Subject: Re: Restartable Atomic Sequences
To: None <email@example.com>
From: Jason R Thorpe <firstname.lastname@example.org>
Date: 08/24/2002 18:11:25
On Sun, Aug 25, 2002 at 11:36:28AM +1200, Gregory McGarry wrote:
> I'm sure you're just itching to hear the story behind this one.
> Originally, I did the mips work which allowed an atomic sequence
> to be restarted on any preemption or interrupt/exception. Restarting
> on an interrupt is easy on mips, since there is only two possible
> entry points. Seems like a simple generalisation, although I
> wasn't ever able to justify it with a good practical reason. The
> closest I came was an example of profiling some short code sequence.
> Would also be useful though for atomic sequences inside the kernel.
> i386 was a little harder, but still possible. m68k convinced me to
> only restart on preemption.
I think for userland ras, we should stick with preemption.
However, on some platforms, there is a good reason to have kernel RAS
(it could be really useful on real-i386 and sparcv7/v8 on my "newlock"
branch). I think we could think about extending the current ras API
or adding a kras API at some point in the future ... but it's not a biggie
-- Jason R. Thorpe <email@example.com>