From nobody Sun Feb 8 11:37:16 2026 Received: from SHSQR01.spreadtrum.com (unknown [222.66.158.135]) (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 D2AE420DF4 for ; Mon, 19 Feb 2024 07:47:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=222.66.158.135 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708328866; cv=none; b=h0nRIHJWV5lck8olfzplnQCSH0iEvkv2b8KfzVjSbyatB2Nhk379aI4E7nytJat0bW1RMJEGFfQjyEHNjj0USzFDhyqQS9VHH3nYiUerxe9lLG2tbsriTrCVFIak0fGwVNDBpajNTI/8HsJrd8S4gkLgNNYAo/FZGIEqKrF2HbQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708328866; c=relaxed/simple; bh=ewsDsPkbeobOE48ZRHp1eMRBk4DRcJdny5eRpEC1R6E=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=V/LS9qSsHGj2joBhy3CximfAYwYUWu2sC7bvv58GsRrbkc5l/AUBpwvRVOIb8pkXre4ejv8D3UIFZlmgs34e3lbTtFg10lOGaKrfmKH1XlgCH0jzw1U+oZZs325gL9hBGHrqWHjo+qasn+26uVH9ow4vI+Lp2QEwUm6RRMJBWjU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=unisoc.com; spf=pass smtp.mailfrom=unisoc.com; arc=none smtp.client-ip=222.66.158.135 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=unisoc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=unisoc.com Received: from dlp.unisoc.com ([10.29.3.86]) by SHSQR01.spreadtrum.com with ESMTP id 41J7kfiO037258; Mon, 19 Feb 2024 15:46:41 +0800 (+08) (envelope-from Xuewen.Yan@unisoc.com) Received: from SHDLP.spreadtrum.com (bjmbx01.spreadtrum.com [10.0.64.7]) by dlp.unisoc.com (SkyGuard) with ESMTPS id 4TdZNL0c0lz2KCvlD; Mon, 19 Feb 2024 15:46:10 +0800 (CST) Received: from BJ10918NBW01.spreadtrum.com (10.0.73.73) by BJMBX01.spreadtrum.com (10.0.64.7) with Microsoft SMTP Server (TLS) id 15.0.1497.23; Mon, 19 Feb 2024 15:46:39 +0800 From: Xuewen Yan To: , , CC: , , , , , , , Subject: [PATCH] workqueue: Control the frequency of intensive warning through cmdline Date: Mon, 19 Feb 2024 15:46:34 +0800 Message-ID: <20240219074634.2039-1-xuewen.yan@unisoc.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: SHCAS03.spreadtrum.com (10.0.1.207) To BJMBX01.spreadtrum.com (10.0.64.7) X-MAIL: SHSQR01.spreadtrum.com 41J7kfiO037258 Content-Type: text/plain; charset="utf-8" When CONFIG_WQ_CPU_INTENSIVE_REPORT is set, the kernel will report the work functions which violate the intensive_threshold_us repeatedly. And now, only when the violate times exceed 4 and is a power of 2, the kernel warning could be triggered. However, sometimes we want to print the warning every time when the work executed too long. Because sometimes, even if a long work execution time occurs only once, it may cause other work to be delayed for a long time. In order to freely control the frequency of printing, a boot argument is added so that the user can control the warning to be printed only after a certain number of work timeouts. Default, it would print warning every 4 times. Signed-off-by: Xuewen Yan --- Documentation/admin-guide/kernel-parameters.txt | 9 +++++++++ kernel/workqueue.c | 10 ++++++++-- 2 files changed, 17 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentatio= n/admin-guide/kernel-parameters.txt index 31b3a25680d0..599fc59fcf70 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -7225,6 +7225,15 @@ threshold repeatedly. They are likely good candidates for using WQ_UNBOUND workqueues instead. =20 + workqueue.cpu_intensive_warning_per_count=3D + If CONFIG_WQ_CPU_INTENSIVE_REPORT is set, the kernel + will report the work functions which violate the + intensive_threshold_us repeatedly. In order to prevent + the kernel log from being printed too frequently. + Control the frequency. + + Default, it will print one warning per 4 times. + workqueue.power_efficient Per-cpu workqueues are generally preferred because they show better performance thanks to cache diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 7b482a26d741..8e8cccf5329a 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -359,6 +359,10 @@ static const char *wq_affn_names[WQ_AFFN_NR_TYPES] =3D= { */ static unsigned long wq_cpu_intensive_thresh_us =3D ULONG_MAX; module_param_named(cpu_intensive_thresh_us, wq_cpu_intensive_thresh_us, ul= ong, 0644); +#ifdef CONFIG_WQ_CPU_INTENSIVE_REPORT +static unsigned int wq_cpu_intensive_warning_per_count =3D 4; +module_param_named(cpu_intensive_warning_per_count, wq_cpu_intensive_warni= ng_per_count, uint, 0644); +#endif =20 /* see the comment above the definition of WQ_POWER_EFFICIENT */ static bool wq_power_efficient =3D IS_ENABLED(CONFIG_WQ_POWER_EFFICIENT_DE= FAULT); @@ -1202,7 +1206,7 @@ static void wq_cpu_intensive_report(work_func_t func) * exponentially. */ cnt =3D atomic64_inc_return_relaxed(&ent->cnt); - if (cnt >=3D 4 && is_power_of_2(cnt)) + if (wq_cpu_intensive_warning_per_count && !(cnt % wq_cpu_intensive_warni= ng_per_count)) printk_deferred(KERN_WARNING "workqueue: %ps hogged CPU for >%luus %llu= times, consider switching to WQ_UNBOUND\n", ent->func, wq_cpu_intensive_thresh_us, atomic64_read(&ent->cnt)); @@ -1231,10 +1235,12 @@ static void wq_cpu_intensive_report(work_func_t fun= c) =20 ent =3D &wci_ents[wci_nr_ents++]; ent->func =3D func; - atomic64_set(&ent->cnt, 1); + atomic64_set(&ent->cnt, 0); hash_add_rcu(wci_hash, &ent->hash_node, (unsigned long)func); =20 raw_spin_unlock(&wci_lock); + + goto restart; } =20 #else /* CONFIG_WQ_CPU_INTENSIVE_REPORT */ --=20 2.25.1