Re: [PATCH tip/core/rcu 0/2] rcu: v2: more review feedback

[Josh Triplett <josh@joshtriplett.org>]

On Mon, Sep 28, 2009 at 07:45:51AM -0700, Paul E. McKenney wrote:
> This patchset applies the last of the review comments:
> 
> o	Whitespace fixes, updated comments, and code movement.
> 
> o	Improve an existing abstraction and introduce two additional
> 	abstractions for traversing the rcu_node tree.
> 
> Change since v1 (http://lkml.org/lkml/2009/9/27/17):
> 
> o	Update second patch's changelog
> 
> Issues remaining:
> 
> o	I can force hangs given sufficient rcutorture testing in
> 	conjunction with random CPU-hotplug operations.  I am working
> 	on a simpler interface between RCU and CPU hotplug that I
> 	believe will clear this up.
> 
> o	TREE_PREEMPT_RCU currently uses the TREE_RCU variant of
> 	synchronize_rcu_expedited, which is wrong.  I am working on
> 	an expedited variant for TREE_PREEMPT_RCU, but will fall
> 	back on synchronize_rcu() for the short term if it gives me
> 	much trouble.
> 
> o	The IPI hyperactivity from call_rcu() noted by Nick Piggin.
> 	I believe I have identified a clean design for a fix for this.
> 
> o	Make RCU less dependent on IPIs for forcing grace periods
> 	(but this might be best deferred to 2.6.33).
> 
> o	RCU priority boosting (2.6.33!).
> 
> o	TINY_PREEMPT_RCU (2.6.33!).
> 
> o	Squeeze another 400 bytes or so out of TINY_RCU (2.6.33!).
> 
> 
>  b/include/linux/rcupdate.h |   14 +++++------
>  b/kernel/rcutree.c         |   11 ++++-----
>  b/kernel/rcutree.h         |   12 ++++++++++
>  b/kernel/rcutree_plugin.h  |    5 ----
>  kernel/rcutree.c           |   53 +++++++++++++++++++++++----------------------
>  5 files changed, 52 insertions(+), 43 deletions(-)

For both patches:
Acked-by: Josh Triplett <josh@joshtriplett.org>