Re: [PATCH] powerpc/8xx: reduce pressure on TLB due to context switches

Scott Wood
2015-01-07T02:53:30Z

On Mon, 2015-01-05 at 16:14 +0100, Christophe Leroy wrote:
> + }
> + __clear_bit(id, stale_map[cpu]);
> +
> + }

Whitespace

> +
> + /* Flush the TLB for all contexts */
> + _tlbil_all();

Can you put a comment in here pointing out that for this to work on SMP,
it needs to be a global invalidation, or at least some indication on
this function that it's not SMP-safe? I realize there's no SMP 8xx, and
this is only called in place of steal_context_up(), but in case others
think of reusing this elsewhere[1]...

-Scott

[1] It might be helpful on e500 derivatives in virtualized environments
where invalidate-by-PID is expensive, depending on how often stealing
happens there.