Commit 2508ce18 authored by Don Zickus's avatar Don Zickus Committed by Frederic Weisbecker
Browse files

lockup_detector: Remove old softlockup code 



Now that is no longer compiled or used, just remove it.

Also move some of the code wrapped with DETECT_SOFTLOCKUP to the
LOCKUP_DETECTOR wrappers because that is the code that uses it now.

Signed-off-by: default avatarDon Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <1273266711-18706-4-git-send-email-dzickus@redhat.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent 332fbdbc

kernel/softlockup.c

deleted100644 → 0
+0 −293
Original line number Diff line number Diff line 
/*

 * Detect Soft Lockups

 *

 * started by Ingo Molnar, Copyright (C) 2005, 2006 Red Hat, Inc.

 *

 * this code detects soft lockups: incidents in where on a CPU

 * the kernel does not reschedule for 10 seconds or more.

 */

#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/notifier.h>

#include <linux/module.h>

#include <linux/sysctl.h>



#include <asm/irq_regs.h>



static DEFINE_SPINLOCK(print_lock);



static DEFINE_PER_CPU(unsigned long, softlockup_touch_ts); /* touch timestamp */

static DEFINE_PER_CPU(unsigned long, softlockup_print_ts); /* print timestamp */

static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);

static DEFINE_PER_CPU(bool, softlock_touch_sync);



static int __read_mostly did_panic;

int __read_mostly softlockup_thresh = 60;



/*

 * Should we panic (and reboot, if panic_timeout= is set) when a

 * soft-lockup occurs:

 */

unsigned int __read_mostly softlockup_panic =

				CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE;



static int __init softlockup_panic_setup(char *str)

{

	softlockup_panic = simple_strtoul(str, NULL, 0);



	return 1;

}

__setup("softlockup_panic=", softlockup_panic_setup);



static int

softlock_panic(struct notifier_block *this, unsigned long event, void *ptr)

{

	did_panic = 1;



	return NOTIFY_DONE;

}



static struct notifier_block panic_block = {

	.notifier_call = softlock_panic,

};



/*

 * Returns seconds, approximately.  We don't need nanosecond

 * resolution, and we don't need to waste time with a big divide when

 * 2^30ns == 1.074s.

 */

static unsigned long get_timestamp(int this_cpu)

{

	return cpu_clock(this_cpu) >> 30LL;  /* 2^30 ~= 10^9 */

}



static void __touch_softlockup_watchdog(void)

{

	int this_cpu = raw_smp_processor_id();



	__raw_get_cpu_var(softlockup_touch_ts) = get_timestamp(this_cpu);

}



void touch_softlockup_watchdog(void)

{

	__raw_get_cpu_var(softlockup_touch_ts) = 0;

}

EXPORT_SYMBOL(touch_softlockup_watchdog);



void touch_softlockup_watchdog_sync(void)

{

	__raw_get_cpu_var(softlock_touch_sync) = true;

	__raw_get_cpu_var(softlockup_touch_ts) = 0;

}



void touch_all_softlockup_watchdogs(void)

{

	int cpu;



	/* Cause each CPU to re-update its timestamp rather than complain */

	for_each_online_cpu(cpu)

		per_cpu(softlockup_touch_ts, cpu) = 0;

}

EXPORT_SYMBOL(touch_all_softlockup_watchdogs);



int proc_dosoftlockup_thresh(struct ctl_table *table, int write,

			     void __user *buffer,

			     size_t *lenp, loff_t *ppos)

{

	touch_all_softlockup_watchdogs();

	return proc_dointvec_minmax(table, write, buffer, lenp, ppos);

}



/*

 * This callback runs from the timer interrupt, and checks

 * whether the watchdog thread has hung or not:

 */

void softlockup_tick(void)

{

	int this_cpu = smp_processor_id();

	unsigned long touch_ts = per_cpu(softlockup_touch_ts, this_cpu);

	unsigned long print_ts;

	struct pt_regs *regs = get_irq_regs();

	unsigned long now;



	/* Is detection switched off? */

	if (!per_cpu(softlockup_watchdog, this_cpu) || softlockup_thresh <= 0) {

		/* Be sure we don't false trigger if switched back on */

		if (touch_ts)

			per_cpu(softlockup_touch_ts, this_cpu) = 0;

		return;

	}



	if (touch_ts == 0) {

		if (unlikely(per_cpu(softlock_touch_sync, this_cpu))) {

			/*

			 * If the time stamp was touched atomically

			 * make sure the scheduler tick is up to date.

			 */

			per_cpu(softlock_touch_sync, this_cpu) = false;

			sched_clock_tick();

		}

		__touch_softlockup_watchdog();

		return;

	}



	print_ts = per_cpu(softlockup_print_ts, this_cpu);



	/* report at most once a second */

	if (print_ts == touch_ts || did_panic)

		return;



	/* do not print during early bootup: */

	if (unlikely(system_state != SYSTEM_RUNNING)) {

		__touch_softlockup_watchdog();

		return;

	}



	now = get_timestamp(this_cpu);



	/*

	 * Wake up the high-prio watchdog task twice per

	 * threshold timespan.

	 */

	if (time_after(now - softlockup_thresh/2, touch_ts))

		wake_up_process(per_cpu(softlockup_watchdog, this_cpu));



	/* Warn about unreasonable delays: */

	if (time_before_eq(now - softlockup_thresh, touch_ts))

		return;



	per_cpu(softlockup_print_ts, this_cpu) = touch_ts;



	spin_lock(&print_lock);

	printk(KERN_ERR "BUG: soft lockup - CPU#%d stuck for %lus! [%s:%d]\n",

			this_cpu, now - touch_ts,

			current->comm, task_pid_nr(current));

	print_modules();

	print_irqtrace_events(current);

	if (regs)

		show_regs(regs);

	else

		dump_stack();

	spin_unlock(&print_lock);



	if (softlockup_panic)

		panic("softlockup: hung tasks");

}



/*

 * 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 };



	sched_setscheduler(current, SCHED_FIFO, &param);



	/* initialize timestamp */

	__touch_softlockup_watchdog();



	set_current_state(TASK_INTERRUPTIBLE);

	/*

	 * Run briefly once per second to reset the softlockup timestamp.

	 * If this gets delayed for more than 60 seconds then the

	 * debug-printout triggers in softlockup_tick().

	 */

	while (!kthread_should_stop()) {

		__touch_softlockup_watchdog();

		schedule();



		if (kthread_should_stop())

			break;



		set_current_state(TASK_INTERRUPTIBLE);

	}

	__set_current_state(TASK_RUNNING);



	return 0;

}



/*

 * Create/destroy watchdog threads as CPUs come and go:

 */

static int __cpuinit

cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)

{

	int hotcpu = (unsigned long)hcpu;

	struct task_struct *p;



	switch (action) {

	case CPU_UP_PREPARE:

	case CPU_UP_PREPARE_FROZEN:

		BUG_ON(per_cpu(softlockup_watchdog, hotcpu));

		p = kthread_create(watchdog, hcpu, "watchdog/%d", hotcpu);

		if (IS_ERR(p)) {

			printk(KERN_ERR "watchdog for %i failed\n", hotcpu);

			return NOTIFY_BAD;

		}

		per_cpu(softlockup_touch_ts, hotcpu) = 0;

		per_cpu(softlockup_watchdog, hotcpu) = p;

		kthread_bind(p, hotcpu);

		break;

	case CPU_ONLINE:

	case CPU_ONLINE_FROZEN:

		wake_up_process(per_cpu(softlockup_watchdog, hotcpu));

		break;

#ifdef CONFIG_HOTPLUG_CPU

	case CPU_UP_CANCELED:

	case CPU_UP_CANCELED_FROZEN:

		if (!per_cpu(softlockup_watchdog, hotcpu))

			break;

		/* Unbind so it can run.  Fall thru. */

		kthread_bind(per_cpu(softlockup_watchdog, hotcpu),

			     cpumask_any(cpu_online_mask));

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:

		p = per_cpu(softlockup_watchdog, hotcpu);

		per_cpu(softlockup_watchdog, hotcpu) = NULL;

		kthread_stop(p);

		break;

#endif /* CONFIG_HOTPLUG_CPU */

	}

	return NOTIFY_OK;

}



static struct notifier_block __cpuinitdata cpu_nfb = {

	.notifier_call = cpu_callback

};



static int __initdata nosoftlockup;



static int __init nosoftlockup_setup(char *str)

{

	nosoftlockup = 1;

	return 1;

}

__setup("nosoftlockup", nosoftlockup_setup);



static int __init spawn_softlockup_task(void)

{

	void *cpu = (void *)(long)smp_processor_id();

	int err;



	if (nosoftlockup)

		return 0;



	err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);

	if (err == NOTIFY_BAD) {

		BUG();

		return 1;

	}

	cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);

	register_cpu_notifier(&cpu_nfb);



	atomic_notifier_chain_register(&panic_notifier_list, &panic_block);



	return 0;

}

early_initcall(spawn_softlockup_task);

kernel/sysctl.c

+10 −12
Original line number Diff line number Diff line
@@ -108,7 +108,7 @@ extern int blk_iopoll_enabled; 
#endif



/* Constants used for minimum and  maximum */

#ifdef CONFIG_DETECT_SOFTLOCKUP

#ifdef CONFIG_LOCKUP_DETECTOR

static int sixty = 60;

static int neg_one = -1;

#endif
@@ -703,6 +703,15 @@ static struct ctl_table kern_table[] = { 
		.extra1		= &neg_one,

		.extra2		= &sixty,

	},

	{

		.procname	= "softlockup_panic",

		.data		= &softlockup_panic,

		.maxlen		= sizeof(int),

		.mode		= 0644,

		.proc_handler	= proc_dointvec_minmax,

		.extra1		= &zero,

		.extra2		= &one,

	},

#endif

#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) && !defined(CONFIG_LOCKUP_DETECTOR)

	{
@@ -807,17 +816,6 @@ static struct ctl_table kern_table[] = { 
		.proc_handler	= proc_dointvec,

	},

#endif

#ifdef CONFIG_DETECT_SOFTLOCKUP

	{

		.procname	= "softlockup_panic",

		.data		= &softlockup_panic,

		.maxlen		= sizeof(int),

		.mode		= 0644,

		.proc_handler	= proc_dointvec_minmax,

		.extra1		= &zero,

		.extra2		= &one,

	},

#endif

#ifdef CONFIG_DETECT_HUNG_TASK

	{

		.procname	= "hung_task_panic",

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