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

[Oleg Nesterov]

Didn't notice this part yesterday...

On 11/03, Andy Lutomirski wrote:
>
> On Mon, Nov 3, 2014 at 1:58 PM, Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
> > On 11/03, Oleg Nesterov wrote:
> >>
> >> On 11/03, Andy Lutomirski wrote:
> >> >
> >> > 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() ?
>
> Seems reasonable to me.  Want to write the patch?

OK, will try to do tomorrow.

And it seems that we can do a bit more, although I need to recheck.


retint_kernel() no longer needs rcx == threadinfo, it doesn't check
TIF_NEED_RESCHED. This means we can shift/remove some GET_THREAD_INFO()'s
under retint_check.

Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/