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Date: Tue, 26 Feb 2002 12:13:20 -0800 (PST)
From: Davide Libenzi <davidel@xmailserver.org>
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To: "Richard B. Johnson" <root@chaos.analogic.com>
cc: Linux kernel <linux-kernel@vger.kernel.org>
Subject: Re: schedule()
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On Tue, 26 Feb 2002, Richard B. Johnson wrote:

>
>
> 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.

What did it do yield() to you ? Doesn't it work for your case ?



- Davide


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