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Date: Sat, 23 Aug 2014 20:23:39 -0700
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Pranith Kumar <pranith@gatech.edu>
Cc: Amit Shah <amit.shah@redhat.com>, LKML <linux-kernel@vger.kernel.org>,
        Rik van Riel <riel@redhat.com>, Ingo Molnar <mingo@kernel.org>,
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        =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>,
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Subject: Re: [PATCH tip/core/rcu 1/2] rcu: Parallelize and economize NOCB
 kthread wakeups
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On Sat, Aug 23, 2014 at 08:26:10PM -0400, Pranith Kumar wrote:
> On Sat, Aug 23, 2014 at 12:51 PM, Paul E. McKenney
> <paulmck@linux.vnet.ibm.com> wrote:
> 
> > It might well!  Another possibility is that the early_initcall function
> > doing the synchronize_rcu() is happening before the early_initcall
> > creating the RCU grace-period kthreads.
> >
> > Seems like we need to close both holes.  Let's see how your patch works
> > for Amit, and I am testing a patch for the possible early_initcall
> > ordering issue.
> 
> I checked the init call which is calling synchronize_rcu():
> subsys_initcall(pm_sysrq_init); this is being called after
> early_initcall.
> 
> The order of initcalls is early, core, postcore, arch, subsys, fs,
> device, late. So I guess that is ok.
> 
> I wonder why it was not showing up in 12.04. I have a dual boot. Will
> test it out and see if I can find something.

Me, I am wondering about 7,000 callbacks being registered during early
boot time.  ;-)

							Thanx, Paul