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

From: Josh Triplett
Date: Thu Feb 02 2012 - 21:44:10 EST


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@xxxxxxxxxxxxxxxx>
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