Messages in this thread | | | Date | Mon, 2 Feb 2015 19:34:18 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH 6/6] x86,fpu: remove redundant increments of fpu_counter |
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On 02/02, riel@redhat.com wrote: > > From: Rik van Riel <riel@redhat.com> > > fpu.preload only gets set if new->thread.fpu_counter is already > larger than 5. Incrementing it further does absolutely nothing. > Remove those lines.
I _think_ that we increment it further on purpose. Note that fpu_counter is "char", so it seems that we want no more than 256 automatic preloads.
So I am not sure about this change. At least the changelog doesn't look right.
Oleg.
> --- a/arch/x86/include/asm/fpu-internal.h > +++ b/arch/x86/include/asm/fpu-internal.h > @@ -447,7 +447,6 @@ static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct ta > > /* Don't change CR0.TS if we just switch! */ > if (fpu.preload) { > - new->thread.fpu_counter++; > __thread_set_has_fpu(new); > prefetch(new->thread.fpu.state); > } else if (!use_eager_fpu()) > @@ -456,7 +455,6 @@ static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct ta > old->thread.fpu_counter = 0; > task_disable_lazy_fpu_restore(old); > if (fpu.preload) { > - new->thread.fpu_counter++; > if (fpu_lazy_restore(new, cpu)) > fpu.preload = 0; > else > -- > 1.9.3 >
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