Messages in this thread | | | Date | Fri, 16 Jan 2015 16:54:45 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH 2/3] x86, fpu: don't abuse ->has_fpu in __kernel_fpu_{begin,end}() |
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On 01/15, Rik van Riel wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On 01/15/2015 02:20 PM, Oleg Nesterov wrote: > > b/arch/x86/kernel/i387.c @@ -81,9 +81,7 @@ void > > __kernel_fpu_begin(void) this_cpu_write(in_kernel_fpu, true); > > > > if (__thread_has_fpu(me)) { - __thread_clear_has_fpu(me); > > I will put that line back in the patch series that defers the > loading of FPU state until the switch to user space,
I think this needs more discussion.
Firstly, __thread_clear_has_fpu() should go into __kernel_fpu_end(), it should replace restore_fpu_checking().
But does your series actually need this change? Correctness-wise this is not needed (afaics). Performance-wise I am not sure, kernel_fpu_begin() is unlikely event. Plus I am not sure this is a win (in general), but I can be easily wrong.
> but I > guess we can go either way for now...
Yes, this should not really conflict with your changes in any case.
Given that you acked 1/3 and 3/3, perhaps you can ack this one as well?
Oleg.
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