From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: linux-kernel@vger.kernel.org, mingo@redhat.com, hpa@zytor.com,
paul.mckenney@linaro.org, rmk+kernel@arm.linux.org.uk,
weber@corscience.de, tglx@linutronix.de,
linux-tip-commits@vger.kernel.org
Subject: Re: [tip:core/urgent] rcu: avoid pointless blocked-task warnings
Date: Sat, 15 Jan 2011 16:15:16 -0800 [thread overview]
Message-ID: <20110116001516.GB2229@linux.vnet.ibm.com> (raw)
In-Reply-To: <20110115142857.GA8610@elte.hu>
On Sat, Jan 15, 2011 at 03:28:57PM +0100, Ingo Molnar wrote:
>
> * tip-bot for Paul E. McKenney <paul.mckenney@linaro.org> wrote:
>
> > Commit-ID: b24efdfdf679cf9b05947c531971905fc727dd40
> > Gitweb: http://git.kernel.org/tip/b24efdfdf679cf9b05947c531971905fc727dd40
> > Author: Paul E. McKenney <paul.mckenney@linaro.org>
> > AuthorDate: Wed, 12 Jan 2011 14:18:11 -0800
> > Committer: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> > CommitDate: Fri, 14 Jan 2011 04:58:08 -0800
> >
> > rcu: avoid pointless blocked-task warnings
> >
> > If the RCU callback-processing kthread has nothing to do, it parks in
> > a wait_event(). If RCU remains idle for more than two minutes, the
> > kernel complains about this. This commit changes from wait_event()
> > to wait_event_interruptible() to prevent the kernel from complaining
> > just because RCU is idle.
>
> Btw., a sidenote, it's not just about the blocked-tasks lockup detector warning,
> uninterruptible sleeps will also artificially inflate the load average of the box,
> +1.0 per such task. So it's definitely a bug to sleep for a very long time
> uninterruptible.
Good point, and I have made the corresponding change in the in-progress
TREE_PREEMPT_RCU variant of RCU priority boosting. Some thought will be
required when merging SRCU into the Tiny and Tree RCU implementations. ;-)
Thanx, Paul
prev parent reply other threads:[~2011-01-16 0:15 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <tip-b24efdfdf679cf9b05947c531971905fc727dd40@git.kernel.org>
2011-01-15 14:28 ` [tip:core/urgent] rcu: avoid pointless blocked-task warnings Ingo Molnar
2011-01-16 0:15 ` Paul E. McKenney [this message]
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