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

From	Rik van Riel <riel@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH RFC 4/5] x86,fpu: lazily skip FPU restore when still loaded
Date	2016-10-03 23:10 +0200
Message-ID	<soiEO-1DF-25@gated-at.bofh.it> (permalink)
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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?  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?

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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[PATCH RFC 4/5] x86,fpu: lazily skip FPU restore when still loaded riel@redhat.com - 2016-10-01 23:00 +0200
  Re: [PATCH RFC 4/5] x86,fpu: lazily skip FPU restore when still  loaded Dave Hansen <dave.hansen@linux.intel.com> - 2016-10-03 22:10 +0200
    Re: [PATCH RFC 4/5] x86,fpu: lazily skip FPU restore when still  loaded Rik van Riel <riel@redhat.com> - 2016-10-03 22:30 +0200
      Re: [PATCH RFC 4/5] x86,fpu: lazily skip FPU restore when still  loaded Dave Hansen <dave.hansen@linux.intel.com> - 2016-10-03 23:00 +0200
        Re: [PATCH RFC 4/5] x86,fpu: lazily skip FPU restore when still  loaded Rik van Riel <riel@redhat.com> - 2016-10-03 23:10 +0200

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