Messages in this thread | | | From | Andy Lutomirski <> | Date | Mon, 3 Nov 2014 14:37:07 -0800 | Subject | Re: [tip:x86/asm] sched/x86_64: Don't save flags on context switch |
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On Mon, Nov 3, 2014 at 1:58 PM, Oleg Nesterov <oleg@redhat.com> wrote: > 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() ?
Seems reasonable to me. Want to write the patch?
> > 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.
We might get there from #MC or from any of a number of synchronous errors (#GP from xyz_safe, #PF from some atomic uaccess thing or a vmap fault, etc), and all of those have interrupts off.
--Andy
> > Oleg. >
-- Andy Lutomirski AMA Capital Management, LLC
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