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From: "Richard B. Johnson" <root@chaos.analogic.com>
To: Linux kernel <linux-kernel@vger.kernel.org>
Subject: timing code in 2.6.1
Date: Fri, 16 Jan 2004 11:51:52 -0500 (EST)	[thread overview]
Message-ID: <Pine.LNX.4.53.0401161150390.28039@chaos> (raw)


Some drivers are being re-written for 2.6++. The following
construct seems to work for "waiting for an event" in
the kernel modules.

        // No locks are being held
        tim = jiffies + EVENT_TIMEOUT;
        while(!event() && time_before(jiffies, tim))
            schedule_timeout(0);

Is there anything wrong?
Do I have to execute "set_current_state(TASK_INTERRUPTIBLE)" before?
Do I have to execute "set_current_state(TASK_RUNNING)" after?

I don't want to have to change this again so I really need to
know. For instance, if I execute "set_current_state(TASK_INTERRUPTIBLE)"
in version 2.4.24, it didn't hurt anything. In 2.6.1, there are
conditions where schedule_timeout(0) doesn't return if another
task is spinning "while(1) ; ". This is NotGood(tm).

Cheers,
Dick Johnson
Penguin : Linux version 2.4.24 on an i686 machine (797.90 BogoMips).
            Note 96.31% of all statistics are fiction.



             reply	other threads:[~2004-01-16 16:49 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-01-16 16:51 Richard B. Johnson [this message]
2004-01-16 23:31 ` Andrew Morton
2004-01-19 14:11   ` Richard B. Johnson
2004-01-20  9:59     ` George Anzinger
2004-01-22  2:26     ` Jamie Lokier

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