diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/smpboot.c | 1 | ||||
| -rw-r--r-- | kernel/sysctl.c | 7 | ||||
| -rw-r--r-- | kernel/watchdog.c | 67 |
3 files changed, 70 insertions, 5 deletions
diff --git a/kernel/smpboot.c b/kernel/smpboot.c index 5e46c2a75d59..7c434c39f02a 100644 --- a/kernel/smpboot.c +++ b/kernel/smpboot.c @@ -338,6 +338,7 @@ EXPORT_SYMBOL_GPL(smpboot_unregister_percpu_thread); * * The cpumask field in the smp_hotplug_thread must not be updated directly * by the client, but only by calling this function. + * This function can only be called on a registered smp_hotplug_thread. */ int smpboot_update_cpumask_percpu_thread(struct smp_hotplug_thread *plug_thread, const struct cpumask *new) diff --git a/kernel/sysctl.c b/kernel/sysctl.c index b13e9d2de302..812fcc3fd390 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -872,6 +872,13 @@ static struct ctl_table kern_table[] = { .extra2 = &one, }, { + .procname = "watchdog_cpumask", + .data = &watchdog_cpumask_bits, + .maxlen = NR_CPUS, + .mode = 0644, + .proc_handler = proc_watchdog_cpumask, + }, + { .procname = "softlockup_panic", .data = &softlockup_panic, .maxlen = sizeof(int), 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(); } |