On 2017-12-01 12:32:35 [+0100], Peter Zijlstra wrote:
> On Fri, Dec 01, 2017 at 11:44:22AM +0100, Sebastian Andrzej Siewior wrote:
…
> > +static void camellia_fpu_sched_rt(struct crypt_priv *ctx)
> > +{
> > + bool fpu_enabled = ctx->fpu_enabled;
> > +
> > + if (!fpu_enabled || !tif_need_resched_now())
> > + return;
> > + camellia_fpu_end(fpu_enabled);
> > + kernel_fpu_end();
> > + /* schedule due to preemptible */
> > + kernel_fpu_begin();
> > +}
>
> There's a ton of duplication in there; you're not nearly lazy enough.
>
> Why can't we do something simple like kernel_fpu_resched() ?
>
> diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
> index f92a6593de1e..05321b98a55a 100644
> --- a/arch/x86/kernel/fpu/core.c
> +++ b/arch/x86/kernel/fpu/core.c
> @@ -130,6 +130,18 @@ void kernel_fpu_begin(void)
> }
> EXPORT_SYMBOL_GPL(kernel_fpu_begin);
>
> +void kernel_fpu_resched(void)
> +{
> + WARN_ON_FPU(!this_cpu_read(in_kernel_fpu));
> +
> + if (should_resched(PREEMPT_OFFSET)) {
> + kernel_fpu_end();
> + cond_resched();
> + kernel_fpu_begin();
I can do that but I would still keep it RT only to avoid the
kernel_fpu_begin/end to be invoked more often on !RT.
But why that cond_resched()? kernel_fpu_end() ends with preempt_enable()
and this one should do the trick.
> + }
> +}
> +EXPORT_SYMBOL_GPL(kernel_fpu_resched);
> +
> void kernel_fpu_end(void)
> {
> __kernel_fpu_end();
Sebastian
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