Re: [patch] sched: unlocked context-switches

[Benjamin Herrenschmidt]

On Sat, 2005-04-09 at 06:38 +0200, Ingo Molnar wrote:
> * Luck, Tony <tony.luck@xxxxxxxxx> wrote:
> 
> > >tested on x86, and all other arches should work as well, but if an 
> > >architecture has irqs-off assumptions in its switch_to() logic 
> > >it might break. (I havent found any but there may such assumptions.)
> > 
> > The ia64_switch_to() code includes a section that can change a pinned
> > MMU mapping (when the stack for the new process is in a different
> > granule from the stack for the old process).  [...]
> 
> thanks - updated patch below. Any other architectures that switch the 
> kernel stack in a nonatomic way? x86/x64 switches it atomically.

ppc64 already has a local_irq_save/restore in switch_to, around the low
level asm bits, so it should be fine.

Ben.


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