Re: [PATCH tip/core/rcu 0/6] rcu: fix synchronize_rcu_expedited(), update docs, improve perf

Ingo Molnar
2009-10-15T09:23:15Z

* Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:

> This patchset contains a bug fix, a performance improvement, and
> documentation updates:
>
> o Update Documentation/RCU/trace.txt to reflect recent changes
> (including the removal of rcupreempt.c).

i've applied this to the .33 queue.

>
> o Fix to the severe performance problem with excessive IPIs and
> lock contention in presence of very large (but legal) numbers
> of RCU callbacks (reported by Nick Piggin).

i've applied this to the .32 queue.

> o Stopgap fix for a bug in TREE_PREEMPT_RCU's implementation of
> synchronize_rcu_expedited(). This fix is correct, but no faster
> than synchronize_rcu().
>
> o Add exports for the updated synchronize_rcu_expedited()
> implementation, which moved from a static inline in
> include/linux/rcupdate.h to a separately compiled function
> in kernel/rcutree_plugin.h.

i've merged these two into the same commit and applied it to the .32
queue.

> o Add the new rnp->blocked_tasks field to the rcuhier trace file
> in debugfs.
>
> o Update the Documentation/RCU/trace.txt documentation to include
> the rnp->blocked_tasks tracing.

i've applied these to the .33 queue as well. (both tracing and
documentation is not urgent material.) I also did minor edits to the
changelogs.

Thanks Paul!

Ingo