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Subject: Re: [2.4.17/18pre] VM and swap - it's really unusable
From: Robert Love <rml@tech9.net>
To: Roman Zippel <zippel@linux-m68k.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>, Kenneth Johansson <ken@canit.se>,
        arjan@fenrus.demon.nl, Rob Landley <landley@trommello.org>,
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Date: 13 Jan 2002 13:13:46 -0500
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On Sun, 2002-01-13 at 10:18, Roman Zippel wrote:

> What somehow got lost in this discussion, that both patches don't
> necessarily conflict with each other, they both attack the same problem
> with different approaches, which complement each other. I prefer to get
> the best of both patches.
> The ll patch identifies problem, which preempt alone can't fix, on the
> other hand the ll patch inserts schedule calls all over the place, where
> preempt can handle this transparently. So far I haven't seen any
> evidence, that preempt introduces any _new_ serious problems, so I'd
> rather like to see to get the best out of both.

Good point.  In fact, I have an "ll patch" for preempt-kernel, it is
called lock-break and available at
	ftp://ftp.kernel.org/pub/linux/kernel/people/rml/lock-break

While I am not so sure this sort of explicit work is the answer -- I'd
much prefer to work on the algorithms to shorten lock time or lock into
different locks -- it does work.  The work is based heavily on Andrew's
ll patch but designed for use with preempt-kernel.  This means we can
drop some of the conditional schedules that aren't needed, and in others
we don't need to call schedule (just drop the locks).

	Robert Love

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