Re: preemptible RCU bug (was Re: [git pull] scheduler changes forv2.6.25)

From: Ingo Molnar
Date: Sun Jan 27 2008 - 07:26:55 EST



* Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> wrote:

> > Sorry, no help available for this option yet.
>
> Good catch!!!
>
> This patch supplies help text for the "RCU implementation type" kernel
> configuration choice.

thanks applied to sched.git. (see the patch below - the config option is
in init/Kconfig in mainline, not in kernel/Kconfig.preempt)

Ingo

------------->
Subject: RCU: add help text for "RCU implementation type"
From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>

This patch supplies help text for the "RCU implementation type"
kernel configuration choice.

Reported-by: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---

init/Kconfig | 8 ++++++++
1 file changed, 8 insertions(+)

Index: linux/init/Kconfig
===================================================================
--- linux.orig/init/Kconfig
+++ linux/init/Kconfig
@@ -779,6 +779,14 @@ config PREEMPT_NOTIFIERS
choice
prompt "RCU implementation type:"
default CLASSIC_RCU
+ help
+ This allows you to choose either the classic RCU implementation
+ that is designed for best read-side performance on non-realtime
+ systems, or the preemptible RCU implementation for best latency
+ on realtime systems. Note that some kernel preemption modes
+ will restrict your choice.
+
+ Select the default if you are unsure.

config CLASSIC_RCU
bool "Classic RCU"
--
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