watchdog/hardlockup/perf: Use new perf CPU enable mechanism (146c9d0e) · Commits · 戴 / test

kernel/watchdog.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -107,6 +107,7 @@ __setup("hardlockup_all_cpu_backtrace=", hardlockup_all_cpu_backtrace_setup);
		*/
		int __weak watchdog_nmi_enable(unsigned int cpu)
		{
		hardlockup_detector_perf_enable();
		return 0;
		}

		@@ -465,6 +466,7 @@ static void watchdog_enable(unsigned int cpu)
		/* Initialize timestamp */
		__touch_watchdog();
		/* Enable the perf event */
		if (watchdog_enabled & NMI_WATCHDOG_ENABLED)
		watchdog_nmi_enable(cpu);

		watchdog_set_prio(SCHED_FIFO, MAX_RT_PRIO - 1);

kernel/watchdog_hld.c

+5 −83

Original line number	Diff line number	Diff line
		@@ -25,7 +25,7 @@ static DEFINE_PER_CPU(struct perf_event *, dead_event);
		static struct cpumask dead_events_mask;

		static unsigned long hardlockup_allcpu_dumped;
		static bool hardlockup_detector_disabled;
		static unsigned int watchdog_cpus;

		void arch_touch_nmi_watchdog(void)
		{
		@@ -160,84 +160,6 @@ static void watchdog_overflow_callback(struct perf_event *event,
		return;
		}

		/*
		* People like the simple clean cpu node info on boot.
		* Reduce the watchdog noise by only printing messages
		* that are different from what cpu0 displayed.
		*/
		static unsigned long firstcpu_err;
		static atomic_t watchdog_cpus;

		int watchdog_nmi_enable(unsigned int cpu)
		{
		struct perf_event_attr *wd_attr;
		struct perf_event *event = per_cpu(watchdog_ev, cpu);
		int firstcpu = 0;

		/* nothing to do if the hard lockup detector is disabled */
		if (!(watchdog_enabled & NMI_WATCHDOG_ENABLED))
		goto out;

		/* A failure disabled the hardlockup detector permanently */
		if (hardlockup_detector_disabled)
		return -ENODEV;

		/* is it already setup and enabled? */
		if (event && event->state > PERF_EVENT_STATE_OFF)
		goto out;

		/* it is setup but not enabled */
		if (event != NULL)
		goto out_enable;

		if (atomic_inc_return(&watchdog_cpus) == 1)
		firstcpu = 1;

		wd_attr = &wd_hw_attr;
		wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh);

		/* Try to register using hardware perf events */
		event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback, NULL);

		/* save the first cpu's error for future comparision */
		if (firstcpu && IS_ERR(event))
		firstcpu_err = PTR_ERR(event);

		if (!IS_ERR(event)) {
		/* only print for the first cpu initialized */
		if (firstcpu \|\| firstcpu_err)
		pr_info("enabled on all CPUs, permanently consumes one hw-PMU counter.\n");
		goto out_save;
		}

		/* skip displaying the same error again */
		if (!firstcpu && (PTR_ERR(event) == firstcpu_err))
		return PTR_ERR(event);

		/* vary the KERN level based on the returned errno */
		if (PTR_ERR(event) == -EOPNOTSUPP)
		pr_info("disabled (cpu%i): not supported (no LAPIC?)\n", cpu);
		else if (PTR_ERR(event) == -ENOENT)
		pr_warn("disabled (cpu%i): hardware events not enabled\n",
		cpu);
		else
		pr_err("disabled (cpu%i): unable to create perf event: %ld\n",
		cpu, PTR_ERR(event));

		pr_info("Disabling hard lockup detector permanently\n");
		hardlockup_detector_disabled = true;

		return PTR_ERR(event);

		/* success path */
		out_save:
		per_cpu(watchdog_ev, cpu) = event;
		out_enable:
		perf_event_enable(per_cpu(watchdog_ev, cpu));
		out:
		return 0;
		}

		static int hardlockup_detector_event_create(void)
		{
		unsigned int cpu = smp_processor_id();
		@@ -267,6 +189,9 @@ void hardlockup_detector_perf_enable(void)
		if (hardlockup_detector_event_create())
		return;

		if (!watchdog_cpus++)
		pr_info("Enabled. Permanently consumes one hw-PMU counter.\n");

		perf_event_enable(this_cpu_read(watchdog_ev));
		}

		@@ -282,10 +207,7 @@ void hardlockup_detector_perf_disable(void)
		this_cpu_write(watchdog_ev, NULL);
		this_cpu_write(dead_event, event);
		cpumask_set_cpu(smp_processor_id(), &dead_events_mask);

		/* watchdog_nmi_enable() expects this to be zero initially. */
		if (atomic_dec_and_test(&watchdog_cpus))
		firstcpu_err = 0;
		watchdog_cpus--;
		}
		}

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