[tip:perf/nmi] lockup_detector: Separate touch_nmi_watchdog code path from touch_watchdog

From: tip-bot for Don Zickus
Date: Thu May 13 2010 - 02:54:29 EST


Commit-ID: d7c547335fa6b0090fa09c46ea0e965ac273a27e
Gitweb: http://git.kernel.org/tip/d7c547335fa6b0090fa09c46ea0e965ac273a27e
Author: Don Zickus <dzickus@xxxxxxxxxx>
AuthorDate: Fri, 7 May 2010 17:11:51 -0400
Committer: Frederic Weisbecker <fweisbec@xxxxxxxxx>
CommitDate: Wed, 12 May 2010 23:55:55 +0200

lockup_detector: Separate touch_nmi_watchdog code path from touch_watchdog

When I combined the nmi_watchdog (hardlockup) and softlockup code, I
also combined the paths the touch_watchdog and touch_nmi_watchdog took.
This may not be the best idea as pointed out by Frederic W., that the
touch_watchdog case probably should not reset the hardlockup count.

Therefore the patch below falls back to the previous idea of keeping
the touch_nmi_watchdog a superset of the touch_watchdog case.

Signed-off-by: Don Zickus <dzickus@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Cyrill Gorcunov <gorcunov@xxxxxxxxx>
Cc: Eric Paris <eparis@xxxxxxxxxx>
Cc: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
LKML-Reference: <1273266711-18706-9-git-send-email-dzickus@xxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
---
kernel/watchdog.c | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index f1541b7..57b8e2c 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -31,6 +31,7 @@ int watchdog_enabled;
int __read_mostly softlockup_thresh = 60;

static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
+static DEFINE_PER_CPU(bool, watchdog_nmi_touch);
static DEFINE_PER_CPU(struct task_struct *, softlockup_watchdog);
static DEFINE_PER_CPU(struct hrtimer, watchdog_hrtimer);
static DEFINE_PER_CPU(bool, softlockup_touch_sync);
@@ -139,6 +140,7 @@ void touch_all_softlockup_watchdogs(void)

void touch_nmi_watchdog(void)
{
+ __get_cpu_var(watchdog_nmi_touch) = true;
touch_softlockup_watchdog();
}
EXPORT_SYMBOL(touch_nmi_watchdog);
@@ -201,10 +203,9 @@ void watchdog_overflow_callback(struct perf_event *event, int nmi,
struct pt_regs *regs)
{
int this_cpu = smp_processor_id();
- unsigned long touch_ts = per_cpu(watchdog_touch_ts, this_cpu);

- if (touch_ts == 0) {
- __touch_watchdog();
+ if (__get_cpu_var(watchdog_nmi_touch) == true) {
+ __get_cpu_var(watchdog_nmi_touch) = false;
return;
}

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