Re: [PATCH 1/2] watchdog: Introduce update_arch_nmi_watchdog

From: Babu Moger
Date: Fri Oct 07 2016 - 10:55:27 EST

On 10/6/2016 11:34 PM, Sam Ravnborg wrote:
On Thu, Oct 06, 2016 at 03:16:42PM -0700, Babu Moger wrote:
Currently we do not have a way to enable/disable arch specific
watchdog handlers if it was implemented by any of the architectures.

This patch introduces new function update_arch_nmi_watchdog
which can be used to enable/disable architecture specific NMI
watchdog handlers. Also exposes watchdog_enabled variable outside
so that arch specific nmi watchdogs can use it to implement
enalbe/disable behavour.

Signed-off-by: Babu Moger <babu.moger@xxxxxxxxxx>
include/linux/nmi.h | 1 +
kernel/watchdog.c | 16 +++++++++++++---
2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index 4630eea..01b4830 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -66,6 +66,7 @@ static inline bool trigger_allbutself_cpu_backtrace(void)
u64 hw_nmi_get_sample_period(int watchdog_thresh);
+extern unsigned long watchdog_enabled;
The extern is within an #ifdef, but the definition later is
valid alway.
So extern definition should be outside the #ifdef to match the
actual implementation.

Ok. Sure.

To manipulate / read watchdog_enabled two constants are used:

Sure. I will bring these definitions to nmi.h from watchdog.c

They should be visible too, so uses do not fall into the trap
and uses constants (like in patch 2).

Will re-post v2 version with these changes. Thanks for the comments.