Messages in this thread | | | Date | Fri, 1 Dec 2017 14:32:56 +0100 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH RT v2] crypto: limit more FPU-enabled sections |
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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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