Re: [PATCH RFC 4/5] x86,fpu: lazily skip FPU restore when still loaded

From: Dave Hansen
Date: Mon Oct 03 2016 - 16:50:41 EST

On 10/03/2016 01:22 PM, Rik van Riel wrote:
>> > What are the preempt rules with this thing? This needs to be called
>> > in preempt-disabled contexts, right?
> Indeed, all the FPU context switching code needs
> to be called in preempt-disabled contexts.
> You do not want to get preempted halfway through
> saving or restoring floating point registers.

OK, cool, that's what I expected. Could you just add a comment about it
to make it clear that it's also the case for this new
fpu_lazy_skip_restore() helper?