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@@ -28,7 +28,7 @@
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#include <linux/perf_event.h>
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#include <linux/perf_event.h>
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int watchdog_enabled = 1;
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int watchdog_enabled = 1;
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-int __read_mostly softlockup_thresh = 60;
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+int __read_mostly watchdog_thresh = 10;
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static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
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static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
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static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
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static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
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@@ -91,6 +91,17 @@ static int __init nosoftlockup_setup(char *str)
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__setup("nosoftlockup", nosoftlockup_setup);
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__setup("nosoftlockup", nosoftlockup_setup);
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/* */
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/* */
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+/*
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+ * Hard-lockup warnings should be triggered after just a few seconds. Soft-
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+ * lockups can have false positives under extreme conditions. So we generally
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+ * want a higher threshold for soft lockups than for hard lockups. So we couple
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+ * the thresholds with a factor: we make the soft threshold twice the amount of
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+ * time the hard threshold is.
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+ */
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+static int get_softlockup_thresh()
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+{
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+ return watchdog_thresh * 2;
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+}
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/*
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/*
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* Returns seconds, approximately. We don't need nanosecond
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* Returns seconds, approximately. We don't need nanosecond
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@@ -105,12 +116,12 @@ static unsigned long get_timestamp(int this_cpu)
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static unsigned long get_sample_period(void)
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static unsigned long get_sample_period(void)
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{
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{
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/*
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/*
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- * convert softlockup_thresh from seconds to ns
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+ * convert watchdog_thresh from seconds to ns
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* the divide by 5 is to give hrtimer 5 chances to
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* the divide by 5 is to give hrtimer 5 chances to
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* increment before the hardlockup detector generates
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* increment before the hardlockup detector generates
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* a warning
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* a warning
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*/
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*/
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- return softlockup_thresh / 5 * NSEC_PER_SEC;
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+ return get_softlockup_thresh() * (NSEC_PER_SEC / 5);
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}
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}
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/* Commands for resetting the watchdog */
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/* Commands for resetting the watchdog */
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@@ -182,7 +193,7 @@ static int is_softlockup(unsigned long touch_ts)
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unsigned long now = get_timestamp(smp_processor_id());
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unsigned long now = get_timestamp(smp_processor_id());
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/* Warn about unreasonable delays: */
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/* Warn about unreasonable delays: */
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- if (time_after(now, touch_ts + softlockup_thresh))
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+ if (time_after(now, touch_ts + get_softlockup_thresh()))
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return now - touch_ts;
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return now - touch_ts;
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return 0;
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return 0;
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@@ -359,7 +370,7 @@ static int watchdog_nmi_enable(int cpu)
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/* Try to register using hardware perf events */
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/* Try to register using hardware perf events */
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wd_attr = &wd_hw_attr;
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wd_attr = &wd_hw_attr;
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- wd_attr->sample_period = hw_nmi_get_sample_period();
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+ wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh);
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event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback);
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event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback);
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if (!IS_ERR(event)) {
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if (!IS_ERR(event)) {
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printk(KERN_INFO "NMI watchdog enabled, takes one hw-pmu counter.\n");
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printk(KERN_INFO "NMI watchdog enabled, takes one hw-pmu counter.\n");
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@@ -501,28 +512,25 @@ static void watchdog_disable_all_cpus(void)
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/* sysctl functions */
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/* sysctl functions */
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#ifdef CONFIG_SYSCTL
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#ifdef CONFIG_SYSCTL
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/*
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/*
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- * proc handler for /proc/sys/kernel/nmi_watchdog
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+ * proc handler for /proc/sys/kernel/nmi_watchdog,watchdog_thresh
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*/
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*/
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-int proc_dowatchdog_enabled(struct ctl_table *table, int write,
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- void __user *buffer, size_t *length, loff_t *ppos)
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+int proc_dowatchdog(struct ctl_table *table, int write,
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+ void __user *buffer, size_t *lenp, loff_t *ppos)
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{
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{
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- proc_dointvec(table, write, buffer, length, ppos);
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+ int ret;
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- if (write) {
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- if (watchdog_enabled)
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- watchdog_enable_all_cpus();
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- else
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- watchdog_disable_all_cpus();
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- }
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- return 0;
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-}
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+ ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
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+ if (ret || !write)
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+ goto out;
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-int proc_dowatchdog_thresh(struct ctl_table *table, int write,
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- void __user *buffer,
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- size_t *lenp, loff_t *ppos)
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-{
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- return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
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+ if (watchdog_enabled && watchdog_thresh)
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+ watchdog_enable_all_cpus();
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+ else
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+ watchdog_disable_all_cpus();
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+
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+out:
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+ return ret;
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}
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}
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#endif /* CONFIG_SYSCTL */
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#endif /* CONFIG_SYSCTL */
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