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Subject: Re: [2.4.17/18pre] VM and swap - it's really unusable
From: Robert Love <rml@tech9.net>
To: John Alvord <jalvo@mbay.net>
Cc: linux-kernel@vger.kernel.org
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Date: 08 Jan 2002 19:43:25 -0500
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On Tue, 2002-01-08 at 19:29, John Alvord wrote:

> The best part about planned preemption points is that there is minimal
> state to save when an interruption occurs.

Actually, both preempt-kernel and low-latency do about the same amount
of work re saving state.

With preempt-kernel, when a task is preempted in-kernel we AND a flag
value into the preempt count.  That is all we need to keep track of
things.

With low-latency, the task state is set to TASK_RUNNING (which is a
precautionary measure).  So it is about the same, although low-latency
(and lock-break) often also have to do various setup with the locks and
all.

	Robert Love

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