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Diffstat (limited to 'kernel/watchdog.c')
-rw-r--r--kernel/watchdog.c67
1 files changed, 62 insertions, 5 deletions
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 581a68a04c64..a6ffa43f2993 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -19,6 +19,7 @@
#include <linux/sysctl.h>
#include <linux/smpboot.h>
#include <linux/sched/rt.h>
+#include <linux/tick.h>
#include <asm/irq_regs.h>
#include <linux/kvm_para.h>
@@ -58,6 +59,12 @@ int __read_mostly sysctl_softlockup_all_cpu_backtrace;
#else
#define sysctl_softlockup_all_cpu_backtrace 0
#endif
+static struct cpumask watchdog_cpumask __read_mostly;
+unsigned long *watchdog_cpumask_bits = cpumask_bits(&watchdog_cpumask);
+
+/* Helper for online, unparked cpus. */
+#define for_each_watchdog_cpu(cpu) \
+ for_each_cpu_and((cpu), cpu_online_mask, &watchdog_cpumask)
static int __read_mostly watchdog_running;
static u64 __read_mostly sample_period;
@@ -207,7 +214,7 @@ void touch_all_softlockup_watchdogs(void)
* do we care if a 0 races with a timestamp?
* all it means is the softlock check starts one cycle later
*/
- for_each_online_cpu(cpu)
+ for_each_watchdog_cpu(cpu)
per_cpu(watchdog_touch_ts, cpu) = 0;
}
@@ -616,7 +623,7 @@ void watchdog_nmi_enable_all(void)
goto unlock;
get_online_cpus();
- for_each_online_cpu(cpu)
+ for_each_watchdog_cpu(cpu)
watchdog_nmi_enable(cpu);
put_online_cpus();
@@ -634,7 +641,7 @@ void watchdog_nmi_disable_all(void)
goto unlock;
get_online_cpus();
- for_each_online_cpu(cpu)
+ for_each_watchdog_cpu(cpu)
watchdog_nmi_disable(cpu);
put_online_cpus();
@@ -696,7 +703,7 @@ static void update_watchdog_all_cpus(void)
int cpu;
get_online_cpus();
- for_each_online_cpu(cpu)
+ for_each_watchdog_cpu(cpu)
update_watchdog(cpu);
put_online_cpus();
}
@@ -709,8 +716,12 @@ static int watchdog_enable_all_cpus(void)
err = smpboot_register_percpu_thread(&watchdog_threads);
if (err)
pr_err("Failed to create watchdog threads, disabled\n");
- else
+ else {
+ if (smpboot_update_cpumask_percpu_thread(
+ &watchdog_threads, &watchdog_cpumask))
+ pr_err("Failed to set cpumask for watchdog threads\n");
watchdog_running = 1;
+ }
} else {
/*
* Enable/disable the lockup detectors or
@@ -879,12 +890,58 @@ out:
mutex_unlock(&watchdog_proc_mutex);
return err;
}
+
+/*
+ * The cpumask is the mask of possible cpus that the watchdog can run
+ * on, not the mask of cpus it is actually running on. This allows the
+ * user to specify a mask that will include cpus that have not yet
+ * been brought online, if desired.
+ */
+int proc_watchdog_cpumask(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ int err;
+
+ mutex_lock(&watchdog_proc_mutex);
+ err = proc_do_large_bitmap(table, write, buffer, lenp, ppos);
+ if (!err && write) {
+ /* Remove impossible cpus to keep sysctl output cleaner. */
+ cpumask_and(&watchdog_cpumask, &watchdog_cpumask,
+ cpu_possible_mask);
+
+ if (watchdog_running) {
+ /*
+ * Failure would be due to being unable to allocate
+ * a temporary cpumask, so we are likely not in a
+ * position to do much else to make things better.
+ */
+ if (smpboot_update_cpumask_percpu_thread(
+ &watchdog_threads, &watchdog_cpumask) != 0)
+ pr_err("cpumask update failed\n");
+ }
+ }
+ mutex_unlock(&watchdog_proc_mutex);
+ return err;
+}
+
#endif /* CONFIG_SYSCTL */
void __init lockup_detector_init(void)
{
set_sample_period();
+#ifdef CONFIG_NO_HZ_FULL
+ if (tick_nohz_full_enabled()) {
+ if (!cpumask_empty(tick_nohz_full_mask))
+ pr_info("Disabling watchdog on nohz_full cores by default\n");
+ cpumask_andnot(&watchdog_cpumask, cpu_possible_mask,
+ tick_nohz_full_mask);
+ } else
+ cpumask_copy(&watchdog_cpumask, cpu_possible_mask);
+#else
+ cpumask_copy(&watchdog_cpumask, cpu_possible_mask);
+#endif
+
if (watchdog_enabled)
watchdog_enable_all_cpus();
}