Re: [PATCH 1/5] rcu,nohz: add state parameter to context_tracking_user_enter/exit

From: Frederic Weisbecker
Date: Fri Feb 06 2015 - 13:23:10 EST


On Fri, Feb 06, 2015 at 01:20:21PM -0500, Rik van Riel wrote:
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> On 02/06/2015 12:22 PM, Frederic Weisbecker wrote:
> > On Thu, Feb 05, 2015 at 03:23:48PM -0500, riel@xxxxxxxxxx wrote:
> >> From: Rik van Riel <riel@xxxxxxxxxx>
> >>
> >> Add the expected ctx_state as a parameter to
> >> context_tracking_user_enter and context_tracking_user_exit,
> >> allowing the same functions to not just track kernel <> user
> >> space switching, but also kernel <> guest transitions.
> >>
> >> Signed-off-by: Rik van Riel <riel@xxxxxxxxxx>
> >
> > You should consider using guest_enter() and guest_exit() instead.
> > These are context tracking APIs too but specifically for guest.
>
> What do you mean instead? KVM already uses those.
>
> I just wanted to avoid duplicating the code...

I mean you can call rcu_user APIs directly from guest_enter/exit.
You don't really need to call the context_tracking_user functions
since guest_enter/guest_exit already handle the vtime accounting.

>
> - --
> All rights reversed
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