[LITMUS^RT] P-RES: waking up tasks before timeout

[Björn Brandenburg]

> On 16. May 2019, at 11:32, Julien Haibach <julien.haibach at yahoo.de> wrote:
> 
> currently I am working on a mode change implementation, on top of the P-RES plugin.
> In the case of a mode change, tasks sleeping may need to be woken up before their previous mode release time.
> 
> On job completion tasks are put asleep with  
> schedule_hrtimeout(&next_release, HRTIMER_MODE_ABS);
> the task state is TASK_INTERRUPTIBLE - litmus/jobs.c:147
> 
> So my question is what is the best way to wake up a sleeping task in this plugin?
> I tried to call wake_up_process() from the plugin, but this did not work out of the box.
> 

Hi Julien,

these are standard Linux interfaces, so the regular methods apply. For instance, interruptible tasks can be woken up prematurely by a signal. Thus, presumably there are APIs for waking sleeping tasks early to implement signal delivery. I’d investigate that code path (or read through the various wake-up wrappers) to find the right API to use. 

Best,
Björn

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