From patchwork Mon Oct 27 12:06:39 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 5159851 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id F3A069F318 for ; Mon, 27 Oct 2014 12:11:37 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 0C4EF201BB for ; Mon, 27 Oct 2014 12:11:37 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 198812017E for ; Mon, 27 Oct 2014 12:11:36 +0000 (UTC) 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 1Xij77-0007wC-Tw; Mon, 27 Oct 2014 12:09:33 +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 1Xij6E-00071y-E9 for linux-arm-kernel@lists.infradead.org; Mon, 27 Oct 2014 12:08:40 +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 s9RC6owx022943; Mon, 27 Oct 2014 12:08:17 GMT From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Subject: [PATCHv2 9/9] arm: perf: fold hotplug notifier into arm_pmu Date: Mon, 27 Oct 2014 12:06:39 +0000 Message-Id: <1414411599-1938-10-git-send-email-mark.rutland@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1414411599-1938-1-git-send-email-mark.rutland@arm.com> References: <1414411599-1938-1-git-send-email-mark.rutland@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141027_050838_840293_88330AFC X-CRM114-Status: GOOD ( 17.53 ) X-Spam-Score: -5.6 (-----) Cc: Mark Rutland , pawel.moll@arm.com, will.deacon@arm.com, punit.agrawal@arm.com, sboyd@codeaurora.org, 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+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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: Stephen Boyd --- arch/arm/include/asm/pmu.h | 1 + arch/arm/kernel/perf_event_cpu.c | 69 ++++++++++++++++++++-------------------- 2 files changed, 35 insertions(+), 35 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 6e550cf..4a70f94 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); @@ -188,38 +216,19 @@ static int cpu_pmu_init(struct arm_pmu *cpu_pmu) cpu_pmu->pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT; return 0; + +out_hw_events: + free_percpu(cpu_hw_events); + return err; } static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu) { free_percpu(cpu_pmu->hw_events); + unregister_cpu_notifier(&cpu_pmu->hotplug_nb); } /* - * 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; -} - -static struct notifier_block cpu_pmu_hotplug_notifier = { - .notifier_call = cpu_pmu_notify, -}; - -/* * PMU platform driver and devicetree bindings. */ static struct of_device_id cpu_pmu_of_device_ids[] = { @@ -344,16 +353,6 @@ 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);