Messages in this thread Patch in this message | | | Date | Fri, 7 Mar 2008 12:18:22 -0800 | From | Andrew Morton <> | Subject | Re: [BUG 2.6.25-rc3] scheduler/hotplug: some processes are dealocked when cpu is set to offline |
| |
On Fri, 7 Mar 2008 14:02:20 +0100 "Dmitry Adamushko" <dmitry.adamushko@gmail.com> wrote:
> Hi, > > 'watchdog' is of SCHED_FIFO class. The standard load-balancer doesn't > move RT tasks between cpus anymore and there is a special mechanism in > scher_rt.c instead (I think, it's .25 material). > > So I wonder, whether __migrate_task() is still capable of properly > moving a RT task to another CPU (e.g. for the case when it's in > TASK_RUNNING state) without breaking something in the rt migration > mechanism (or whatever else) that would leave us with a runqueue in > the 'inconsistent' state... > (I've taken a quick look at the relevant code so can't confirm it yet) > > maybe it'd be faster if somebody could do a quick test now with the > following line commented out in kernel/softlockup.c :: watchdog() > > - sched_setscheduler(current, SCHED_FIFO, ¶m); >
Yup, thanks. This:
kernel/softirq.c | 2 +- kernel/softlockup.c | 2 +- kernel/stop_machine.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-)
diff -puN kernel/softlockup.c~a kernel/softlockup.c --- a/kernel/softlockup.c~a +++ a/kernel/softlockup.c @@ -211,7 +211,7 @@ static int watchdog(void *__bind_cpu) struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; int this_cpu = (long)__bind_cpu; - sched_setscheduler(current, SCHED_FIFO, ¶m); +// sched_setscheduler(current, SCHED_FIFO, ¶m); /* initialize timestamp */ touch_softlockup_watchdog(); diff -puN kernel/stop_machine.c~a kernel/stop_machine.c --- a/kernel/stop_machine.c~a +++ a/kernel/stop_machine.c @@ -188,7 +188,7 @@ struct task_struct *__stop_machine_run(i struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; /* One high-prio thread per cpu. We'll do this one. */ - sched_setscheduler(p, SCHED_FIFO, ¶m); +// sched_setscheduler(p, SCHED_FIFO, ¶m); kthread_bind(p, cpu); wake_up_process(p); wait_for_completion(&smdata.done); diff -puN kernel/softirq.c~a kernel/softirq.c --- a/kernel/softirq.c~a +++ a/kernel/softirq.c @@ -622,7 +622,7 @@ static int __cpuinit cpu_callback(struct p = per_cpu(ksoftirqd, hotcpu); per_cpu(ksoftirqd, hotcpu) = NULL; - sched_setscheduler(p, SCHED_FIFO, ¶m); +// sched_setscheduler(p, SCHED_FIFO, ¶m); kthread_stop(p); takeover_tasklets(hotcpu); break; _ fixes the wont-power-off regression.
But 2.6.24 runs the watchdog threads SCHED_FIFO too. Are you saying that it's the migration code which changed?
| |