Re: [PATCH v3 5/5] x86/entry/64: Bypass enter_from_user_mode on non-context-tracking boots

Frederic Weisbecker
2015-11-13T15:26:17Z

On Thu, Nov 12, 2015 at 12:59:04PM -0800, Andy Lutomirski wrote:
> On CONFIG_CONTEXT_TRACKING kernels that have context tracking
> disabled at runtime (which includes most distro kernels), we still
> have the overhead of a call to enter_from_user_mode in interrupt and
> exception entries.
>
> If jump labels are available, this uses the jump label
> infrastructure to skip the call.

Looks good. But why are we still calling context tracking code on IRQs at all?

Thanks.