Re: [GIT PULL rcu/next] rcu commits for 2.6.40

[Paul E. McKenney]

On Mon, May 09, 2011 at 02:09:21PM -0700, Yinghai Lu wrote:
> On Mon, May 9, 2011 at 12:36 AM, Ingo Molnar <mingo@xxxxxxx> wrote:
> >
> > * Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> wrote:
> >
> >> Hello, Ingo,
> >>
> >> This pull request covers RCU chnages for 2.6.40.  The major new features
> >> are RCU priority boosting and the addition of kfree_rcu(), the latter
> >> courtesy of Lai Jiangshan.  These two features cover well over half
> >> of the commits.  There are a number of smaller features and bug fixes.
> >> All have been sent to LKML in the following batches:
> >>
> >> 0.    https://lkml.org/lkml/2011/2/22/660: RCU priority boosting preview
> >> 1.    https://lkml.org/lkml/2011/5/1/19: RCU priority boosting, kfree_rcu()
> >> 2.    https://lkml.org/lkml/2011/5/2/40: More uses of kfree_rcu()
> >> 3.    https://lkml.org/lkml/2011/5/8/60: miscellaneous
> >>
> >> The kfree_rcu() uses in the pull request have Acked-by:s from the
> >> maintainers.  I have some additional kfree_rcu() requests that lack
> >> Acked-by:s, and I will deal with these later.
> >>
> >> These channges are available in the -rcu git repository at:
> >>
> >>   git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu.git rcu/next
> >
> > Pulled, thanks a lot Paul!
> >
> 
> it seems with this one in tip, my 8 sockets test setup will report cpu stall.
> 
> after hard code to enable rcu_cpu_stall_suppress
> 
> Index: linux-2.6/kernel/rcutree.c
> ===================================================================
> --- linux-2.6.orig/kernel/rcutree.c
> +++ linux-2.6/kernel/rcutree.c
> @@ -174,7 +174,7 @@ module_param(blimit, int, 0);
>  module_param(qhimark, int, 0);
>  module_param(qlowmark, int, 0);
> 
> -int rcu_cpu_stall_suppress __read_mostly;
> +int rcu_cpu_stall_suppress __read_mostly = 1;
>  module_param(rcu_cpu_stall_suppress, int, 0644);
> 
>  static void force_quiescent_state(struct rcu_state *rsp, int relaxed);
> 
> will get system hang after pnp ACPI init.

Could you please send the stack traces from the RCU CPU stall?  Also,
you do have ce31332d3c77532d6ea97ddcb475a2b02dd358b4 applied, correct?

							Thanx, Paul
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