linux-kernel - Re: [RFC][PATCH 2/2] time: alarmtimer: Use TASK

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Message-ID: <87o7porea9.ffs@tglx>
Date:   Mon, 20 Feb 2023 08:23:26 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Michael Nazzareno Trimarchi <michael@...rulasolutions.com>,
        John Stultz <jstultz@...gle.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Stephen Boyd <sboyd@...nel.org>, Arnd Bergmann <arnd@...db.de>,
        Michael <michael@...isi.de>, kernel-team@...roid.com
Subject: Re: [RFC][PATCH 2/2] time: alarmtimer: Use TASK_FREEZABLE to
 cleanup freezer handling

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?

> 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.

Thanks,

        tglx