Re: 2.6.11-rc3-mm1: softlockup and suspend/resume

[Ingo Molnar <mingo@elte.hu>]

* Rafael J. Wysocki <rjw@sisk.pl> wrote:

> It looks like softlockup is not happy with suspend/resume:

Does it happen while writing out state to disk? I've attached a patch
for touch_softlockup_watchdog() below - but i think what we really need
is another mechanism. I'm wondering what the primary reason for the
lockup-detection is - did swsuspend stop the the softlockup threads?

	Ingo

--- linux/kernel/softlockup.c.orig
+++ linux/kernel/softlockup.c
@@ -20,6 +20,11 @@ static DEFINE_PER_CPU(unsigned long, tim
 static DEFINE_PER_CPU(unsigned long, print_timestamp) = 0;
 static DEFINE_PER_CPU(struct task_struct *, watchdog_task);
 
+void touch_softlockup_watchdog(void)
+{
+	per_cpu(timestamp, _smp_processor_id()) = jiffies;
+}
+
 /*
  * This callback runs from the timer interrupt, and checks
  * whether the watchdog thread has hung or not:
@@ -66,7 +71,7 @@ static int watchdog(void * __bind_cpu)
 	while (!kthread_should_stop()) {
 		set_current_state(TASK_INTERRUPTIBLE);
 		msleep_interruptible(HZ);
-		per_cpu(timestamp, this_cpu) = jiffies;
+		touch_softlockup_watchdog();
 	}
 	__set_current_state(TASK_RUNNING);
 
--- linux/include/linux/sched.h.orig
+++ linux/include/linux/sched.h
@@ -179,6 +179,7 @@ extern unsigned long cache_decay_ticks;
 #ifdef CONFIG_DETECT_SOFTLOCKUP
 extern void softlockup_tick(struct pt_regs *regs);
 extern void spawn_softlockup_task(void);
+extern void touch_softlockup_watchdog(void);
 #else
 static inline void softlockup_tick(struct pt_regs *regs)
 {
@@ -186,6 +187,9 @@ static inline void softlockup_tick(struc
 static inline void spawn_softlockup_task(void)
 {
 }
+static inline void touch_softlockup_watchdog(void)
+{
+}
 #endif