From: David Woodhouse <dwmw2@infradead.org>
To: Chris Wedgwood <cw@f00f.org>
Cc: Rik van Riel <riel@conectiva.com.br>,
Peter Rival <frival@zk3.dec.com>,
Anton Blanchard <anton@samba.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] CPU hot swap for 2.4.3 + s390 support
Date: Sun, 06 May 2001 16:38:18 +0100 [thread overview]
Message-ID: <12862.989163498@redhat.com> (raw)
In-Reply-To: <20010506142548.D31269@metastasis.f00f.org>
In-Reply-To: <20010506142548.D31269@metastasis.f00f.org> <20010506033746.A30690@metastasis.f00f.org> <Pine.LNX.4.21.0105052317080.582-100000@imladris.rielhome.conectiva>
cw@f00f.org said:
> How do you relocate
> -- pages which are mlocked without violating RT contraints?
> -- pages which contain kernel pointers and might be accessed from
> interrupt context?
Those two are the same problem, essentially. You have to copy the page,
then map it into the same virtual address (be that userspace or
kernelspace) as the old one. Mark the page readonly when you start to copy
it, and have a fault handler which immediately marks it writable and
returns. If the source is writable by the time you've finished the copy,
repeat.
If you have to repeat yourself more than $n times, you're probably
experiencing livelock. At that point, do what Rik said - to hell with the
RT constraints, disable interrupts and do the copy. At least your cache is
warm :)
--
dwmw2
next prev parent reply other threads:[~2001-05-06 15:45 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-05-05 13:37 [PATCH] CPU hot swap for 2.4.3 + s390 support Anton Blanchard
2001-05-05 14:43 ` Peter Rival
2001-05-05 15:37 ` Chris Wedgwood
2001-05-05 16:34 ` Mitch Adair
2001-05-06 1:53 ` Chris Wedgwood
2001-05-06 2:24 ` Rik van Riel
2001-05-06 2:19 ` Rik van Riel
2001-05-06 0:08 ` Peter Rival
2001-05-06 2:02 ` Chris Wedgwood
2001-05-06 2:19 ` Rik van Riel
2001-05-06 2:25 ` Chris Wedgwood
2001-05-06 2:31 ` Rik van Riel
2001-05-06 15:38 ` David Woodhouse [this message]
2001-05-06 8:03 ` Aaron Lehmann
2001-05-06 8:43 ` Stephen Beynon
2001-05-06 7:15 ` Dwayne C. Litzenberger
2001-05-06 8:04 ` Aaron Lehmann
2001-05-06 17:06 ` Ben Ford
2001-05-07 1:42 ` Jakob Østergaard
2001-05-05 20:49 ` Bruce Harada
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