Re: [PATCH RFC 0/3] Fix cpuidle_idle_call() RCU usage

[Josh Triplett <josh@joshtriplett.org>]

On Thu, Feb 02, 2012 at 05:12:08PM -0800, Paul E. McKenney wrote:
> This patch series is a second attempt to fix the idle-loop uses of RCU,
> see https://lkml.org/lkml/2012/2/1/741 for v1.  Where the first series
> attempted to drive rcu_idle_enter() and rcu_idle_exit() further down
> into the Linux kernels multitude of idle loops, this patch instead
> marks specific idle-loop operations containing RCU read-side critical
> sections, as suggested by Nicolas Pitre and Steven Rostedt.  The possibility
> of code shared between idle and non-idle also requires the ability to nest
> rcu_idle_enter() calls.  The individual patches are as follows:
> 
> 1.	Allow nesting of rcu_idle_enter() and rcu_idle_exit().
> 2.	Add an RCU_NONIDLE() macro to enclose idle-loop code that
> 	contains RCU read-side critical sections.
> 3.	Use RCU_NONIDLE() to protect cpuidle_idle_call()'s tracepoints.
> 
> This patchset has the distinct advantage of avoiding touching any
> architecture-specific code.  ;-)
> 
> 							Thanx, Paul
> 
> ------------------------------------------------------------------------
> 
>  b/drivers/cpuidle/cpuidle.c |   12 ++++++++----
>  b/include/linux/rcupdate.h  |   27 +++++++++++++++++++++++++++
>  b/kernel/rcu.h              |   18 +++++++++++++++++-
>  b/kernel/rcutiny.c          |   16 ++++++++++++----
>  b/kernel/rcutree.c          |   19 +++++++++++++------
>  kernel/rcutiny.c            |    2 ++
>  kernel/rcutree.c            |    2 ++
>  7 files changed, 81 insertions(+), 15 deletions(-)

Looks good to me.  Much cleaner.

Reviewed-by: Josh Triplett <josh@joshtriplett.org>