Re: [tip:x86/asm] sched/x86_64: Don't save flags on context switch

From: Oleg Nesterov
Date: Mon Nov 03 2014 - 16:58:46 EST


On 11/03, Oleg Nesterov wrote:
>
> On 11/03, Andy Lutomirski wrote:
> >
> > And do we ever have TF set during a context switch? I hope not.
>
> I too hope.
>
> > Also, what's with 'jmp exit_intr' at the end of retint_kernel? Why
> > isn't that 'jmp retint_kernel'?
>
> Even better, why not "jmp retint_restore_args" ?
>
> preempt_schedule_irq() checks need_resched() and returns with irqs
> disabled, not need to to recheck test_preempt_need_resched() ?

Btw, why retint_kernel() checks "interrupts on" ? It seems to me that
that "interrupts off" is not possible, no? And this will be more clear
when we remove the "exit_intr" label.

Oleg.

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