From: Keshavamurthy Anil S <anil.s.keshavamurthy@intel.com>
To: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: SystemTAP <systemtap@sources.redhat.com>
Subject: Re: [RFC/PATCH] replace preempt_* calls with rcu_read_* variants
Date: Tue, 14 Mar 2006 22:12:00 -0000 [thread overview]
Message-ID: <20060314141207.A7579@unix-os.sc.intel.com> (raw)
In-Reply-To: <20060314134415.GA16136@in.ibm.com>; from ananth@in.ibm.com on Tue, Mar 14, 2006 at 05:44:15AM -0800
On Tue, Mar 14, 2006 at 05:44:15AM -0800, Ananth N Mavinakayanahalli wrote:
>
> Hi,
>
> Can somebody please remind me why we are not using
> rcu_read_unlock/lock()
> to RCU protect the kprobe handlers, instead, are using
> preempt_disable/enable()?
"In some realtime-friendly RCU implementations, the RCU read-side critical
sections do not disable preemption. So, if you are using synchronize_sched()
on the update side, you need to use preempt_disable() (or some other
primitive that disables preemption, for example, any of the primitives
that disables hardware interrupts) on the read side."
http://www.ussg.iu.edu/hypermail/linux/kernel/0510.2/0537.html
-thanks,
-Anil
prev parent reply other threads:[~2006-03-14 22:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-14 13:44 Ananth N Mavinakayanahalli
2006-03-14 14:00 ` Mathieu Desnoyers
2006-03-14 22:12 ` Keshavamurthy Anil S [this message]
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