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Date: Tue, 26 Feb 2002 14:57:10 -0500 (EST)
From: "Richard B. Johnson" <root@chaos.analogic.com>
Reply-To: root@chaos.analogic.com
To: Linux kernel <linux-kernel@vger.kernel.org>
Subject: schedule()
Message-ID: <Pine.LNX.3.95.1020226145622.5179A-100000@chaos.analogic.com>
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I just read on this list that:

    while(something)
    {
      current->policy |= SCHED_YIELD;
      schedule();
    }

Will no longer be allowed in a kernel module! If this is true, how
do I loop, waiting for a bit in a port, without wasting CPU time?

A lot of hardware does not generate interrupts upon a condition,
there is no CPU activity that could send a wake_up_interruptible()
to something sleeping.

For instance, I need to write data to a hardware FIFO, one long-word
at a time, but I can't just write. I have to wait for a bit to be
set or reset for each and every write. I'm going to be burning a
lot of CPU cycles if I can't schedule() while the trickle-down-effect
of the hardware is happening.


Cheers,
Dick Johnson

Penguin : Linux version 2.4.1 on an i686 machine (797.90 BogoMips).

        111,111,111 * 111,111,111 = 12,345,678,987,654,321

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