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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2010-12-08 15:29:02 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-12-08 20:16:31 +0100 |
| commit | c277443cfc29b1623b4923219ff0bdb48b91b589 (patch) | |
| tree | 0655516f81164a42dfb06e416b54c50cac33f433 | |
| parent | c079c791c5a0627fc7b752d31d72e274e0596ba8 (diff) | |
| download | linux-c277443cfc29b1623b4923219ff0bdb48b91b589.tar.bz2 | |
perf: Stop all counters on reboot
Use the reboot notifier to detach all running counters on reboot, this
solves a problem with kexec where the new kernel doesn't expect
running counters (rightly so).
It will however decrease the coverage of the NMI watchdog. Making a
kexec specific reboot notifier callback would be best, however that
would require touching all notifier callback handlers as they are not
properly structured to deal with new state.
As a compromise, place the perf reboot notifier at the very last
position in the list.
Reported-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Don Zickus <dzickus@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/perf_event.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 77ad22c00b9d..f9d2645b5546 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -21,6 +21,7 @@ #include <linux/dcache.h> #include <linux/percpu.h> #include <linux/ptrace.h> +#include <linux/reboot.h> #include <linux/vmstat.h> #include <linux/vmalloc.h> #include <linux/hardirq.h> @@ -6429,7 +6430,7 @@ static void __cpuinit perf_event_init_cpu(int cpu) mutex_unlock(&swhash->hlist_mutex); } -#ifdef CONFIG_HOTPLUG_CPU +#if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC static void perf_pmu_rotate_stop(struct pmu *pmu) { struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); @@ -6483,6 +6484,26 @@ static void perf_event_exit_cpu(int cpu) static inline void perf_event_exit_cpu(int cpu) { } #endif +static int +perf_reboot(struct notifier_block *notifier, unsigned long val, void *v) +{ + int cpu; + + for_each_online_cpu(cpu) + perf_event_exit_cpu(cpu); + + return NOTIFY_OK; +} + +/* + * Run the perf reboot notifier at the very last possible moment so that + * the generic watchdog code runs as long as possible. + */ +static struct notifier_block perf_reboot_notifier = { + .notifier_call = perf_reboot, + .priority = INT_MIN, +}; + static int __cpuinit perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { @@ -6518,6 +6539,7 @@ void __init perf_event_init(void) perf_pmu_register(&perf_task_clock); perf_tp_register(); perf_cpu_notifier(perf_cpu_notify); + register_reboot_notifier(&perf_reboot_notifier); ret = init_hw_breakpoint(); WARN(ret, "hw_breakpoint initialization failed with: %d", ret); |