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 E7C31239E7E for ; Tue, 19 Aug 2025 22:54:52 +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=1755644095; cv=none; b=P7CbGO475UkA128v/6NQ9Kjs3hHgvp3nM3aYHAM9BgxWgTfliO+jYxr1si9XI29/8n9wGiy55bq+GkCrYixtpsQbzwDqDgaoEke/SIo8zffU23EqiD9UXZLAl5zC4oJFZF8IfAdqhN8NWKkSWyVb0pKIrDB3kfLab+iy4VkhXnY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755644095; c=relaxed/simple; bh=jzO0FtU+A3tYdK1+KZUdurgde06uNdds7r8ePpTMvqw=; h=Date:To:From:Subject:Message-Id; b=C83DNUblv0IvFxhZw4ZNM9SK1nHjMI0fZu3Sr2qSLVaqQ9PeIyKVgRAaZ2XmvBqQ7zODVthFgNM+8XR8EgOv+3AWKLEYOgWt3HruoG10UY2JS/QzCII0dmYaCz3P4hJQ4+oKmGx74AdPZNiElPCB20ePfT8m5bAoCoaCR2dsowc= 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=Ouw8HFWC; 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="Ouw8HFWC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6539EC4CEF1; Tue, 19 Aug 2025 22:54:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1755644092; bh=jzO0FtU+A3tYdK1+KZUdurgde06uNdds7r8ePpTMvqw=; h=Date:To:From:Subject:From; b=Ouw8HFWC1semLy3up1xMkX0nKtRD5h2RUM5Leh+pOHXIIwVavhom1wAFaT3PDhmNa FPyZYnHhJBwzL8iSe4F/q7Toivn+ydqx9eUYZSOkJsGkoY5weSoLmRWsuXH0ONVQl9 0WO0iEO37xQEiBjMgAdl/yav/P+53YFw2IknrZYM= Date: Tue, 19 Aug 2025 15:54:51 -0700 To: mm-commits@vger.kernel.org,yaoma@linux.alibaba.com,tglx@linutronix.de,max.kellermann@ionos.com,lihuafei1@huawei.com,yaozhenguo1@gmail.com,akpm@linux-foundation.org From: Andrew Morton Subject: + watchdog-softlockup-fix-incorrect-cpu-utilization-output-during-softlockup-v2.patch added to mm-nonmm-unstable branch Message-Id: <20250819225452.6539EC4CEF1@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: watchdog/softlockup:Fix incorrect CPU utilization output during softlockup has been added to the -mm mm-nonmm-unstable branch. Its filename is watchdog-softlockup-fix-incorrect-cpu-utilization-output-during-softlockup-v2.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/watchdog-softlockup-fix-incorrect-cpu-utilization-output-during-softlockup-v2.patch This patch will later appear in the mm-nonmm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm 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: ZhenguoYao Subject: watchdog/softlockup:Fix incorrect CPU utilization output during softlockup Date: Mon, 18 Aug 2025 16:14:38 +0800 make get_16bit_precision() more accurate, fix comment layout Link: https://lkml.kernel.org/r/20250818081438.40540-1-yaozhenguo@jd.com Signed-off-by: ZhenguoYao Cc: Bitao Hu Cc: Li Huafei Cc: Max Kellermann Cc: Thomas Gleinxer Signed-off-by: Andrew Morton --- kernel/watchdog.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/kernel/watchdog.c~watchdog-softlockup-fix-incorrect-cpu-utilization-output-during-softlockup-v2 +++ a/kernel/watchdog.c @@ -425,7 +425,11 @@ static DEFINE_PER_CPU(u8, cpustat_tail); */ static u16 get_16bit_precision(u64 data_ns) { - return data_ns >> 24LL; /* 2^24ns ~= 16.8ms */ + /* + * 2^24ns ~= 16.8ms + * Round to the nearest multiple of 16.8 milliseconds. + */ + return (data_ns + (1 << 23)) >> 24LL; } static void update_cpustat(void) @@ -444,7 +448,8 @@ static void update_cpustat(void) old_stat = __this_cpu_read(cpustat_old[i]); new_stat = get_16bit_precision(cpustat[tracked_stats[i]]); util = DIV_ROUND_UP(100 * (new_stat - old_stat), sample_period_16); - /* Since we use 16-bit precision, the raw data will undergo + /* + * Since we use 16-bit precision, the raw data will undergo * integer division, which may sometimes result in data loss, * and then result might exceed 100%. To avoid confusion, * we enforce a 100% display cap when calculations exceed this threshold. _ Patches currently in -mm which might be from yaozhenguo1@gmail.com are watchdog-softlockup-fix-wrong-output-when-watchdog_thresh-3.patch watchdog-softlockup-fix-incorrect-cpu-utilization-output-during-softlockup.patch watchdog-softlockup-fix-incorrect-cpu-utilization-output-during-softlockup-v2.patch