Re: [PATCH v2] watchdog: Quiet down the boot messages

[Andrew Morton <akpm@linux-foundation.org>]

On Fri,  8 Jun 2012 17:03:09 -0400
Don Zickus <dzickus@redhat.com> wrote:

> 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, takes one hw-pmu counter.
>     Booting Node   0, Processors  #1 #2 #3 Ok.
>     Brought up 4 CPUs

What is the behaviour of this change at suspend/resume time?

> +		if (cpu ==0 || cpu0_err)

Please use checkpatch.  It's free!