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Message-ID: <29495f1d05062709041af9f9cd@mail.gmail.com>
Date: Mon, 27 Jun 2005 09:04:27 -0700
From: Nish Aravamudan <nish.aravamudan@gmail.com>
Reply-To: Nish Aravamudan <nish.aravamudan@gmail.com>
To: Denis Vlasenko <vda@ilport.com.ua>
Subject: Re: [RFC] Driver writer's guide to sleeping
Cc: linux-kernel@vger.kernel.org
In-Reply-To: <200506251250.18133.vda@ilport.com.ua>
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References: <200506251250.18133.vda@ilport.com.ua>
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On 6/25/05, Denis Vlasenko <vda@ilport.com.ua> wrote:
> Hi folks,
> 
> I'm working on a Linux wireless driver.
> 
> I compiled a little guide for myself about waiting primitives.
> I would appreciate if you look thru it. Maybe I'm wrong somewhere.

<snip>
> schedule_timeout(timeout)
<snip>
> msleep(ms)
<snip>
> msleep_interruptible(ms)
<snip>

So, there are four cases in the schedule_timeout() family of sleeps,
based one what you would like to be woken up on:

Signals and Waitqueue events:
     set_current_state(TASK_INTERRUPTIBLE);
     schedule_timeout(some_time_in_jiffies);

Signals only:
     msleep_interruptible(some_time_in_msecs);

Waitqueue events only:
      set_current_state(TASK_UNINTERRUPTIBLE);
      schedule_timeout(some_time_in_jiffies);

Neither signals nor waitqueues:
      msleep(some_time_in_msecs);

Hopefully that clears some things up.

w.r.t to wait-queue event sleeping, you probably should also be aware
of the wait_event() family of macros.

Thanks,
Nish