From: george anzinger <george@mvista.com>
To: Keith Whitwell <keith@tungstengraphics.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: linux-2.5.18: DRM + cmpxchg issues
Date: Tue, 28 May 2002 17:59:16 -0700 [thread overview]
Message-ID: <3CF427E4.79042F@mvista.com> (raw)
In-Reply-To: <3CF33C10.1090302@tungstengraphics.com>
Keith Whitwell wrote:
>
> Adam,
>
> I expect the answer is that we need to dig out the old one.
>
> Previously I don't think the full cmpxchg semantics werere required unless the
> box is smp -- there's no case where atomic operations are required for
> hardware interaction, for example. ...
>
> Probably this changed with preempt, though, so we need one even on UP boxes...
>
I can not think of any reason to need a lock or atomic
operation because of preempt. Even the management of the
preempt on/off flags at most requires memory barriers, even
in SMP boxen. Do you have an example?
--
George Anzinger george@mvista.com
High-res-timers:
http://sourceforge.net/projects/high-res-timers/
Real time sched: http://sourceforge.net/projects/rtsched/
Preemption patch:
http://www.kernel.org/pub/linux/kernel/people/rml
next prev parent reply other threads:[~2002-05-29 0:59 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-05-28 8:13 linux-2.5.18: DRM + cmpxchg issues Keith Whitwell
2002-05-29 0:59 ` george anzinger [this message]
2002-05-29 7:23 ` Keith Whitwell
-- strict thread matches above, loose matches on Subject: below --
2002-05-26 8:32 Adam J. Richter
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