From: NeilBrown <neilb@suse.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Thierry Reding <thierry.reding@gmail.com>,
Shaohua Li <shli@kernel.org>, Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-next@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: linux-next: manual merge of the tip tree
Date: Thu, 17 Oct 2013 12:28:59 +1100 [thread overview]
Message-ID: <20131017122859.67432627@notabene.brown> (raw)
In-Reply-To: <20131016205207.GE10651@twins.programming.kicks-ass.net>
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On Wed, 16 Oct 2013 22:52:07 +0200 Peter Zijlstra <peterz@infradead.org>
wrote:
> Hey Neil;
>
> it looks like its one of your patches isn't it?
>
> http://www.spinics.net/lists/raid/msg44100.html
> http://www.spinics.net/lists/raid/msg44101.html
>
> Given that I can't find them in a lkml archive means nobody's ever seen
> those patches.
>
> Anyway; has that 3/3 patch ever been ran with lockdep enabled?
I always run with lockdep enabled, and I have done at least basic testing
(I've been on leave for a few weeks and don't remember exactly where I got
to).
And I haven't seen any lockdep reports.
>
> Stuff like:
>
> + for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
> + spin_lock_init(conf->hash_locks + i);
>
> And:
>
> +static void __lock_all_hash_locks(struct r5conf *conf)
> +{
> + int i;
> + for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
> + spin_lock(conf->hash_locks + i);
> +}
>
> Tends to complain real loud.
Why is that?
Because "conf->hash_locks + i" gets used as the "name" of the lockdep map for
each one, and when they are all locked it looks like nested locking??
the lock_all_hash_locks doesn't get called very often and my testing mustn't
have got that far. I just tried something that would trigger the
"lock_all_device_hash_locks_irq" (as it is in the current version) and it
went "splat" just as you said it would.
Thanks.
Do you have a suggestion for how to make this work?
Would
spin_lock_nested(conf->hash_locks + i, i)
do the trick?
Thanks,
NeilBrown
>
> This leaves one to wonder...
> 'fancy' locking scheme:1, validation effort:0
>
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next prev parent reply other threads:[~2013-10-17 1:29 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-16 18:51 linux-next: Tree for Oct 16 Thierry Reding
2013-10-16 18:51 ` linux-next: manual merge of the tip tree Thierry Reding
2013-10-16 20:06 ` Peter Zijlstra
2013-10-16 20:14 ` Peter Zijlstra
2013-10-16 20:31 ` NeilBrown
2013-10-16 20:35 ` Peter Zijlstra
2013-10-16 20:51 ` Thierry Reding
2013-10-16 21:00 ` Peter Zijlstra
2013-10-16 20:52 ` Peter Zijlstra
2013-10-17 1:28 ` NeilBrown [this message]
2013-10-17 9:23 ` Peter Zijlstra
2013-10-22 2:09 ` NeilBrown
2013-10-16 20:40 ` Thierry Reding
2013-10-16 20:44 ` Thierry Reding
2013-10-16 21:30 ` Peter Zijlstra
2013-10-17 1:29 ` NeilBrown
2013-10-16 18:51 ` linux-next: manual merge of the kvm-arm tree Thierry Reding
2013-10-16 18:58 ` Marc Zyngier
2013-10-16 19:02 ` Christoffer Dall
2013-10-16 19:04 ` Thierry Reding
2013-10-16 19:09 ` Christoffer Dall
2013-10-17 14:55 ` Gleb Natapov
2013-10-17 16:53 ` Christoffer Dall
2013-10-16 21:48 ` linux-next: Tree for Oct 16 (net/sched/em_ipset.c) Randy Dunlap
2013-10-16 22:39 ` Stephen Hemminger
2013-10-17 0:21 ` Randy Dunlap
2013-10-17 0:29 ` [PATCH net-next] em_ipset: use dev_net() accessor Stephen Hemminger
2013-10-18 20:23 ` David Miller
2013-10-17 0:58 ` linux-next: Tree for Oct 16 Randy Dunlap
2013-10-17 5:12 ` Guenter Roeck
-- strict thread matches above, loose matches on Subject: below --
2013-10-24 16:31 linux-next: Tree for Oct 24 Thierry Reding
2013-10-25 13:03 ` linux-next: manual merge of the c6x tree Thierry Reding
2013-10-25 13:03 ` linux-next: manual merge of the tip tree Thierry Reding
2013-10-25 13:25 ` Will Deacon
2013-10-26 8:40 ` Ingo Molnar
2013-10-26 14:01 ` Will Deacon
2013-10-27 7:12 ` Ingo Molnar
2013-10-27 10:00 ` Russell King - ARM Linux
2013-10-28 7:47 ` Thierry Reding
2013-10-28 8:45 ` Russell King - ARM Linux
2013-10-17 21:23 Mark Brown
2013-10-17 21:50 ` Cyrill Gorcunov
2013-09-30 11:26 linux-next: manual merge of the bcon tree Thierry Reding
2013-09-30 11:26 ` linux-next: manual merge of the tip tree Thierry Reding
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