Kernel warns of softlockups if the softlockup thread is not able to run
on a CPU for 10s. It is useful to lower the softlockup warning
threshold in testing environments to catch potential lockups early.
Following patch adds a kernel parameter 'softlockup_lim' to control
the softlockup threshold.
Thanks,
Kiran
Control the trigger limit for softlockup warnings. This is useful for
debugging softlockups, by lowering the softlockup_lim to identify
possible softlockups earlier.
Signed-off-by: Ravikiran Thirumalai <[email protected]>
Signed-off-by: Shai Fultheim <[email protected]>
Index: linux-2.6.22/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6.22.orig/Documentation/kernel-parameters.txt 2007-07-08 16:32:17.000000000 -0700
+++ linux-2.6.22/Documentation/kernel-parameters.txt 2007-07-16 14:07:34.907116001 -0700
@@ -1781,6 +1781,10 @@ and is between 256 and 4096 characters.
snd-ymfpci= [HW,ALSA]
+ softlockup_lim=
+ [KNL] Soft lock up tolerance limit in seconds
+ { 1 - 10 }
+
sonycd535= [HW,CD]
Format: <io>[,<irq>]
Index: linux-2.6.22/kernel/softlockup.c
===================================================================
--- linux-2.6.22.orig/kernel/softlockup.c 2007-07-08 16:32:17.000000000 -0700
+++ linux-2.6.22/kernel/softlockup.c 2007-07-11 12:50:05.280460591 -0700
@@ -21,6 +21,7 @@ static DEFINE_PER_CPU(unsigned long, pri
static DEFINE_PER_CPU(struct task_struct *, watchdog_task);
static int did_panic = 0;
+static int softlockup_lim = 10;
static int
softlock_panic(struct notifier_block *this, unsigned long event, void *ptr)
@@ -34,6 +35,20 @@ static struct notifier_block panic_block
.notifier_call = softlock_panic,
};
+static int __init softlockup_lim_setup(char *str)
+{
+ int lim = simple_strtol(str, NULL, 0);
+ if(lim > 0 && lim <= 10) {
+ softlockup_lim = lim;
+ } else {
+ printk("%s: Invalid softlockup_lim parameter. ", __func__);
+ printk("Using defaults.\n");
+ }
+ return 1;
+}
+
+__setup("softlockup_lim=", softlockup_lim_setup);
+
/*
* Returns seconds, approximately. We don't need nanosecond
* resolution, and we don't need to waste time with a big divide when
@@ -97,7 +112,7 @@ void softlockup_tick(void)
wake_up_process(per_cpu(watchdog_task, this_cpu));
/* Warn about unreasonable 10+ seconds delays: */
- if (now > (touch_timestamp + 10)) {
+ if (now > (touch_timestamp + softlockup_lim)) {
per_cpu(print_timestamp, this_cpu) = touch_timestamp;
spin_lock(&print_lock);
-
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