linux-kernel - Re: General question about TASK_INTERRUPTIBLE and schedule

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Date:	Wed, 31 Aug 2011 18:35:24 +0530
From:	sifram rajas <sifram.rajas@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: Re: General question about TASK_INTERRUPTIBLE and schedule_timeout()

Hi,

If this is a problem, then can this be solved by disabling preemption
in the following
manner ? :
preempt_disable() ;
set_current_state(TASK_INTERRUPTIBLE) ;
schedule_timeout(<some value>);
preempt_enable() ;



On Wed, Aug 31, 2011 at 6:18 PM, sifram rajas <sifram.rajas@...il.com> wrote:
> Hi,
>
> I have a general question about the following 2 lines of code I see
> all over the kernel:
> 1         set_current_state(TASK_INTERRUPTIBLE) ;
> 2         schedule_timeout(<some value>);
>
> In the above code, if we encounter an interrupt after executing line
> 1, we will end up
> call schedule() from the architecture specific code for CONFIG_PREEMPT
> kernels, after
> the interrupt handler has been invokled.
>
> This will cause the current task to sleep interruptibly forever
> instead of for a certain timeout interval.
>
> Won't this defeat the purpose of the above code to schedule out or
> sleep for a certain finite timeout ?
> If yes, then what are the techniques to solve this problem ?
>
>
> Thanks,
> Sifram.
>
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