Re: [Syllable-kernel] Patch: Updated atomic primitives

[Kristian V. D. V. <va...@li...>]

On Saturday 16 October 2004 9:25 pm, Jake Hamby wrote:
> As discussed recently on syllable-developer (in the "LiveCD 0.5.4 Aterm
> problems" thread), the atomic primitives in Syllable badly needed
> updating for SMP safety.
>
> <snip>
>
> Amazingly, the new kernel appears to run okay on my VMware
> setup, although I don't have an SMP installation to test on, and so this
> should be considered highly experimental.

I'm afraid we seem to be on the wrong track; the patches do not fix the 
instability on SMP systems.  The symptoms are identical to the current 0.5.4 
kernel when compiled with Gcc 3.3 and -O2 optimisations E.g. random panics 
during boot.

So far the only thing which has made any difference is to compile with -O1 
instead of -O2, so it must be an over-agresive optimisation going on 
somewhere.  It just doesn't appear to be in the atomic code.

I may still accept these atomic patches as it's probably a good idea to move 
away from direct access of atomic_t types as the kernel and drivers do now, 
and I see no harm in moving to a more Linux-centric way of doing things.  It 
will make drivers easier to port at least.  But sadly it does not fix the 
immediate problem of SMP crashes.

Back to scratching our heads it seems.

-- 
Vanders
http://syllable.sourceforge.net/
http://www.liqwyd.com