generates a set of parent/child cgroups like: parent: memory.min/low = 50M child 0: memory.min/low = 75M, memory.current = 50M child 1: memory.min/low = 25M, memory.current = 50M child 2: memory.min/low = 0, memory.current = 50M After applying memory pressure, the function expects the following actual memory usages. parent: memory.current ~= 50M child 0: memory.current ~= 29M child 1: memory.current ~= 21M child 2: memory.current ~= 0 In reality, the actual memory usages can differ quite a bit from the expected values. It uses an error tolerance of 10% with the values_close() helper. Both the test_memcg_min and test_memcg_low sub-tests can fail sporadically because the actual memory usage exceeds the 10% error tolerance. Below are a sample of the usage data of the tests runs that fail. Child Actual usage Expected usage %err ----- ------------ -------------- ---- 1 16990208 22020096 -12.9% 1 17252352 22020096 -12.1% 0 37699584 30408704 +10.7% 1 14368768 22020096 -21.0% 1 16871424 22020096 -13.2% The current 10% error tolerenace might be right at the time test_memcontrol.c was first introduced in v4.18 kernel, but memory reclaim have certainly evolved quite a bit since then which may result in a bit more run-to-run variation than previously expected. Increase the error tolerance to 15% for child 0 and 20% for child 1 to minimize the chance of this type of failure. The tolerance is bigger for child 1 because an upswing in child 0 corresponds to a smaller %err than a similar downswing in child 1 due to the way %err is used in values_close(). Before this patch, a 100 test runs of test_memcontrol produced the following results: 17 not ok 1 test_memcg_min 22 not ok 2 test_memcg_low After applying this patch, there were no test failure for test_memcg_min and test_memcg_low in 100 test runs. However, these tests may still fail once in a while if the memory usage goes beyond the newly extended range. Link: https://lkml.kernel.org/r/20250502010443.106022-3-longman@redhat.com Signed-off-by: Waiman Long Cc: Johannes Weiner Cc: Michal Hocko Cc: Michal Koutný Cc: Muchun Song Cc: Roman Gushchin Cc: Shakeel Butt Cc: Shuah Khan Cc: Tejun Heo Signed-off-by: Andrew Morton --- tools/testing/selftests/cgroup/test_memcontrol.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/tools/testing/selftests/cgroup/test_memcontrol.c~selftests-memcg-increase-error-tolerance-of-child-memorycurrent-check-in-test_memcg_protection +++ a/tools/testing/selftests/cgroup/test_memcontrol.c @@ -496,10 +496,10 @@ static int test_memcg_protection(const c for (i = 0; i < ARRAY_SIZE(children); i++) c[i] = cg_read_long(children[i], "memory.current"); - if (!values_close(c[0], MB(29), 10)) + if (!values_close(c[0], MB(29), 15)) goto cleanup; - if (!values_close(c[1], MB(21), 10)) + if (!values_close(c[1], MB(21), 20)) goto cleanup; if (c[3] != 0) _ Patches currently in -mm which might be from longman@redhat.com are selftests-memcg-allow-low-event-with-no-memorylow-and-memory_recursiveprot-on.patch selftests-memcg-increase-error-tolerance-of-child-memorycurrent-check-in-test_memcg_protection.patch