From: Peter Zijlstra <peterz@infradead.org>
To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org,
LKML <linux-kernel@vger.kernel.org>,
davidlohr@hp.com, paulus@samba.org, tglx@linutronix.de,
torvalds@linux-foundation.org, mingo@kernel.org
Subject: Re: Tasks stuck in futex code (in 3.14-rc6)
Date: Wed, 19 Mar 2014 16:47:05 +0100 [thread overview]
Message-ID: <20140319154705.GB8557@laptop.programming.kicks-ass.net> (raw)
In-Reply-To: <20140319152619.GB10406@linux.vnet.ibm.com>
On Wed, Mar 19, 2014 at 08:56:19PM +0530, Srikar Dronamraju wrote:
> There are 332 tasks all stuck in futex_wait_queue_me().
> I am able to reproduce this consistently.
>
> Infact I can reproduce this if the java_constraint is either node, socket, system.
> However I am not able to reproduce if java_constraint is set to core.
What's any of that mean?
> I ran git bisect between v3.12 and v3.14-rc6 and found that
>
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b0c29f79ecea0b6fbcefc999e70f2843ae8306db
>
> commit b0c29f79ecea0b6fbcefc999e70f2843ae8306db
> Author: Davidlohr Bueso <davidlohr@hp.com>
> Date: Sun Jan 12 15:31:25 2014 -0800
>
> futexes: Avoid taking the hb->lock if there's nothing to wake up
>
> was the commit thats causing the threads to be stuck in futex.
>
> I reverted b0c29f79ecea0b6fbcefc999e70f2843ae8306db on top of v3.14-rc6 and confirmed that
> reverting the commit solved the problem.
Joy,.. let me look at that with ppc in mind.
next prev parent reply other threads:[~2014-03-19 15:47 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-19 15:26 Tasks stuck in futex code (in 3.14-rc6) Srikar Dronamraju
2014-03-19 15:47 ` Peter Zijlstra [this message]
2014-03-19 16:09 ` Srikar Dronamraju
2014-03-19 17:08 ` Peter Zijlstra
2014-03-19 18:06 ` Davidlohr Bueso
2014-03-20 5:33 ` Srikar Dronamraju
2014-03-20 5:56 ` Davidlohr Bueso
2014-03-20 10:08 ` Srikar Dronamraju
2014-03-20 15:06 ` Davidlohr Bueso
2014-03-20 16:31 ` Davidlohr Bueso
2014-03-20 20:23 ` Benjamin Herrenschmidt
2014-03-20 16:41 ` Linus Torvalds
2014-03-20 17:18 ` Davidlohr Bueso
2014-03-20 17:42 ` Linus Torvalds
2014-03-20 18:03 ` Davidlohr Bueso
2014-03-20 18:16 ` Linus Torvalds
2014-03-20 18:36 ` Linus Torvalds
2014-03-20 19:08 ` Davidlohr Bueso
2014-03-20 19:25 ` Linus Torvalds
2014-03-20 20:20 ` Davidlohr Bueso
2014-03-20 20:36 ` Linus Torvalds
2014-03-21 4:55 ` Srikar Dronamraju
2014-03-21 5:24 ` Linus Torvalds
2014-03-22 2:27 ` Srikar Dronamraju
2014-03-22 3:36 ` Davidlohr Bueso
2014-03-20 7:23 ` Peter Zijlstra
2014-03-19 16:04 ` Linus Torvalds
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