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-rw-r--r--kernel/watchdog_hld.c25
1 files changed, 15 insertions, 10 deletions
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
index 12b8dd640786..b5de262a9eb9 100644
--- a/kernel/watchdog_hld.c
+++ b/kernel/watchdog_hld.c
@@ -137,12 +137,14 @@ static void watchdog_overflow_callback(struct perf_event *event,
* Reduce the watchdog noise by only printing messages
* that are different from what cpu0 displayed.
*/
-static unsigned long cpu0_err;
+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))
@@ -156,19 +158,22 @@ int watchdog_nmi_enable(unsigned int cpu)
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 cpu0 error for future comparision */
- if (cpu == 0 && IS_ERR(event))
- cpu0_err = PTR_ERR(event);
+ /* 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 cpu0 or different than cpu0 */
- if (cpu == 0 || cpu0_err)
+ /* 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;
}
@@ -186,7 +191,7 @@ int watchdog_nmi_enable(unsigned int cpu)
smp_mb__after_atomic();
/* skip displaying the same error again */
- if (cpu > 0 && (PTR_ERR(event) == cpu0_err))
+ if (!firstcpu && (PTR_ERR(event) == firstcpu_err))
return PTR_ERR(event);
/* vary the KERN level based on the returned errno */
@@ -222,9 +227,9 @@ void watchdog_nmi_disable(unsigned int cpu)
/* should be in cleanup, but blocks oprofile */
perf_event_release_kernel(event);
- }
- if (cpu == 0) {
+
/* watchdog_nmi_enable() expects this to be zero initially. */
- cpu0_err = 0;
+ if (atomic_dec_and_test(&watchdog_cpus))
+ firstcpu_err = 0;
}
}