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authorDon Zickus <dzickus@redhat.com>2012-06-13 09:35:48 -0400
committerIngo Molnar <mingo@kernel.org>2012-06-14 12:20:50 +0200
commita70270468234749741c5893ae78e5bb524771402 (patch)
treeaed83d3dc676cc486d43ad30926ac909872a02d8 /kernel/watchdog.c
parent25f42985825dd93f0593efe454e54c2aa13f7830 (diff)
downloadlinux-linaro-stable-a70270468234749741c5893ae78e5bb524771402.tar.gz
watchdog: Quiet down the boot messages
A bunch of bugzillas have complained how noisy the nmi_watchdog is during boot-up especially with its expected failure cases (like virt and bios resource contention). This is my attempt to quiet them down and keep it less confusing for the end user. What I did is print the message for cpu0 and save it for future comparisons. If future cpus have an identical message as cpu0, then don't print the redundant info. However, if a future cpu has a different message, happily print that loudly. Before the change, you would see something like: ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1 CPU0: Intel(R) Core(TM)2 Quad CPU Q9550 @ 2.83GHz stepping 0a Performance Events: PEBS fmt0+, Core2 events, Intel PMU driver. ... version: 2 ... bit width: 40 ... generic registers: 2 ... value mask: 000000ffffffffff ... max period: 000000007fffffff ... fixed-purpose events: 3 ... event mask: 0000000700000003 NMI watchdog enabled, takes one hw-pmu counter. Booting Node 0, Processors #1 NMI watchdog enabled, takes one hw-pmu counter. #2 NMI watchdog enabled, takes one hw-pmu counter. #3 Ok. NMI watchdog enabled, takes one hw-pmu counter. Brought up 4 CPUs Total of 4 processors activated (22607.24 BogoMIPS). After the change, it is simplified to: ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1 CPU0: Intel(R) Core(TM)2 Quad CPU Q9550 @ 2.83GHz stepping 0a Performance Events: PEBS fmt0+, Core2 events, Intel PMU driver. ... version: 2 ... bit width: 40 ... generic registers: 2 ... value mask: 000000ffffffffff ... max period: 000000007fffffff ... fixed-purpose events: 3 ... event mask: 0000000700000003 NMI watchdog: enabled on all CPUs, permanently consumes one hw-PMU counter. Booting Node 0, Processors #1 #2 #3 Ok. Brought up 4 CPUs V2: little changes based on Joe Perches' feedback V3: printk cleanup based on Ingo's feedback; checkpatch fix V4: keep printk as one long line V5: Ingo fix ups Reported-and-tested-by: Nathan Zimmer <nzimmer@sgi.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: nzimmer@sgi.com Cc: joe@perches.com Link: http://lkml.kernel.org/r/1339594548-17227-1-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/watchdog.c')
-rw-r--r--kernel/watchdog.c19
1 files changed, 18 insertions, 1 deletions
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index e5e1d85b8c7c..4b1dfba70f7c 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -372,6 +372,13 @@ static int watchdog(void *unused)
#ifdef CONFIG_HARDLOCKUP_DETECTOR
+/*
+ * People like the simple clean cpu node info on boot.
+ * Reduce the watchdog noise by only printing messages
+ * that are different from what cpu0 displayed.
+ */
+static unsigned long cpu0_err;
+
static int watchdog_nmi_enable(int cpu)
{
struct perf_event_attr *wd_attr;
@@ -390,11 +397,21 @@ static int watchdog_nmi_enable(int cpu)
/* Try to register using hardware perf events */
event = perf_event_create_kernel_counter(wd_attr, cpu, NULL, watchdog_overflow_callback, NULL);
+
+ /* save cpu0 error for future comparision */
+ if (cpu == 0 && IS_ERR(event))
+ cpu0_err = PTR_ERR(event);
+
if (!IS_ERR(event)) {
- pr_info("enabled, takes one hw-pmu counter.\n");
+ /* only print for cpu0 or different than cpu0 */
+ if (cpu == 0 || cpu0_err)
+ pr_info("enabled on all CPUs, permanently consumes one hw-PMU counter.\n");
goto out_save;
}
+ /* skip displaying the same error again */
+ if (cpu > 0 && (PTR_ERR(event) == cpu0_err))
+ return PTR_ERR(event);
/* vary the KERN level based on the returned errno */
if (PTR_ERR(event) == -EOPNOTSUPP)