watchdog: Disable watchdog when thresh is zero

This restores the previous behavior of softlock_thresh.

Currently, setting watchdog_thresh to zero causes the watchdog
kthreads to consume a lot of CPU.

In addition, the logic of proc_dowatchdog_thresh and
proc_dowatchdog_enabled has been factored into proc_dowatchdog.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/1306127423-3347-3-git-send-email-msb@chromium.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <20110517071018.GE22305@elte.hu>

1 files changed, 8 insertions, 4 deletions

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index c0bb32414b17..3dd0c46fa3bb 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -730,14 +730,16 @@ static struct ctl_table kern_table[] = {
                 .data           = &watchdog_enabled,
                 .maxlen         = sizeof (int),
                 .mode           = 0644,
-                .proc_handler   = proc_dowatchdog_enabled,
+                .proc_handler   = proc_dowatchdog,
+                .extra1         = &zero,
+                .extra2         = &one,
         },
         {
                 .procname       = "watchdog_thresh",
-                .data           = &softlockup_thresh,
+                .data           = &watchdog_thresh,
                 .maxlen         = sizeof(int),
                 .mode           = 0644,
-                .proc_handler   = proc_dowatchdog_thresh,
+                .proc_handler   = proc_dowatchdog,
                 .extra1         = &neg_one,
                 .extra2         = &sixty,
         },
@@ -755,7 +757,9 @@ static struct ctl_table kern_table[] = {
                 .data           = &watchdog_enabled,
                 .maxlen         = sizeof (int),
                 .mode           = 0644,
-                .proc_handler   = proc_dowatchdog_enabled,
+                .proc_handler   = proc_dowatchdog,
+                .extra1         = &zero,
+                .extra2         = &one,
         },
 #endif
 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)