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Commit 11/14 of sched_lock decomposition.

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- There is no globally visible scheduler lock any longer.  For now the
   watchdog can only check Giant.  This model of checking particular locks
   is flawed and should be revisited.  Other metrics should be considered.

Tested by:      kris, current@
Tested on:      i386, amd64, ULE, 4BSD, libthr, libkse, PREEMPTION, etc.
Discussed with: kris, attilio, kmacy, jhb, julian, bde (small parts each)
This commit is contained in:
jeff 2007-06-04 23:56:33 +00:00
parent 20e0f793e8
commit b980923789
2 changed files with 0 additions and 60 deletions
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30
sys/amd64/amd64/mp_watchdog.c
View File

@ -105,9 +105,7 @@ watchdog_function(void *arg)
* locks to make sure. Then reset the timer.
*/
mtx_lock(&Giant);
mtx_lock_spin(&sched_lock);
watchdog_timer = WATCHDOG_THRESHOLD;
mtx_unlock_spin(&sched_lock);
mtx_unlock(&Giant);
callout_reset(&watchdog_callout, 1 * hz, watchdog_function, NULL);
}
@ -155,34 +153,6 @@ sysctl_watchdog(SYSCTL_HANDLER_ARGS)
SYSCTL_PROC(_debug, OID_AUTO, watchdog, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
sysctl_watchdog, "I", "");
/*
* A badly behaved sysctl that leaks the sched lock when written to. Then
* spin holding it just to make matters worse. This can be used to test the
* effectiveness of the watchdog by generating a fairly hard and nast hang.
* Note that Giant is also held in the current world order when we get here.
*/
static int
sysctl_leak_schedlock(SYSCTL_HANDLER_ARGS)
{
int error, temp;
temp = 0;
error = sysctl_handle_int(oidp, &temp, 0, req);
if (error)
return (error);
if (req->newptr != NULL) {
if (temp) {
printf("Leaking the sched lock...\n");
mtx_lock_spin(&sched_lock);
while (1);
}
}
return (0);
}
SYSCTL_PROC(_debug, OID_AUTO, leak_schedlock, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
sysctl_leak_schedlock, "IU", "");
/*
* Drop into the debugger by sending an IPI NMI to the boot processor.
*/

30
sys/i386/i386/mp_watchdog.c
View File

@ -105,9 +105,7 @@ watchdog_function(void *arg)
* locks to make sure. Then reset the timer.
*/
mtx_lock(&Giant);
mtx_lock_spin(&sched_lock);
watchdog_timer = WATCHDOG_THRESHOLD;
mtx_unlock_spin(&sched_lock);
mtx_unlock(&Giant);
callout_reset(&watchdog_callout, 1 * hz, watchdog_function, NULL);
}
@ -155,34 +153,6 @@ sysctl_watchdog(SYSCTL_HANDLER_ARGS)
SYSCTL_PROC(_debug, OID_AUTO, watchdog, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
sysctl_watchdog, "I", "");
/*
* A badly behaved sysctl that leaks the sched lock when written to. Then
* spin holding it just to make matters worse. This can be used to test the
* effectiveness of the watchdog by generating a fairly hard and nast hang.
* Note that Giant is also held in the current world order when we get here.
*/
static int
sysctl_leak_schedlock(SYSCTL_HANDLER_ARGS)
{
int error, temp;
temp = 0;
error = sysctl_handle_int(oidp, &temp, 0, req);
if (error)
return (error);
if (req->newptr != NULL) {
if (temp) {
printf("Leaking the sched lock...\n");
mtx_lock_spin(&sched_lock);
while (1);
}
}
return (0);
}
SYSCTL_PROC(_debug, OID_AUTO, leak_schedlock, CTLTYPE_INT|CTLFLAG_RW, 0, 0,
sysctl_leak_schedlock, "IU", "");
/*
* Drop into the debugger by sending an IPI NMI to the boot processor.
*/