Messages in this thread Patch in this message | | | Date | Sat, 2 Feb 2008 00:25:50 +0100 | From | Ingo Molnar <> | Subject | Re: [Regression] 2.6.24-git3: Major annoyance during suspend/hibernation on x86-64 (bisected) |
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* Dmitry Adamushko <dmitry.adamushko@gmail.com> wrote:
> yeah, I was already on a half-way to check it out. > > It does fix a problem for me. > > Don't forget to take along these 2 fixes from Peter's patch: > > - fix break usage in do_each_thread() { } while_each_thread(). > - fix the hotplug switch stmt, a fall-through case was broken.
Dmitry, i sent Peter's fix(es) below to Linus. Do you concur that it fixes all the practical and theoretical problems you could see with the code too?
Ingo
---------------> Subject: debug: softlockup looping fix From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Rafael J. Wysocki reported weird, multi-seconds delays during suspend/resume and bisected it back to:
commit 82a1fcb90287052aabfa235e7ffc693ea003fe69 Author: Ingo Molnar <mingo@elte.hu> Date: Fri Jan 25 21:08:02 2008 +0100
softlockup: automatically detect hung TASK_UNINTERRUPTIBLE tasks
fix it:
- restore the old wakeup mechanism - fix break usage in do_each_thread() { } while_each_thread(). - fix the hotplug switch stmt, a fall-through case was broken.
Bisected-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Ingo Molnar <mingo@elte.hu> --- kernel/softlockup.c | 30 ++++++++++++++++++++---------- 1 file changed, 20 insertions(+), 10 deletions(-)
Index: linux/kernel/softlockup.c =================================================================== --- linux.orig/kernel/softlockup.c +++ linux/kernel/softlockup.c @@ -101,6 +101,10 @@ void softlockup_tick(void) now = get_timestamp(this_cpu); + /* Wake up the high-prio watchdog task every second: */ + if (now > (touch_timestamp + 1)) + wake_up_process(per_cpu(watchdog_task, this_cpu)); + /* Warn about unreasonable delays: */ if (now <= (touch_timestamp + softlockup_thresh)) return; @@ -191,11 +195,11 @@ static void check_hung_uninterruptible_t read_lock(&tasklist_lock); do_each_thread(g, t) { if (!--max_count) - break; + goto unlock; if (t->state & TASK_UNINTERRUPTIBLE) check_hung_task(t, now); } while_each_thread(g, t); - + unlock: read_unlock(&tasklist_lock); } @@ -218,14 +222,19 @@ static int watchdog(void *__bind_cpu) * debug-printout triggers in softlockup_tick(). */ while (!kthread_should_stop()) { + set_current_state(TASK_INTERRUPTIBLE); touch_softlockup_watchdog(); - msleep_interruptible(10000); + schedule(); + + if (kthread_should_stop()) + break; if (this_cpu != check_cpu) continue; if (sysctl_hung_task_timeout_secs) check_hung_uninterruptible_tasks(this_cpu); + } return 0; @@ -259,13 +268,6 @@ cpu_callback(struct notifier_block *nfb, wake_up_process(per_cpu(watchdog_task, hotcpu)); break; #ifdef CONFIG_HOTPLUG_CPU - case CPU_UP_CANCELED: - case CPU_UP_CANCELED_FROZEN: - if (!per_cpu(watchdog_task, hotcpu)) - break; - /* Unbind so it can run. Fall thru. */ - kthread_bind(per_cpu(watchdog_task, hotcpu), - any_online_cpu(cpu_online_map)); case CPU_DOWN_PREPARE: case CPU_DOWN_PREPARE_FROZEN: if (hotcpu == check_cpu) { @@ -275,6 +277,14 @@ cpu_callback(struct notifier_block *nfb, check_cpu = any_online_cpu(temp_cpu_online_map); } break; + + case CPU_UP_CANCELED: + case CPU_UP_CANCELED_FROZEN: + if (!per_cpu(watchdog_task, hotcpu)) + break; + /* Unbind so it can run. Fall thru. */ + kthread_bind(per_cpu(watchdog_task, hotcpu), + any_online_cpu(cpu_online_map)); case CPU_DEAD: case CPU_DEAD_FROZEN: p = per_cpu(watchdog_task, hotcpu);
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