From patchwork Fri Mar 7 02:18:11 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yicong Yang X-Patchwork-Id: 14005695 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C98EFC282D1 for ; Fri, 7 Mar 2025 02:21:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=F2z+wpsgIjye+L/TqgA2F57y2cThaXV5OWwPz6rQYxI=; b=ABLvksP9AiwJY4VsawArkHPUSt cnW7hnG83CVD4kUv1+xzY/gLFASes1BUGv4Gd5O9Oug10egrH8n615xUAQbRbV7FTDOSd4A/ayAQI 6kaDA8SaJbjyicUqRTyBtOx2eyYpWXv+HjA9BJQIevR5EDU8HkfI6syNwEfQ/u6SYF14burn318vs MuldTeQBKlONxfWGPUNwlrhpSeL2PptUIARP/D8BdAYUk9MaeI9VFYqKSuZxtcjQV6YivNhAacPjT m8Nki54jr2e6elui01/9dqUEjJq1VBB+NmWU3mjP0K3gRveJyoR3voCB612yJBwPfZIzEeH+hpPzT rrxmVqaw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tqNLP-0000000Ctkf-45YH; Fri, 07 Mar 2025 02:21:47 +0000 Received: from szxga01-in.huawei.com ([45.249.212.187]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tqNID-0000000Ct5T-1F1L for linux-arm-kernel@lists.infradead.org; Fri, 07 Mar 2025 02:18:30 +0000 Received: from mail.maildlp.com (unknown [172.19.88.105]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Z88xF1fpwzvWrr; Fri, 7 Mar 2025 10:14:25 +0800 (CST) Received: from kwepemd200014.china.huawei.com (unknown [7.221.188.8]) by mail.maildlp.com (Postfix) with ESMTPS id 6DE9C140257; Fri, 7 Mar 2025 10:18:13 +0800 (CST) Received: from localhost.localdomain (10.50.165.33) by kwepemd200014.china.huawei.com (7.221.188.8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.34; Fri, 7 Mar 2025 10:18:12 +0800 From: Yicong Yang To: , , , , , , , , , CC: , , , , Subject: [PATCH 2/2] arm64/watchdog_hld: Add a cpufreq notifier for update watchdog thresh Date: Fri, 7 Mar 2025 10:18:11 +0800 Message-ID: <20250307021811.46981-3-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20250307021811.46981-1-yangyicong@huawei.com> References: <20250307021811.46981-1-yangyicong@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.50.165.33] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To kwepemd200014.china.huawei.com (7.221.188.8) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250306_181829_517252_4327B884 X-CRM114-Status: GOOD ( 12.21 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Yicong Yang arm64 depends on the cpufreq driver to gain the maximum cpu frequency to convert the watchdog_thresh to perf event period. cpufreq drivers like cppc_cpufreq will be initialized lately after the initializing of the hard lockup detector so just use a safe cpufreq which will be inaccurency. Use a cpufreq notifier to adjust the event's period to a more accurate one. Signed-off-by: Yicong Yang --- arch/arm64/kernel/watchdog_hld.c | 34 ++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/arch/arm64/kernel/watchdog_hld.c b/arch/arm64/kernel/watchdog_hld.c index dcd25322127c..719ae39e8bc0 100644 --- a/arch/arm64/kernel/watchdog_hld.c +++ b/arch/arm64/kernel/watchdog_hld.c @@ -34,3 +34,37 @@ bool __init arch_perf_nmi_is_available(void) */ return arm_pmu_irq_is_nmi(); } + +static int watchdog_freq_notifier_callback(struct notifier_block *nb, + unsigned long val, void *data) +{ + struct cpufreq_policy *policy = data; + unsigned long max_cpu_freq; + u64 new_period; + int cpu; + + if (val != CPUFREQ_CREATE_POLICY) + return 0; + + for_each_cpu(cpu, policy->cpus) { + max_cpu_freq = cpufreq_get_hw_max_freq(cpu) * 1000UL; + if (!max_cpu_freq) + continue; + + new_period = watchdog_thresh * max_cpu_freq; + hardlockup_detector_perf_adjust_period(cpu, new_period); + } + + return 0; +} + +static struct notifier_block watchdog_freq_notifier = { + .notifier_call = watchdog_freq_notifier_callback, +}; + +static int __init init_watchdog_freq_notifier(void) +{ + return cpufreq_register_notifier(&watchdog_freq_notifier, + CPUFREQ_POLICY_NOTIFIER); +} +core_initcall(init_watchdog_freq_notifier);