From: "Manfred Spraul" <manfred@colorfullife.com>
To: "Roger Larsson" <roger.larsson@norran.net>
Cc: <linux-kernel@vger.kernel.org>, "Robert Love" <rml@tech9.net>,
<nigel@nrg.org>
Subject: Re: [SMP lock BUG?] Re: Feedback on preemptible kernel patch
Date: Sun, 9 Sep 2001 01:11:05 +0200 [thread overview]
Message-ID: <000901c138bb$8e151270$010411ac@local> (raw)
> This is interesting. [Assumes UP Athlon - correct]
> Note that all BUGs out in highmem.h:95 (kmap_atomic)
> and that test is only on if you have enabled HIGHMEM_DEBUG
> [my analyze is done with a 2.4.10-pre2 kernel, but I checked with
> later patches and I do not think they fix it either...]
>
> The preemptive kernel puts more SMP stress on the kernel than
> running with multiple CPUs.
>
> So this might be a potential bug in the kernel proper, running with
> a SMP computer.
No.
It seems to be a missing ctx_sw_off() in highmem.h:
kmap_atomic uses a per-cpu variable, thus ctx_sw_off() is needed in
kmap_atomic, and ctx_sw_on() in kunmap_atomic().
--
Manfred
next reply other threads:[~2001-09-08 23:11 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-09-08 23:11 Manfred Spraul [this message]
2001-09-09 3:44 ` [SMP lock BUG?] Re: Feedback on preemptible kernel patch Robert Love
2001-09-09 7:38 ` Manfred Spraul
[not found] ` <001a01c1390262c7f30/mnt/sendme10411ac@local>
2001-09-14 9:15 ` Pavel Machek
2001-09-17 22:40 ` Manfred Spraul
2001-09-18 0:19 ` Robert Love
2001-09-17 22:41 ` Robert Love
-- strict thread matches above, loose matches on Subject: below --
2001-09-08 17:33 Arjan Filius
2001-09-08 20:58 ` [SMP lock BUG?] " Roger Larsson
2001-09-08 20:58 ` Roger Larsson
2001-09-08 22:18 ` Arjan Filius
2001-09-08 22:18 ` Arjan Filius
2001-09-09 14:55 ` george anzinger
2001-09-09 14:55 ` george anzinger
2001-09-09 22:25 ` Arjan Filius
2001-09-09 22:25 ` Arjan Filius
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