Re: config RCU_EQS_DEBUG

From: Paul E. McKenney
Date: Fri Jul 03 2015 - 12:01:15 EST


On Fri, Jul 03, 2015 at 10:07:45AM +0200, Jean Delvare wrote:
> Hi Paul,
>
> You just introduced a Linux kernel configuration option named
> RCU_EQS_DEBUG. Its short description is "Use this when adding any sort
> of NO_HZ support to your arch".
>
> I'm afraid this is a bad way to briefly explain what the option
> actually does (which is what the short description is for.) A sentence
> like "use this when adding any sort of NO_HZ support to your arch"
> should go in the help text, not the short description. The short
> description should be something like along the lines of "Enable
> consistency checks for RCU", for example.
>
> Additionally I see some inconsistency in the fact that this option
> defaults to n but the help text says "Say Y if you are unsure". BTW,
> option RCU_CPU_STALL_INFO is equally inconsistent with a default y and
> "say N if you are unsure" in the help text.

Hello, Jean,

I have the following queued, which should address your first point.

Would adding "default y" address your other point?

On RCU_CPU_STALL_INFO, I have a patch queued for v4.3 that eliminates
this Kconfig option completely.

Thanx, Paul

------------------------------------------------------------------------

rcu: Clarify CONFIG_RCU_EQS_DEBUG help text

Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 6be521990d61..80efaade5e59 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1360,7 +1360,7 @@ config RCU_TRACE
Say N if you are unsure.

config RCU_EQS_DEBUG
- bool "Use this when adding any sort of NO_HZ support to your arch"
+ bool "Provide debugging asserts for adding NO_HZ support to an arch"
depends on DEBUG_KERNEL
help
This option provides consistency checks in RCU's handling of

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