Messages in this thread Patch in this message | | | Date | Tue, 13 Jan 2015 15:43:46 -0500 | From | Rik van Riel <> | Subject | Re: [RFC PATCH 06/11] x86,fpu: lazily skip fpu restore with eager fpu mode, too |
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On 01/13/2015 12:11 PM, Andy Lutomirski wrote: > On Sun, Jan 11, 2015 at 1:46 PM, <riel@redhat.com> wrote:
>> diff --git a/arch/x86/include/asm/fpu-internal.h >> b/arch/x86/include/asm/fpu-internal.h index 4db8781..a5a40c7 >> 100644 --- a/arch/x86/include/asm/fpu-internal.h +++ >> b/arch/x86/include/asm/fpu-internal.h @@ -435,13 +435,9 @@ static >> inline void switch_fpu_prepare(struct task_struct *old, struct >> task_struc old->thread.fpu.last_cpu = ~0; if (preload) { >> new->thread.fpu_counter++; - if >> (!use_eager_fpu() && fpu_lazy_restore(new, cpu)) - >> /* XXX: is this safe against ptrace??? */ - >> __thread_fpu_begin(new); - else { + >> set_thread_flag(TIF_LOAD_FPU); + if >> (!fpu_lazy_restore(new, cpu)) prefetch(new->thread.fpu.state); > > Is this prefetch still worth keeping? Wouldn't prefetching the > fpu effectively require grabbing more than one cacheline anyway?
Probably not. I'll drop it, for more code simplification.
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