Re: [RFC/PATCH] FUSYN Realtime & robust mutexes for Linux, v2.3.1

[Linh Dang]

Rusty Russell <rusty@xxxxxxxxxxxxxxx> wrote:

> I don't think this is neccessarily true: I think that platforms with
> 64-bit compare-and-exchange can do the whole thing in userspace.
> They would set the mutex and stamp in the thread ID simultanously,
> allowing for "dead thread" detection (ie. I didn't get the lock, and
> it's a robust mutex: check the holder is still alive).

Or for priority-inheritance: try get the lock, if failed raised the
holder's priority to mine if necessary.

>
> W/o 64-bit compare-and-exchange a 100% robust solution may not be
> possible though.

PPC arch can do a lot of things in a pseudo-atomic way.

>
> Thoughts?
> Rusty.

-- 
Linh Dang
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