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Commit 3c00ea82 authored by Frederic Weisbecker's avatar Frederic Weisbecker
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watchdog: Rename confusing state variable 



We have two very conflicting state variable names in the
watchdog:

* watchdog_enabled: This one reflects the user interface. It's
set to 1 by default and can be overriden with boot options
or sysctl/procfs interface.

* watchdog_disabled: This is the internal toggle state that
tells if watchdog threads, timers and NMI events are currently
running or not. This state mostly depends on the user settings.
It's a convenient state latch.

Now we really need to find clearer names because those
are just too confusing to encourage deep review.

watchdog_enabled now becomes watchdog_user_enabled to reflect
its purpose as an interface.

watchdog_disabled becomes watchdog_running to suggest its
role as a pure internal state.

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Anish Singh <anish198519851985@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Don Zickus <dzickus@redhat.com>
parent b8900bc0

include/linux/nmi.h

+1 −1
Original line number Diff line number Diff line
@@ -46,7 +46,7 @@ static inline bool trigger_all_cpu_backtrace(void) 
#ifdef CONFIG_LOCKUP_DETECTOR

int hw_nmi_is_cpu_stuck(struct pt_regs *);

u64 hw_nmi_get_sample_period(int watchdog_thresh);

extern int watchdog_enabled;

extern int watchdog_user_enabled;

extern int watchdog_thresh;

struct ctl_table;

extern int proc_dowatchdog(struct ctl_table *, int ,

kernel/sysctl.c

+2 −2
Original line number Diff line number Diff line
@@ -801,7 +801,7 @@ static struct ctl_table kern_table[] = { 
#if defined(CONFIG_LOCKUP_DETECTOR)

	{

		.procname       = "watchdog",

		.data           = &watchdog_enabled,

		.data           = &watchdog_user_enabled,

		.maxlen         = sizeof (int),

		.mode           = 0644,

		.proc_handler   = proc_dowatchdog,
@@ -828,7 +828,7 @@ static struct ctl_table kern_table[] = { 
	},

	{

		.procname       = "nmi_watchdog",

		.data           = &watchdog_enabled,

		.data           = &watchdog_user_enabled,

		.maxlen         = sizeof (int),

		.mode           = 0644,

		.proc_handler   = proc_dowatchdog,

kernel/watchdog.c

+15 −15
Original line number Diff line number Diff line
@@ -29,9 +29,9 @@ 
#include <linux/kvm_para.h>

#include <linux/perf_event.h>



int watchdog_enabled = 1;

int watchdog_user_enabled = 1;

int __read_mostly watchdog_thresh = 10;

static int __read_mostly watchdog_disabled = 1;

static int __read_mostly watchdog_running;

static u64 __read_mostly sample_period;



static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
@@ -63,7 +63,7 @@ static int __init hardlockup_panic_setup(char *str) 
	else if (!strncmp(str, "nopanic", 7))

		hardlockup_panic = 0;

	else if (!strncmp(str, "0", 1))

		watchdog_enabled = 0;

		watchdog_user_enabled = 0;

	return 1;

}

__setup("nmi_watchdog=", hardlockup_panic_setup);
@@ -82,7 +82,7 @@ __setup("softlockup_panic=", softlockup_panic_setup); 


static int __init nowatchdog_setup(char *str)

{

	watchdog_enabled = 0;

	watchdog_user_enabled = 0;

	return 1;

}

__setup("nowatchdog", nowatchdog_setup);
@@ -90,7 +90,7 @@ __setup("nowatchdog", nowatchdog_setup); 
/* deprecated */

static int __init nosoftlockup_setup(char *str)

{

	watchdog_enabled = 0;

	watchdog_user_enabled = 0;

	return 1;

}

__setup("nosoftlockup", nosoftlockup_setup);
@@ -158,7 +158,7 @@ void touch_all_softlockup_watchdogs(void) 
#ifdef CONFIG_HARDLOCKUP_DETECTOR

void touch_nmi_watchdog(void)

{

	if (watchdog_enabled) {

	if (watchdog_user_enabled) {

		unsigned cpu;



		for_each_present_cpu(cpu) {
@@ -490,12 +490,12 @@ static int watchdog_enable_all_cpus(void) 
{

	int err = 0;



	if (watchdog_disabled) {

	if (!watchdog_running) {

		err = smpboot_register_percpu_thread(&watchdog_threads);

		if (err)

			pr_err("Failed to create watchdog threads, disabled\n");

		else

			watchdog_disabled = 0;

			watchdog_running = 1;

	}



	return err;
@@ -506,8 +506,8 @@ static int watchdog_enable_all_cpus(void) 
#ifdef CONFIG_SYSCTL

static void watchdog_disable_all_cpus(void)

{

	if (!watchdog_disabled) {

		watchdog_disabled = 1;

	if (watchdog_running) {

		watchdog_running = 0;

		smpboot_unregister_percpu_thread(&watchdog_threads);

	}

}
@@ -522,7 +522,7 @@ int proc_dowatchdog(struct ctl_table *table, int write, 
	int err, old_thresh, old_enabled;



	old_thresh = ACCESS_ONCE(watchdog_thresh);

	old_enabled = ACCESS_ONCE(watchdog_enabled);

	old_enabled = ACCESS_ONCE(watchdog_user_enabled);



	err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);

	if (err || !write)
@@ -531,10 +531,10 @@ int proc_dowatchdog(struct ctl_table *table, int write, 
	set_sample_period();

	/*

	 * Watchdog threads shouldn't be enabled if they are

	 * disabled. The 'watchdog_disabled' variable check in

	 * disabled. The 'watchdog_running' variable check in

	 * watchdog_*_all_cpus() function takes care of this.

	 */

	if (watchdog_enabled && watchdog_thresh)

	if (watchdog_user_enabled && watchdog_thresh)

		err = watchdog_enable_all_cpus();

	else

		watchdog_disable_all_cpus();
@@ -542,7 +542,7 @@ int proc_dowatchdog(struct ctl_table *table, int write, 
	/* Restore old values on failure */

	if (err) {

		watchdog_thresh = old_thresh;

		watchdog_enabled = old_enabled;

		watchdog_user_enabled = old_enabled;

	}



	return err;
@@ -553,6 +553,6 @@ void __init lockup_detector_init(void) 
{

	set_sample_period();



	if (watchdog_enabled)

	if (watchdog_user_enabled)

		watchdog_enable_all_cpus();

}