From: Dave Jones <davej@codemonkey.org.uk>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>,
Josh Triplett <josh@joshtriplett.org>,
sasha.levin@oracle.com, fweisbec@gmail.com
Subject: Re: 4.2-rc5 rcu stalls.
Date: Mon, 3 Aug 2015 17:55:35 -0400 [thread overview]
Message-ID: <20150803215535.GA13717@codemonkey.org.uk> (raw)
In-Reply-To: <20150803213723.GN27280@linux.vnet.ibm.com>
On Mon, Aug 03, 2015 at 02:37:23PM -0700, Paul E. McKenney wrote:
> On Mon, Aug 03, 2015 at 05:08:35PM -0400, Dave Jones wrote:
> > [ 2120.855128] Tasks blocked on level-0 rcu_node (CPUs 0-3): P1497
> > [ 2120.855263] (detected by 2, t=65002 jiffies, g=78835, c=78834, q=0)
> > [ 2120.855403] trinity-watchdo R running task 14336 1497 1496 0x00080000
> > [ 2120.855563] ffff8804b94e3c88 ffffffffa17fa0b0 ffff8805010a1b40 ffff8804f58b51c0
> > [ 2120.855728] ffff8805010a1b40 ffff8804b94e3c78 0000000000000000 ffff8804b94e4000
> > [ 2120.855893] 0000000000000001 0000000000000001 0000000000000002 ffff8804b94e3ca8
> > [ 2120.856062] Call Trace:
> > [ 2120.856116] [<ffffffffa17fa0b0>] ? preempt_schedule_irq+0x40/0xa0
> > [ 2120.856252] [<ffffffffa17fa0b6>] preempt_schedule_irq+0x46/0xa0
>
> Sasha Levin (CCed) was having roughly similar stalls, and found that
> reverting b30f0e3ffedf (sched/preempt: Optimize preemption operations
> on __schedule() callers) made the stalls go away. Does that help in
> your case?
Ugh, that doesn't revert cleanly. Got something handy ?
The curious thing is why I've only just started seeing these.
I've had that machine for a month now, so it's been fuzzing since ~4.1,
and until yesterday I'd not seen this at all.
Dave
next prev parent reply other threads:[~2015-08-03 21:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-03 21:08 4.2-rc5 rcu stalls Dave Jones
2015-08-03 21:37 ` Paul E. McKenney
2015-08-03 21:55 ` Dave Jones [this message]
2015-08-03 22:03 ` Paul E. McKenney
2015-08-04 4:54 ` Sasha Levin
2015-08-05 0:12 ` Dave Jones
2015-08-05 12:37 ` Frederic Weisbecker
2015-08-05 13:18 ` Dave Jones
2015-08-05 14:38 ` Frederic Weisbecker
2015-08-05 14:46 ` Dave Jones
2015-08-06 4:15 ` Dave Jones
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