Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [RFC][PATCH 2/2] time: alarmtimer: Use TASK_FREEZABLE to cleanup freezer handling | Date | Mon, 20 Feb 2023 18:48:22 +0100 |
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Michael!
On Mon, Feb 20 2023 at 12:47, Michael Nazzareno Trimarchi wrote: > On Mon, Feb 20, 2023 at 9:23 AM Michael Nazzareno Trimarchi > <michael@amarulasolutions.com> wrote: >> On Mon, Feb 20, 2023 at 8:23 AM Thomas Gleixner <tglx@linutronix.de> wrote: >> > > 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.
Let me try to decode the above.
Yes, periodic timers are re-armed when the signal is delivered, but that happens way later after the system resumed.
Here is what I observe:
[ 27.349352] alarmtimer_enqueue()
U: Before SUSPEND
[ 31.353228] PM: suspend entry (s2idle) [ 31.388857] Filesystems sync: 0.033 seconds [ 31.418427] Freezing user space processes [ 31.422406] Freezing user space processes completed (elapsed 0.002 seconds) [ 31.425435] OOM killer disabled. [ 31.426833] Freezing remaining freezable tasks [ 31.429838] Freezing remaining freezable tasks completed (elapsed 0.001 seconds) [ 31.432922] printk: Suspending console(s) (use no_console_suspend to debug) [ 31.435912] alarmtimer alarmtimer.0.auto: PM: dpm_run_callback(): platform_pm_suspend+0x0/0x50 returns -16 [ 31.435954] alarmtimer alarmtimer.0.auto: PM: failed to suspend: error -16
That means the RTC interrupt was raised before the system was able to suspend.
[ 31.436077] PM: Some devices failed to suspend, or early wake event detected [ 31.444270] OOM killer enabled. [ 31.445011] Restarting tasks ... done. [ 31.446820] random: crng reseeded on system resumption [ 31.466019] PM: suspend exit
[ 31.480283] alarmtimer_fired() [ 31.481403] alarmtimer_dequeue() <- Signal queued
[ 31.482596] alarmtimer_rearm()_ <- Signal delivery [ 31.483713] alarmtimer_enqueue()
U: ALRM signal received <- User space signal handler U: Post Suspend <- system("echo .... >") returns
That's 6.2 + John's patches.
Thanks,
tglx
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