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

From: Paul E. McKenney
Date: Tue May 10 2011 - 15:32:27 EST


On Tue, May 10, 2011 at 11:04:57AM -0700, Yinghai Lu wrote:
> On 05/10/2011 01:56 AM, Paul E. McKenney wrote:
> > 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
>
> Do not have time to bisect it at this point.

Could you please send the stack traces from the RCU CPU stall?

Thanx, Paul

> can you prepare clean revert patch for following commit to test?
>
> commit a00e0d714fbded07a7a2254391ce9ed5a5cb9d82
> Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> Date: Tue Feb 8 17:14:39 2011 -0800
>
> rcu: Remove conditional compilation for RCU CPU stall warnings
>
>
> Thanks
>
> Yinghai Lu
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