linux-kernel - Re: linux-next: Tree for April 14 (Call-traces: RCU/ACPI/WQ related?)

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Date:	Fri, 22 Apr 2011 11:40:54 +0200
From:	Sedat Dilek <sedat.dilek@...glemail.com>
To:	paulmck@...ux.vnet.ibm.com
Cc:	Stephen Rothwell <sfr@...b.auug.org.au>,
	linux-next@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: linux-next: Tree for April 14 (Call-traces: RCU/ACPI/WQ related?)

On Fri, Apr 22, 2011 at 2:50 AM, Paul E. McKenney
<paulmck@...ux.vnet.ibm.com> wrote:
> On Thu, Apr 21, 2011 at 04:47:31PM +0200, Sedat Dilek wrote:
>> On Thu, Apr 21, 2011 at 4:28 PM, Paul E. McKenney
>> <paulmck@...ux.vnet.ibm.com> wrote:
>> > On Thu, Apr 21, 2011 at 02:49:37PM +0200, Sedat Dilek wrote:
>> >> On Thu, Apr 21, 2011 at 12:24 PM, Sedat Dilek
>> >> <sedat.dilek@...glemail.com> wrote:
>
> [ . . . ]
>
>> >> Here the results from the 2nd-run (PREEMPT_RCU enabled).
>> >
>> > OK, and the grace periods clearly stopped advancing early on.
>> >
>> > Beyond that point, the per-CPU kthread is blocked, but RCU has some
>> > work for it to do.  So someone has called invoke_rcu_cpu_kthread(),
>> > but rcu_cpu_kthread() is still blocked.  I don't see a bug right
>> > off-hand, but it is early in the morning for me, so I might easily
>> > be missing something.
>> >
>> > Hmmm...
>> >
>> > The synchronization between these two assumes that the per-CPU
>> > kthread is always bound to the respective CPU, so if was somehow
>> > being migrated off, that might explain these results.
>> >
>> > I will add some more diagnostics, test them locally, then push
>> > out an update.  Seem reasonable?
>> >
>> > And thank you again for the testing!!!
>>
>> Ping me when you have new stuff for testing.
>> Tomorrow (friday), here is public holiday and monday, too.
>> So a looong weekend.
>
> ;-)
>
> OK, I have a new sedat.2011.04.21a branch in the -rcu git tree:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu.git
>
> This is against 2.6.39-rc3, as before.  (Yes, I do need to rebase to
> 2.6.39-rc4, but didn't want to change any more than I had to.)
>
> I also have an updated script, which is attached.  The output is similar
> to the earlier one, and it operated is pretty much the same way.
>
> Have a great weekend, and I look forward to seeing what shows up on
> this round.  I confess to still being quite puzzled!
>
>                                                        Thanx, Paul
>

Here are the results of the Sedat's vote (European song contest :-)).

- Sedat -

Download attachment "for-paulk-3.tar.xz" of type "application/octet-stream" (25348 bytes)

Download attachment "for-paulk-3.tar.xz.sha256sum" of type "application/octet-stream" (85 bytes)