Re: [PATCH RFC 4/5] x86,fpu: lazily skip FPU restore when still loaded
From: Rik van Riel
Date: Mon Oct 03 2016 - 17:03:28 EST
On Mon, 2016-10-03 at 13:49 -0700, Dave Hansen wrote:
> On 10/03/2016 01:22 PM, Rik van Riel wrote:
> > >
> > > >
> > > > What are the preempt rules with this thing?ÂÂThis needs to be
> > > > called
> > > > in preempt-disabled contexts, right?
> > Indeed, all the FPU context switching code needsÂ
> > 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.ÂÂCould you just add a comment about
> to make it clear that it's also the case for this new
> fpu_lazy_skip_restore() helper?
Turns out the code already has an old
fpu_want_lazy_restore(), which is what
I will use instead :)
I will add documentation about preemption
in places where it is necessary.
All rights reversed
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