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[2001:1868:205::9]) by mx.google.com with ESMTPS id bd15si11163986pdb.71.2014.10.21.06.14.44 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 21 Oct 2014 06:14:45 -0700 (PDT) Received-SPF: none (google.com: linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org does not designate permitted sender hosts) client-ip=2001:1868:205::9; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1XgZFe-0000UQ-4q; Tue, 21 Oct 2014 13:13:26 +0000 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1XgZFK-0008QD-GD for linux-arm-kernel@lists.infradead.org; Tue, 21 Oct 2014 13:13:08 +0000 Received: from leverpostej.cambridge.arm.com (leverpostej.cambridge.arm.com [10.1.205.151]) by cam-admin0.cambridge.arm.com (8.12.6/8.12.6) with ESMTP id s9LDBfww016180; Tue, 21 Oct 2014 14:12:46 +0100 (BST) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 8/8] arm: perf: fold hotplug notifier into arm_pmu Date: Tue, 21 Oct 2014 14:11:24 +0100 Message-Id: <1413897084-19715-9-git-send-email-mark.rutland@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1413897084-19715-1-git-send-email-mark.rutland@arm.com> References: <1413897084-19715-1-git-send-email-mark.rutland@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141021_061306_901963_B1F060BC X-CRM114-Status: GOOD ( 18.18 ) X-Spam-Score: -6.4 (------) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (-6.4 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at http://www.dnswl.org/, high trust [217.140.96.50 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -1.4 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain Cc: Mark Rutland , pawel.moll@arm.com, sboyd@codeaurora.org, punit.agrawal@arm.com, will.deacon@arm.com, drew.richardson@arm.com X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: , List-Help: , List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org X-Removed-Original-Auth: Dkim didn't pass. X-Original-Sender: mark.rutland@arm.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.217.181 as permitted sender) smtp.mail=patch+caf_=patchwork-forward=linaro.org@linaro.org Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org X-Google-Group-Id: 836684582541 Handling multiple PMUs using a single hotplug notifier requires a list of PMUs to be maintained, with synchronisation in the probe, remove, and notify paths. This is error-prone and makes the code much harder to maintain. Instead of using a single notifier, we can dynamically allocate a notifier block per-PMU. The end result is the same, but the list of PMUs is implicit in the hotplug notifier list rather than within a perf-local data structure, which makes the code far easier to handle. Signed-off-by: Mark Rutland Reviewed-by: Will Deacon --- arch/arm/include/asm/pmu.h | 1 + arch/arm/kernel/perf_event_cpu.c | 66 +++++++++++++++++++--------------------- 2 files changed, 33 insertions(+), 34 deletions(-) diff --git a/arch/arm/include/asm/pmu.h b/arch/arm/include/asm/pmu.h index cc01498..b1596bd 100644 --- a/arch/arm/include/asm/pmu.h +++ b/arch/arm/include/asm/pmu.h @@ -116,6 +116,7 @@ struct arm_pmu { u64 max_period; struct platform_device *plat_device; struct pmu_hw_events __percpu *hw_events; + struct notifier_block hotplug_nb; }; #define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu)) diff --git a/arch/arm/kernel/perf_event_cpu.c b/arch/arm/kernel/perf_event_cpu.c index f8a237d..3095ca1 100644 --- a/arch/arm/kernel/perf_event_cpu.c +++ b/arch/arm/kernel/perf_event_cpu.c @@ -160,8 +160,31 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler) return 0; } +/* + * PMU hardware loses all context when a CPU goes offline. + * When a CPU is hotplugged back in, since some hardware registers are + * UNKNOWN at reset, the PMU must be explicitly reset to avoid reading + * junk values out of them. + */ +static int cpu_pmu_notify(struct notifier_block *b, unsigned long action, + void *hcpu) +{ + struct arm_pmu *pmu = container_of(b, struct arm_pmu, hotplug_nb); + + if ((action & ~CPU_TASKS_FROZEN) != CPU_STARTING) + return NOTIFY_DONE; + + if (pmu->reset) + pmu->reset(pmu); + else + return NOTIFY_DONE; + + return NOTIFY_OK; +} + static int cpu_pmu_init(struct arm_pmu *cpu_pmu) { + int err; int cpu; struct pmu_hw_events __percpu *cpu_hw_events; @@ -169,6 +192,11 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu) if (!cpu_hw_events) return -ENOMEM; + cpu_pmu->hotplug_nb.notifier_call = cpu_pmu_notify; + err = register_cpu_notifier(&cpu_pmu->hotplug_nb); + if (err) + goto out_hw_events; + for_each_possible_cpu(cpu) { struct pmu_hw_events *events = per_cpu_ptr(cpu_hw_events, cpu); raw_spin_lock_init(&events->pmu_lock); @@ -188,32 +216,12 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu) cpu_pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT; return 0; -} -/* - * PMU hardware loses all context when a CPU goes offline. - * When a CPU is hotplugged back in, since some hardware registers are - * UNKNOWN at reset, the PMU must be explicitly reset to avoid reading - * junk values out of them. - */ -static int cpu_pmu_notify(struct notifier_block *b, unsigned long action, - void *hcpu) -{ - if ((action & ~CPU_TASKS_FROZEN) != CPU_STARTING) - return NOTIFY_DONE; - - if (cpu_pmu && cpu_pmu->reset) - cpu_pmu->reset(cpu_pmu); - else - return NOTIFY_DONE; - - return NOTIFY_OK; +out_hw_events: + free_percpu(cpu_hw_events); + return err; } -static struct notifier_block cpu_pmu_hotplug_notifier = { - .notifier_call = cpu_pmu_notify, -}; - /* * PMU platform driver and devicetree bindings. */ @@ -336,16 +344,6 @@ static struct platform_driver cpu_pmu_driver = { static int __init register_pmu_driver(void) { - int err; - - err = register_cpu_notifier(&cpu_pmu_hotplug_notifier); - if (err) - return err; - - err = platform_driver_register(&cpu_pmu_driver); - if (err) - unregister_cpu_notifier(&cpu_pmu_hotplug_notifier); - - return err; + return platform_driver_register(&cpu_pmu_driver); } device_initcall(register_pmu_driver);