From: Tejun Heo <tj@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
RT <linux-rt-users@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Clark Williams <clark@redhat.com>,
"Paul E. McKenney" <paulmck@us.ibm.com>
Subject: Re: question about disabling interrupts for workqueue pool?
Date: Tue, 25 Jun 2013 16:01:29 -0700 [thread overview]
Message-ID: <20130625230129.GA30407@mtj.dyndns.org> (raw)
In-Reply-To: <1372200754.18733.236.camel@gandalf.local.home>
Hello, Steven.
On Tue, Jun 25, 2013 at 06:52:34PM -0400, Steven Rostedt wrote:
> Now my question is, are those local_irq_*() calls just for synchronizing
> with sched RCU? If so, can you use rcu_read_lock_sched() instead?
Hmmm... using local_irq_disable/enable() is more consistent as
irq-safe locks are used widely in workqueue. Also, using
rcu_read_lock_sched() would mean that we'll have
spin_lock_irq_save/restore() nested inside preempt_disable/enable(),
which is a bit silly in upstream kernel.
That said, both paths you pointed out are rather cold, so I don't
think it'd matter. Please feel free to send a patch with comment
explaining why local irq flipping, which fits better there, isn't
being used.
Thanks.
--
tejun
next prev parent reply other threads:[~2013-06-25 23:01 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-25 22:52 question about disabling interrupts for workqueue pool? Steven Rostedt
2013-06-25 23:01 ` Tejun Heo [this message]
2013-06-25 23:19 ` Steven Rostedt
2013-06-25 23:26 ` Tejun Heo
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