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