From patchwork Fri Mar 7 02:18:10 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yicong Yang X-Patchwork-Id: 14005696 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 29C8CC282D1 for ; Fri, 7 Mar 2025 02:23:38 +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=ON6xK4tUoplLsWJ2JnviQP/r6hQ62Z7pTsiZtrYdS08=; b=stEZjPdp4vzWF/QJ0AYYKha1QZ DS79SAzhlxZSNJ2Ojhf2xQNodoieAOygOW65dMdnuGB/d7F6cQrZYufMOZ8738fdKxvkOGBKxCNNN t6iNzFr2Guc/H2KICr1kox/V61EalPgAFkC1GPIszceedE8eIs2nJDXL2N1ye5pQKBsl0IcC2RdPo aZvZW/unkFXIKlTvoVAPcpWXrdL2PODca2lY3tKzHjdfDYX0osNux1kHMpgKL9nrTfZcXZ2Er9ipf wF0hh8sQcf6uZvacJcsD+fJFfSNNqHpFs+nTnKv37wo/bAWu9Nxq90lCg4cp9n8wXvo45rKcyALta cF56BJoQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tqNN0-0000000Cttc-2jHE; Fri, 07 Mar 2025 02:23:26 +0000 Received: from szxga06-in.huawei.com ([45.249.212.32]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tqNID-0000000Ct5S-1sHf for linux-arm-kernel@lists.infradead.org; Fri, 07 Mar 2025 02:18:31 +0000 Received: from mail.maildlp.com (unknown [172.19.88.234]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4Z892G647zz17LVC; Fri, 7 Mar 2025 10:18:46 +0800 (CST) Received: from kwepemd200014.china.huawei.com (unknown [7.221.188.8]) by mail.maildlp.com (Postfix) with ESMTPS id D92241402C4; Fri, 7 Mar 2025 10:18:12 +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 1/2] watchdog/perf: Provide function for adjusting the event period Date: Fri, 7 Mar 2025 10:18:10 +0800 Message-ID: <20250307021811.46981-2-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_796384_655C627B X-CRM114-Status: GOOD ( 12.28 ) 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 Architecture's using perf events for hard lockup detection needs to convert the watchdog_thresh to the event's period, some architecture for example arm64 perform this conversion using the CPU's maximum frequency which will be acquired by cpufreq. However by the time the lockup detector's initialized the cpufreq driver may not be initialized, thus launch a watchdog with inaccurate period. Provide a function dhardlockup_detector_perf_adjust_period() to allowing adjust the event period. Then architecture can update with more accurate period if cpufreq is initialized. Signed-off-by: Yicong Yang --- include/linux/nmi.h | 2 ++ kernel/watchdog_perf.c | 21 +++++++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/include/linux/nmi.h b/include/linux/nmi.h index a8dfb38c9bb6..2200ce481439 100644 --- a/include/linux/nmi.h +++ b/include/linux/nmi.h @@ -106,11 +106,13 @@ extern void hardlockup_detector_perf_stop(void); extern void hardlockup_detector_perf_restart(void); extern void hardlockup_detector_perf_cleanup(void); extern void hardlockup_config_perf_event(const char *str); +extern void hardlockup_detector_perf_adjust_period(int cpu, u64 period); #else static inline void hardlockup_detector_perf_stop(void) { } static inline void hardlockup_detector_perf_restart(void) { } static inline void hardlockup_detector_perf_cleanup(void) { } static inline void hardlockup_config_perf_event(const char *str) { } +static inline void hardlockup_detector_perf_adjust_period(int cpu, u64 period) { } #endif void watchdog_hardlockup_stop(void); diff --git a/kernel/watchdog_perf.c b/kernel/watchdog_perf.c index 59c1d86a73a2..bc00985d1f69 100644 --- a/kernel/watchdog_perf.c +++ b/kernel/watchdog_perf.c @@ -211,6 +211,27 @@ void hardlockup_detector_perf_cleanup(void) cpumask_clear(&dead_events_mask); } +/** + * hardlockup_detector_perf_adjust_period - Adjust the events period due + * to cpu frequency change + */ +void hardlockup_detector_perf_adjust_period(int cpu, u64 period) +{ + struct perf_event *event = per_cpu(watchdog_ev, cpu); + + if (!(watchdog_enabled & WATCHDOG_HARDLOCKUP_ENABLED)) + return; + + if (!event) + return; + + if (event->attr.sample_period == period) + return; + + if (perf_event_period(event, period)) + pr_err("failed to change period to %llu\n", period); +} + /** * hardlockup_detector_perf_stop - Globally stop watchdog events * 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 ; 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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);