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

From: Rik van Riel
Date: Fri Feb 06 2015 - 22:54:13 EST


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 02/06/2015 06:15 PM, Frederic Weisbecker wrote:

> Just a few things then:
>
> 1) In this case rename context_tracking_user_enter/exit() to
> context_tracking_enter() and context_tracking_exit(), since it's
> not anymore about user only but about any generic context.
>
> 2) We have the "WARN_ON_ONCE(!current->mm);" condition that is a
> debug check specific to userspace transitions because kernel
> threads aren't expected to resume to userspace. Can we also expect
> that we never switch to/from guest from a kernel thread? AFAICS
> this happens from an ioctl (thus user task) in x86 for kvm. But I
> only know this case.
>
> 3) You might want to update a few comments that assume we only deal
> with userspace transitions.
>
> 4) trace_user_enter/exit() should stay user-transitions specific.

Paul, would you like me to send follow-up patches with the cleanups
suggested by Frederic, or would you prefer me to send a new series
with the cleanups integrated?

Frederic, I will also add the cleanup you suggested for patch 4/5.

- --
All rights reversed
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1

iQEcBAEBAgAGBQJU1Yw+AAoJEM553pKExN6DhycH/ifPeaRaFcj/BBKaDf7BmKAJ
cGMplf/vMtJA5DCFfZTmRp5Yb/9f3XBk8MU4Z+oWZFPB/msA8WkibhZtRGXpXXl9
7XgDXaXUuo++Axhb3SYHXEDhkPkhmfdjlctyr5ZUu3gHqkeWl6utv0t4anIBfo3Z
NdWG8yEhgKU6OyFppf3CH0Cm46xPN+pUyAFMgK9HbSfDkR3a9rMZ32aQq8fyV15e
LV4qE+/lPi7lyoLqbHmmU+pqp6iBqyQ9uFIDCRAoBBXF5jh0jxEynRubBn2D1HZJ
FBi+dBWGhAjRN05tuurvkwbJtcmTpnsHyNrmzNlAeop0Upc/5Vta43zN/nu1AFA=
=Z9mE
-----END PGP SIGNATURE-----
--
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/