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-rw-r--r--kernel/watchdog.c19
1 files changed, 15 insertions, 4 deletions
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 60301916f62e..6e63097fa73a 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -28,7 +28,7 @@
28#include <linux/perf_event.h> 28#include <linux/perf_event.h>
29 29
30int watchdog_enabled = 1; 30int watchdog_enabled = 1;
31int __read_mostly watchdog_thresh = 60; 31int __read_mostly watchdog_thresh = 10;
32 32
33static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts); 33static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
34static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog); 34static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
@@ -91,6 +91,17 @@ static int __init nosoftlockup_setup(char *str)
91__setup("nosoftlockup", nosoftlockup_setup); 91__setup("nosoftlockup", nosoftlockup_setup);
92/* */ 92/* */
93 93
94/*
95 * Hard-lockup warnings should be triggered after just a few seconds. Soft-
96 * lockups can have false positives under extreme conditions. So we generally
97 * want a higher threshold for soft lockups than for hard lockups. So we couple
98 * the thresholds with a factor: we make the soft threshold twice the amount of
99 * time the hard threshold is.
100 */
101static int get_softlockup_thresh()
102{
103 return watchdog_thresh * 2;
104}
94 105
95/* 106/*
96 * Returns seconds, approximately. We don't need nanosecond 107 * Returns seconds, approximately. We don't need nanosecond
@@ -110,7 +121,7 @@ static unsigned long get_sample_period(void)
110 * increment before the hardlockup detector generates 121 * increment before the hardlockup detector generates
111 * a warning 122 * a warning
112 */ 123 */
113 return watchdog_thresh * (NSEC_PER_SEC / 5); 124 return get_softlockup_thresh() * (NSEC_PER_SEC / 5);
114} 125}
115 126
116/* Commands for resetting the watchdog */ 127/* Commands for resetting the watchdog */
@@ -182,7 +193,7 @@ static int is_softlockup(unsigned long touch_ts)
182 unsigned long now = get_timestamp(smp_processor_id()); 193 unsigned long now = get_timestamp(smp_processor_id());
183 194
184 /* Warn about unreasonable delays: */ 195 /* Warn about unreasonable delays: */
185 if (time_after(now, touch_ts + watchdog_thresh)) 196 if (time_after(now, touch_ts + get_softlockup_thresh()))
186 return now - touch_ts; 197 return now - touch_ts;
187 198
188 return 0; 199 return 0;
@@ -359,7 +370,7 @@ static int watchdog_nmi_enable(int cpu)
359 370
360 /* Try to register using hardware perf events */ 371 /* Try to register using hardware perf events */
361 wd_attr = &wd_hw_attr; 372 wd_attr = &wd_hw_attr;
362 wd_attr->sample_period = hw_nmi_get_sample_period(); 373 wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh);
363 event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback); 374 event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback);
364 if (!IS_ERR(event)) { 375 if (!IS_ERR(event)) {
365 printk(KERN_INFO "NMI watchdog enabled, takes one hw-pmu counter.\n"); 376 printk(KERN_INFO "NMI watchdog enabled, takes one hw-pmu counter.\n");