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Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull timer updates from Thomas Gleixner:
 - watchdog fixes for full dynticks
 - improved debug output for full dynticks
 - remove an obsolete full dynticks check
 - two ARM SoC clocksource drivers for sharing across SoCs
 - tick broadcast fix for CPU hotplug

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tick: broadcast: Check broadcast mode on CPU hotplug
  clocksource: arm_global_timer: Add ARM global timer support
  clocksource: Add Marvell Orion SoC timer
  nohz: Remove obsolete check for full dynticks CPUs to be RCU nocbs
  watchdog: Boot-disable by default on full dynticks
  watchdog: Rename confusing state variable
  watchdog: Register / unregister watchdog kthreads on sysctl control
  nohz: Warn if the machine can not perform nohz_full
This commit is contained in:
Linus Torvalds
2013-07-13 15:36:09 -07:00
parent 560ae37178 b0ec636c93
commit 0da2736686
11 changed files with 610 additions and 65 deletions
Download Patch File Download Diff File Expand all files Collapse all files
kernel/sysctl.c
+2 -2
View File
@@ -807,7 +807,7 @@ 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,
@@ -834,7 +834,7 @@ 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/time/tick-broadcast.c
+4 -1
View File
@@ -157,7 +157,10 @@ int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu)
dev->event_handler = tick_handle_periodic;
tick_device_setup_broadcast_func(dev);
cpumask_set_cpu(cpu, tick_broadcast_mask);
tick_broadcast_start_periodic(bc);
if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
tick_broadcast_start_periodic(bc);
else
tick_broadcast_setup_oneshot(bc);
ret = 1;
} else {
/*
kernel/time/tick-sched.c
+5 -10
View File
@@ -178,6 +178,11 @@ static bool can_stop_full_tick(void)
*/
if (!sched_clock_stable) {
trace_tick_stop(0, "unstable sched clock\n");
/*
* Don't allow the user to think they can get
* full NO_HZ with this machine.
*/
WARN_ONCE(1, "NO_HZ FULL will not work with unstable sched clock");
return false;
}
#endif
@@ -346,16 +351,6 @@ void __init tick_nohz_init(void)
}
cpu_notifier(tick_nohz_cpu_down_callback, 0);
/* Make sure full dynticks CPU are also RCU nocbs */
for_each_cpu(cpu, nohz_full_mask) {
if (!rcu_is_nocb_cpu(cpu)) {
pr_warning("NO_HZ: CPU %d is not RCU nocb: "
"cleared from nohz_full range", cpu);
cpumask_clear_cpu(cpu, nohz_full_mask);
}
}
cpulist_scnprintf(nohz_full_buf, sizeof(nohz_full_buf), nohz_full_mask);
pr_info("NO_HZ: Full dynticks CPUs: %s.\n", nohz_full_buf);
}
kernel/watchdog.c
+66 -51
View File
@@ -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;
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) {
@@ -347,11 +347,6 @@ static void watchdog_enable(unsigned int cpu)
hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
hrtimer->function = watchdog_timer_fn;
if (!watchdog_enabled) {
kthread_park(current);
return;
}
/* Enable the perf event */
watchdog_nmi_enable(cpu);
@@ -374,6 +369,11 @@ static void watchdog_disable(unsigned int cpu)
watchdog_nmi_disable(cpu);
}
static void watchdog_cleanup(unsigned int cpu, bool online)
{
watchdog_disable(cpu);
}
static int watchdog_should_run(unsigned int cpu)
{
return __this_cpu_read(hrtimer_interrupts) !=
@@ -475,28 +475,40 @@ static int watchdog_nmi_enable(unsigned int cpu) { return 0; }
static void watchdog_nmi_disable(unsigned int cpu) { return; }
#endif /* CONFIG_HARDLOCKUP_DETECTOR */
static struct smp_hotplug_thread watchdog_threads = {
.store = &softlockup_watchdog,
.thread_should_run = watchdog_should_run,
.thread_fn = watchdog,
.thread_comm = "watchdog/%u",
.setup = watchdog_enable,
.cleanup = watchdog_cleanup,
.park = watchdog_disable,
.unpark = watchdog_enable,
};
static int watchdog_enable_all_cpus(void)
{
int err = 0;
if (!watchdog_running) {
err = smpboot_register_percpu_thread(&watchdog_threads);
if (err)
pr_err("Failed to create watchdog threads, disabled\n");
else
watchdog_running = 1;
}
return err;
}
/* prepare/enable/disable routines */
/* sysctl functions */
#ifdef CONFIG_SYSCTL
static void watchdog_enable_all_cpus(void)
{
unsigned int cpu;
if (watchdog_disabled) {
watchdog_disabled = 0;
for_each_online_cpu(cpu)
kthread_unpark(per_cpu(softlockup_watchdog, cpu));
}
}
static void watchdog_disable_all_cpus(void)
{
unsigned int cpu;
if (!watchdog_disabled) {
watchdog_disabled = 1;
for_each_online_cpu(cpu)
kthread_park(per_cpu(softlockup_watchdog, cpu));
if (watchdog_running) {
watchdog_running = 0;
smpboot_unregister_percpu_thread(&watchdog_threads);
}
}
@@ -507,45 +519,48 @@ static void watchdog_disable_all_cpus(void)
int proc_dowatchdog(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
int ret;
int err, old_thresh, old_enabled;
if (watchdog_disabled < 0)
return -ENODEV;
old_thresh = ACCESS_ONCE(watchdog_thresh);
old_enabled = ACCESS_ONCE(watchdog_user_enabled);
ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (ret || !write)
return ret;
err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (err || !write)
return err;
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)
watchdog_enable_all_cpus();
if (watchdog_user_enabled && watchdog_thresh)
err = watchdog_enable_all_cpus();
else
watchdog_disable_all_cpus();
return ret;
/* Restore old values on failure */
if (err) {
watchdog_thresh = old_thresh;
watchdog_user_enabled = old_enabled;
}
return err;
}
#endif /* CONFIG_SYSCTL */
static struct smp_hotplug_thread watchdog_threads = {
.store = &softlockup_watchdog,
.thread_should_run = watchdog_should_run,
.thread_fn = watchdog,
.thread_comm = "watchdog/%u",
.setup = watchdog_enable,
.park = watchdog_disable,
.unpark = watchdog_enable,
};
void __init lockup_detector_init(void)
{
set_sample_period();
if (smpboot_register_percpu_thread(&watchdog_threads)) {
pr_err("Failed to create watchdog threads, disabled\n");
watchdog_disabled = -ENODEV;
#ifdef CONFIG_NO_HZ_FULL
if (watchdog_user_enabled) {
watchdog_user_enabled = 0;
pr_warning("Disabled lockup detectors by default for full dynticks\n");
pr_warning("You can reactivate it with 'sysctl -w kernel.watchdog=1'\n");
}
#endif
if (watchdog_user_enabled)
watchdog_enable_all_cpus();
}