Merge branch 'core/softlockup' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip (1551260d) · Commits · 戴 / test

include/linux/sched.h

+10 −8

Original line number	Diff line number	Diff line
		@@ -300,17 +300,11 @@ extern int proc_dosoftlockup_thresh(struct ctl_table *table, int write,
		struct file filp, void __user buffer,
		size_t lenp, loff_t ppos);
		extern unsigned int softlockup_panic;
		extern unsigned long sysctl_hung_task_check_count;
		extern unsigned long sysctl_hung_task_timeout_secs;
		extern unsigned long sysctl_hung_task_warnings;
		extern int softlockup_thresh;
		#else
		static inline void softlockup_tick(void)
		{
		}
		static inline void spawn_softlockup_task(void)
		{
		}
		static inline void touch_softlockup_watchdog(void)
		{
		}
		@@ -319,6 +313,15 @@ static inline void touch_all_softlockup_watchdogs(void)
		}
		#endif

		#ifdef CONFIG_DETECT_HUNG_TASK
		extern unsigned int sysctl_hung_task_panic;
		extern unsigned long sysctl_hung_task_check_count;
		extern unsigned long sysctl_hung_task_timeout_secs;
		extern unsigned long sysctl_hung_task_warnings;
		extern int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
		struct file filp, void __user buffer,
		size_t lenp, loff_t ppos);
		#endif

		/* Attach to any functions which should be ignored in wchan output. */
		#define __sched __attribute__((__section__(".sched.text")))
		@@ -1255,9 +1258,8 @@ struct task_struct {
		/* ipc stuff */
		struct sysv_sem sysvsem;
		#endif
		#ifdef CONFIG_DETECT_SOFTLOCKUP
		#ifdef CONFIG_DETECT_HUNG_TASK
		/* hung task detection */
		unsigned long last_switch_timestamp;
		unsigned long last_switch_count;
		#endif
		/* CPU-specific state of this task */

kernel/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -74,6 +74,7 @@ obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
		obj-$(CONFIG_KPROBES) += kprobes.o
		obj-$(CONFIG_KGDB) += kgdb.o
		obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
		obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
		obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
		obj-$(CONFIG_SECCOMP) += seccomp.o
		obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o

kernel/fork.c

+3 −5

Original line number	Diff line number	Diff line
		@@ -645,6 +645,9 @@ static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)

		tsk->min_flt = tsk->maj_flt = 0;
		tsk->nvcsw = tsk->nivcsw = 0;
		#ifdef CONFIG_DETECT_HUNG_TASK
		tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw;
		#endif

		tsk->mm = NULL;
		tsk->active_mm = NULL;
		@@ -1032,11 +1035,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,

		p->default_timer_slack_ns = current->timer_slack_ns;

		#ifdef CONFIG_DETECT_SOFTLOCKUP
		p->last_switch_count = 0;
		p->last_switch_timestamp = 0;
		#endif

		task_io_accounting_init(&p->ioac);
		acct_clear_integrals(p);

kernel/hung_task.c

0 → 100644

+217 −0

Original line number	Diff line number	Diff line
		/*
		* Detect Hung Task
		*
		* kernel/hung_task.c - kernel thread for detecting tasks stuck in D state
		*
		*/

		#include <linux/mm.h>
		#include <linux/cpu.h>
		#include <linux/nmi.h>
		#include <linux/init.h>
		#include <linux/delay.h>
		#include <linux/freezer.h>
		#include <linux/kthread.h>
		#include <linux/lockdep.h>
		#include <linux/module.h>
		#include <linux/sysctl.h>

		/*
		* The number of tasks checked:
		*/
		unsigned long __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;

		/*
		* Limit number of tasks checked in a batch.
		*
		* This value controls the preemptibility of khungtaskd since preemption
		* is disabled during the critical section. It also controls the size of
		* the RCU grace period. So it needs to be upper-bound.
		*/
		#define HUNG_TASK_BATCHING 1024

		/*
		* Zero means infinite timeout - no checking done:
		*/
		unsigned long __read_mostly sysctl_hung_task_timeout_secs = 120;

		unsigned long __read_mostly sysctl_hung_task_warnings = 10;

		static int __read_mostly did_panic;

		static struct task_struct *watchdog_task;

		/*
		* Should we panic (and reboot, if panic_timeout= is set) when a
		* hung task is detected:
		*/
		unsigned int __read_mostly sysctl_hung_task_panic =
		CONFIG_BOOTPARAM_HUNG_TASK_PANIC_VALUE;

		static int __init hung_task_panic_setup(char *str)
		{
		sysctl_hung_task_panic = simple_strtoul(str, NULL, 0);

		return 1;
		}
		__setup("hung_task_panic=", hung_task_panic_setup);

		static int
		hung_task_panic(struct notifier_block this, unsigned long event, void ptr)
		{
		did_panic = 1;

		return NOTIFY_DONE;
		}

		static struct notifier_block panic_block = {
		.notifier_call = hung_task_panic,
		};

		static void check_hung_task(struct task_struct *t, unsigned long timeout)
		{
		unsigned long switch_count = t->nvcsw + t->nivcsw;

		/*
		* Ensure the task is not frozen.
		* Also, when a freshly created task is scheduled once, changes
		* its state to TASK_UNINTERRUPTIBLE without having ever been
		* switched out once, it musn't be checked.
		*/
		if (unlikely(t->flags & PF_FROZEN \|\| !switch_count))
		return;

		if (switch_count != t->last_switch_count) {
		t->last_switch_count = switch_count;
		return;
		}
		if (!sysctl_hung_task_warnings)
		return;
		sysctl_hung_task_warnings--;

		/*
		* Ok, the task did not get scheduled for more than 2 minutes,
		* complain:
		*/
		printk(KERN_ERR "INFO: task %s:%d blocked for more than "
		"%ld seconds.\n", t->comm, t->pid, timeout);
		printk(KERN_ERR "\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\""
		" disables this message.\n");
		sched_show_task(t);
		__debug_show_held_locks(t);

		touch_nmi_watchdog();

		if (sysctl_hung_task_panic)
		panic("hung_task: blocked tasks");
		}

		/*
		* To avoid extending the RCU grace period for an unbounded amount of time,
		* periodically exit the critical section and enter a new one.
		*
		* For preemptible RCU it is sufficient to call rcu_read_unlock in order
		* exit the grace period. For classic RCU, a reschedule is required.
		*/
		static void rcu_lock_break(struct task_struct g, struct task_struct t)
		{
		get_task_struct(g);
		get_task_struct(t);
		rcu_read_unlock();
		cond_resched();
		rcu_read_lock();
		put_task_struct(t);
		put_task_struct(g);
		}

		/*
		* Check whether a TASK_UNINTERRUPTIBLE does not get woken up for
		* a really long time (120 seconds). If that happens, print out
		* a warning.
		*/
		static void check_hung_uninterruptible_tasks(unsigned long timeout)
		{
		int max_count = sysctl_hung_task_check_count;
		int batch_count = HUNG_TASK_BATCHING;
		struct task_struct g, t;

		/*
		* If the system crashed already then all bets are off,
		* do not report extra hung tasks:
		*/
		if (test_taint(TAINT_DIE) \|\| did_panic)
		return;

		rcu_read_lock();
		do_each_thread(g, t) {
		if (!--max_count)
		goto unlock;
		if (!--batch_count) {
		batch_count = HUNG_TASK_BATCHING;
		rcu_lock_break(g, t);
		/* Exit if t or g was unhashed during refresh. */
		if (t->state == TASK_DEAD \|\| g->state == TASK_DEAD)
		goto unlock;
		}
		/* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */
		if (t->state == TASK_UNINTERRUPTIBLE)
		check_hung_task(t, timeout);
		} while_each_thread(g, t);
		unlock:
		rcu_read_unlock();
		}

		static unsigned long timeout_jiffies(unsigned long timeout)
		{
		/* timeout of 0 will disable the watchdog */
		return timeout ? timeout * HZ : MAX_SCHEDULE_TIMEOUT;
		}

		/*
		* Process updating of timeout sysctl
		*/
		int proc_dohung_task_timeout_secs(struct ctl_table *table, int write,
		struct file filp, void __user buffer,
		size_t lenp, loff_t ppos)
		{
		int ret;

		ret = proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos);

		if (ret \|\| !write)
		goto out;

		wake_up_process(watchdog_task);

		out:
		return ret;
		}

		/*
		* kthread which checks for tasks stuck in D state
		*/
		static int watchdog(void *dummy)
		{
		set_user_nice(current, 0);

		for ( ; ; ) {
		unsigned long timeout = sysctl_hung_task_timeout_secs;

		while (schedule_timeout_interruptible(timeout_jiffies(timeout)))
		timeout = sysctl_hung_task_timeout_secs;

		check_hung_uninterruptible_tasks(timeout);
		}

		return 0;
		}

		static int __init hung_task_init(void)
		{
		atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
		watchdog_task = kthread_run(watchdog, NULL, "khungtaskd");

		return 0;
		}

		module_init(hung_task_init);

kernel/softlockup.c

+0 −100

Original line number	Diff line number	Diff line
		@@ -165,98 +165,12 @@ void softlockup_tick(void)
		panic("softlockup: hung tasks");
		}

		/*
		* Have a reasonable limit on the number of tasks checked:
		*/
		unsigned long __read_mostly sysctl_hung_task_check_count = 1024;

		/*
		* Zero means infinite timeout - no checking done:
		*/
		unsigned long __read_mostly sysctl_hung_task_timeout_secs = 480;

		unsigned long __read_mostly sysctl_hung_task_warnings = 10;

		/*
		* Only do the hung-tasks check on one CPU:
		*/
		static int check_cpu __read_mostly = -1;

		static void check_hung_task(struct task_struct *t, unsigned long now)
		{
		unsigned long switch_count = t->nvcsw + t->nivcsw;

		if (t->flags & PF_FROZEN)
		return;

		if (switch_count != t->last_switch_count \|\| !t->last_switch_timestamp) {
		t->last_switch_count = switch_count;
		t->last_switch_timestamp = now;
		return;
		}
		if ((long)(now - t->last_switch_timestamp) <
		sysctl_hung_task_timeout_secs)
		return;
		if (!sysctl_hung_task_warnings)
		return;
		sysctl_hung_task_warnings--;

		/*
		* Ok, the task did not get scheduled for more than 2 minutes,
		* complain:
		*/
		printk(KERN_ERR "INFO: task %s:%d blocked for more than "
		"%ld seconds.\n", t->comm, t->pid,
		sysctl_hung_task_timeout_secs);
		printk(KERN_ERR "\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\""
		" disables this message.\n");
		sched_show_task(t);
		__debug_show_held_locks(t);

		t->last_switch_timestamp = now;
		touch_nmi_watchdog();

		if (softlockup_panic)
		panic("softlockup: blocked tasks");
		}

		/*
		* Check whether a TASK_UNINTERRUPTIBLE does not get woken up for
		* a really long time (120 seconds). If that happens, print out
		* a warning.
		*/
		static void check_hung_uninterruptible_tasks(int this_cpu)
		{
		int max_count = sysctl_hung_task_check_count;
		unsigned long now = get_timestamp(this_cpu);
		struct task_struct g, t;

		/*
		* If the system crashed already then all bets are off,
		* do not report extra hung tasks:
		*/
		if (test_taint(TAINT_DIE) \|\| did_panic)
		return;

		read_lock(&tasklist_lock);
		do_each_thread(g, t) {
		if (!--max_count)
		goto unlock;
		/* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */
		if (t->state == TASK_UNINTERRUPTIBLE)
		check_hung_task(t, now);
		} while_each_thread(g, t);
		unlock:
		read_unlock(&tasklist_lock);
		}

		/*
		* The watchdog thread - runs every second and touches the timestamp.
		*/
		static int watchdog(void *__bind_cpu)
		{
		struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
		int this_cpu = (long)__bind_cpu;

		sched_setscheduler(current, SCHED_FIFO, &param);

		@@ -276,11 +190,6 @@ static int watchdog(void *__bind_cpu)
		if (kthread_should_stop())
		break;

		if (this_cpu == check_cpu) {
		if (sysctl_hung_task_timeout_secs)
		check_hung_uninterruptible_tasks(this_cpu);
		}

		set_current_state(TASK_INTERRUPTIBLE);
		}
		__set_current_state(TASK_RUNNING);
		@@ -312,18 +221,9 @@ cpu_callback(struct notifier_block nfb, unsigned long action, void hcpu)
		break;
		case CPU_ONLINE:
		case CPU_ONLINE_FROZEN:
		check_cpu = cpumask_any(cpu_online_mask);
		wake_up_process(per_cpu(watchdog_task, hotcpu));
		break;
		#ifdef CONFIG_HOTPLUG_CPU
		case CPU_DOWN_PREPARE:
		case CPU_DOWN_PREPARE_FROZEN:
		if (hotcpu == check_cpu) {
		/* Pick any other online cpu. */
		check_cpu = cpumask_any_but(cpu_online_mask, hotcpu);
		}
		break;

		case CPU_UP_CANCELED:
		case CPU_UP_CANCELED_FROZEN:
		if (!per_cpu(watchdog_task, hotcpu))

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