Messages in this thread | | | From | Michael Nazzareno Trimarchi <> | Date | Mon, 20 Feb 2023 09:23:04 +0100 | Subject | Re: [RFC][PATCH 2/2] time: alarmtimer: Use TASK_FREEZABLE to cleanup freezer handling |
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Hi Thomas
On Mon, Feb 20, 2023 at 8:23 AM Thomas Gleixner <tglx@linutronix.de> wrote: > > On Sat, Feb 18 2023 at 15:56, Michael Nazzareno Trimarchi wrote: > > > > I have changed the alarm test to check some corner case > > Could you tell us please which test did you change and what the change is? >
if (timer_create(CLOCK_REALTIME_ALARM, &se, &tm1) == -1) { printf("timer_create failed, %s unsupported?\n", clockstring(alarm_clock_id)); exit(1); }
clock_gettime(alarm_clock_id, &start_time); printf("Start time (%s): %ld:%ld\n", clockstring(alarm_clock_id), start_time.tv_sec, start_time.tv_nsec); printf("Setting alarm for every %i seconds\n", SUSPEND_SECS); its1.it_value = start_time; its1.it_value.tv_sec += 4; /* Empiric value for get in between a freeze task and fire of the timer */ its1.it_value.tv_nsec += 132079666; its1.it_interval.tv_sec = 4; its1.it_interval.tv_nsec = 0;
timer_settime(tm1, TIMER_ABSTIME, &its1, &its2);
printf("Starting suspend loops\n"); while (1) { int ret; sleep(4); system("echo mem > /sys/power/state"); }
> > periodic_alarm > > Start time (CLOCK_REALTIME_ALARM)[ 85.624819] alarmtimer_enqueue: called > > : 94:865096467 > > Setting alarm for every 4 seconds > > Starting suspend loops > > [ 89.674127] PM: suspend entry (deep) > > [ 89.714916] Filesystems sync: 0.037 seconds > > [ 89.733594] Freezing user space processes > > [ 89.740680] Freezing user space processes completed (elapsed 0.002 seconds) > > [ 89.748593] OOM killer disabled. > > [ 89.752257] Freezing remaining freezable tasks > > [ 89.756807] alarmtimer_fired: called > > [ 89.756831] alarmtimer_dequeue: called <---- HERE > > > > I have the dequeue but not an enquee of the periodic alarm. I was > > thinking that create a periodic time of 4 seconds > > and have the first alarm on suspend will always guarantee the re-arm > > it but it's not working as I expect > > Again. You are not telling what you expect. It depends on how the timer > is set up whether the timer is self rearmed or not. >
Posted the pseudo code. As far as I understand, the timer periodic is re-armed in get_signal do_work_pending->do_signal()->get_signal(), then in the posix timer code the enqueue_alarm is called. All the timers used from suspend are coming from the expiration list that contains only the enqueue alarm
My test case is a single core, arm and with only one REAL_TIME_ALARM periodic timer created.
Michael
> Thanks, > > tglx
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