diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/exit.c | 2 | ||||
| -rw-r--r-- | kernel/smpboot.c | 60 | ||||
| -rw-r--r-- | kernel/sysctl.c | 7 | ||||
| -rw-r--r-- | kernel/watchdog.c | 67 |
4 files changed, 129 insertions, 7 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 22fcc05dec40..185752a729f6 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -436,7 +436,7 @@ static void exit_mm(struct task_struct *tsk) mm_update_next_owner(mm); mmput(mm); if (test_thread_flag(TIF_MEMDIE)) - unmark_oom_victim(); + exit_oom_victim(); } static struct task_struct *find_alive_thread(struct task_struct *p) diff --git a/kernel/smpboot.c b/kernel/smpboot.c index c697f73d82d6..7c434c39f02a 100644 --- a/kernel/smpboot.c +++ b/kernel/smpboot.c @@ -232,7 +232,8 @@ void smpboot_unpark_threads(unsigned int cpu) mutex_lock(&smpboot_threads_lock); list_for_each_entry(cur, &hotplug_threads, list) - smpboot_unpark_thread(cur, cpu); + if (cpumask_test_cpu(cpu, cur->cpumask)) + smpboot_unpark_thread(cur, cpu); mutex_unlock(&smpboot_threads_lock); } @@ -258,6 +259,15 @@ static void smpboot_destroy_threads(struct smp_hotplug_thread *ht) { unsigned int cpu; + /* Unpark any threads that were voluntarily parked. */ + for_each_cpu_not(cpu, ht->cpumask) { + if (cpu_online(cpu)) { + struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu); + if (tsk) + kthread_unpark(tsk); + } + } + /* We need to destroy also the parked threads of offline cpus */ for_each_possible_cpu(cpu) { struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu); @@ -281,6 +291,10 @@ int smpboot_register_percpu_thread(struct smp_hotplug_thread *plug_thread) unsigned int cpu; int ret = 0; + if (!alloc_cpumask_var(&plug_thread->cpumask, GFP_KERNEL)) + return -ENOMEM; + cpumask_copy(plug_thread->cpumask, cpu_possible_mask); + get_online_cpus(); mutex_lock(&smpboot_threads_lock); for_each_online_cpu(cpu) { @@ -313,9 +327,53 @@ void smpboot_unregister_percpu_thread(struct smp_hotplug_thread *plug_thread) smpboot_destroy_threads(plug_thread); mutex_unlock(&smpboot_threads_lock); put_online_cpus(); + free_cpumask_var(plug_thread->cpumask); } EXPORT_SYMBOL_GPL(smpboot_unregister_percpu_thread); +/** + * smpboot_update_cpumask_percpu_thread - Adjust which per_cpu hotplug threads stay parked + * @plug_thread: Hotplug thread descriptor + * @new: Revised mask to use + * + * 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) +{ + struct cpumask *old = plug_thread->cpumask; + cpumask_var_t tmp; + unsigned int cpu; + + if (!alloc_cpumask_var(&tmp, GFP_KERNEL)) + return -ENOMEM; + + get_online_cpus(); + mutex_lock(&smpboot_threads_lock); + + /* Park threads that were exclusively enabled on the old mask. */ + cpumask_andnot(tmp, old, new); + for_each_cpu_and(cpu, tmp, cpu_online_mask) + smpboot_park_thread(plug_thread, cpu); + + /* Unpark threads that are exclusively enabled on the new mask. */ + cpumask_andnot(tmp, new, old); + for_each_cpu_and(cpu, tmp, cpu_online_mask) + smpboot_unpark_thread(plug_thread, cpu); + + cpumask_copy(old, new); + + mutex_unlock(&smpboot_threads_lock); + put_online_cpus(); + + free_cpumask_var(tmp); + + return 0; +} +EXPORT_SYMBOL_GPL(smpboot_update_cpumask_percpu_thread); + static DEFINE_PER_CPU(atomic_t, cpu_hotplug_state) = ATOMIC_INIT(CPU_POST_DEAD); /* 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(); } |