watchdog: Reduce message verbosity

PATCH Superseded Sinan Kaya 3 participants 6 messages Jul 30, 2018 – Aug 2, 2018

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Sinan Kaya

author

2018-07-30 19:09 UTC #0 lore raw

PATCH 1/1 watchdog: Reduce message verbosity

Reducing the verbosity level to debug for people that are interested in debugging watchdog issues.

[    0.152492] NMI watchdog: Perf event create on CPU 0 failed with -2
[    0.156002] NMI watchdog: Perf NMI watchdog permanently disabled

Signed-off-by Sinan Kaya <[email protected]>

---
 kernel/watchdog_hld.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

kernel/watchdog_hld.c +2 -2

index e449a23e9d59..1f7020d65d0a 100644
@@ -175,8 +175,8 @@ static int hardlockup_detector_event_create(void)
 	evt = perf_event_create_kernel_counter(wd_attr, cpu, NULL,
 					       watchdog_overflow_callback, NULL);
 	if (IS_ERR(evt)) {
-		pr_info("Perf event create on CPU %d failed with %ld\n", cpu,
-			PTR_ERR(evt));
+		pr_debug("Perf event create on CPU %d failed with %ld\n", cpu,
+			 PTR_ERR(evt));
 		return PTR_ERR(evt);
 	}
 	this_cpu_write(watchdog_ev, evt);

Signature · 1 line

2.17.1

Don Zickus

2018-07-30 19:28 UTC #1 lore raw

Quoted 5 lines · Sinan Kaya

Reducing the verbosity level to debug for people that are interested in debugging watchdog issues.
[    0.152492] NMI watchdog: Perf event create on CPU 0 failed with -2
[    0.156002] NMI watchdog: Perf NMI watchdog permanently disabled

Hi Sinan,

Any reason why? Usually when the 'perf event' fails, that indicates a system problem. And most folks don't boot with the 'debug' option. This means these unusual failures are hidden and become difficult to debug later when it propagates.

Or are you running the watchdog in a different configuration such that this is a common nuisance that you are trying to suppress?

Cheers,
Don

Quoted 24 lines

Signed-off-by Sinan Kaya <[email protected]>

---
 kernel/watchdog_hld.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

kernel/watchdog_hld.c +2 -2

index e449a23e9d59..1f7020d65d0a 100644
@@ -175,8 +175,8 @@ static int hardlockup_detector_event_create(void)
 	evt = perf_event_create_kernel_counter(wd_attr, cpu, NULL,
 					       watchdog_overflow_callback, NULL);
 	if (IS_ERR(evt)) {
-		pr_info("Perf event create on CPU %d failed with %ld\n", cpu,
-			PTR_ERR(evt));
+		pr_debug("Perf event create on CPU %d failed with %ld\n", cpu,
+			 PTR_ERR(evt));
 		return PTR_ERR(evt);
 	}
 	this_cpu_write(watchdog_ev, evt);

Signature · 1 line

2.17.1

Sinan Kaya

author

2018-07-30 19:43 UTC #2 lore raw

Hi Don,

Quoted 8 lines · Don Zickus

Quoted 2 lines
[    0.152492] NMI watchdog: Perf event create on CPU 0 failed with -2
[    0.156002] NMI watchdog: Perf NMI watchdog permanently disabled
Hi Sinan,
Any reason why? Usually when the 'perf event' fails, that indicates a system problem. And most folks don't boot with the 'debug' option. This means these unusual failures are hidden and become difficult to debug later when it propagates.

Sorry, I should have been more clear. I'm only suppressing the first error message.

[    0.152492] NMI watchdog: Perf event create on CPU 0 failed with -2

Second message is still visible during boot. User knows that NMI watchdog is disabled.

[    0.156002] NMI watchdog: Perf NMI watchdog permanently disabled

Code is trying to probe the platform capabilities and is failing because of missing PMU in the system. If someone is interested in finding out why watchdog was disabled, they can turn on the debug message level.

Quoted 3 lines

Or are you running the watchdog in a different configuration such that this is a common nuisance that you are trying to suppress?

Yup, system doesn't support PMU.

Quoted 4 lines

Cheers,
Don

Sinan

Don Zickus

Acked-by

2018-08-01 15:59 UTC #3 lore raw

Quoted 28 lines · Sinan Kaya

Hi Don,
Quoted 8 lines · Don Zickus
Quoted 2 lines
[    0.152492] NMI watchdog: Perf event create on CPU 0 failed with -2
[    0.156002] NMI watchdog: Perf NMI watchdog permanently disabled
Hi Sinan,
Any reason why? Usually when the 'perf event' fails, that indicates a system problem. And most folks don't boot with the 'debug' option. This means these unusual failures are hidden and become difficult to debug later when it propagates.
Sorry, I should have been more clear. I'm only suppressing the first error message.
[    0.152492] NMI watchdog: Perf event create on CPU 0 failed with -2
Second message is still visible during boot. User knows that NMI watchdog is disabled.
[    0.156002] NMI watchdog: Perf NMI watchdog permanently disabled
Code is trying to probe the platform capabilities and is failing because of missing PMU in the system. If someone is interested in finding out why watchdog was disabled, they can turn on the debug message level.
Quoted 1 line

Quoted 4 lines

Quoted 2 lines
Or are you running the watchdog in a different configuration such that this is a common nuisance that you are trying to suppress?
Yup, system doesn't support PMU.

Hi Sinan,

Oh, I see. You are just trying to hide the always failing probe. It seems to make sense.

Acked-by Don Zickus <[email protected]>

Thomas Gleixner

2018-08-02 12:18 UTC #4 lore raw

In reply to Sinan Kaya

Quoted 5 lines · Sinan Kaya

Reducing the verbosity level to debug for people that are interested in debugging watchdog issues.
[    0.152492] NMI watchdog: Perf event create on CPU 0 failed with -2
[    0.156002] NMI watchdog: Perf NMI watchdog permanently disabled

This changelog is utterly useless.

Thanks,

tglx

Sinan Kaya

author

2018-08-02 14:44 UTC #5 lore raw

Quoted 9 lines · Thomas Gleixner

Quoted 5 lines · Sinan Kaya
Reducing the verbosity level to debug for people that are interested in debugging watchdog issues.
[    0.152492] NMI watchdog: Perf event create on CPU 0 failed with -2
[    0.156002] NMI watchdog: Perf NMI watchdog permanently disabled
This changelog is utterly useless.

I'll capture my conversation with Don into the commit message and post post V2.

Quoted 5 lines

Thanks,
tglx