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SubjectRe: [RFC PATCH 0/4] Clean up watchdog handlers
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On 11/1/2016 8:20 AM, Don Zickus wrote:
> On Mon, Oct 31, 2016 at 04:30:59PM -0500, Babu Moger wrote:
>> On 10/31/2016 4:00 PM, Don Zickus wrote:
>>> On Wed, Oct 26, 2016 at 09:02:19AM -0700, Babu Moger wrote:
>>>> This is an attempt to cleanup watchdog handlers. Right now,
>>>> kernel/watchdog.c implements both softlockup and hardlockup detectors.
>>>> Softlockup code is generic. Hardlockup code is arch specific. Some
>>>> architectures don't use hardlockup detectors. They use their own watchdog
>>>> detectors. To make both these combination work, we have numerous #ifdefs
>>>> in kernel/watchdog.c.
>>>>
>>>> We are trying here to make these handlers independent of each other.
>>>> Also provide an interface for architectures to implement their own
>>>> handlers. watchdog_nmi_enable and watchdog_nmi_disable will be defined
>>>> as weak such that architectures can override its definitions.
>>>>
>>>> Thanks to Don Zickus for his suggestions.
>>>> Here is the previous discussion
>>>> http://www.spinics.net/lists/sparclinux/msg16441.html
>>> Hi Babu,
>>>
>>> I finally got some cycles to poke at this today. Good work. A couple of
>>> suggestions. For bisectability, I am thinking patch2 should be first and
>>> patch1 and patch3 should be combined. Also watchdog_hld.c is going to need
>>> up top:
>>>
>>> #define pr_fmt(fmt) "NMI watchdog: " fmt
>>>
>>> otherwise the error messages miss the header.
>>>
>>> Though I don't think watchdog.c and watchdog_hld.c should have the same
>>> header. A good solution isn't coming to me right now. I will try to run
>>> some tests on this tomorrow.
>> Don, Thanks for the feedback. Let me know if you run into problems with your
>> tests.
> Hi Babu,
>
> My tests passed. I just have to tweak the expected output lines as they
> constantly change. :-(
>
> I am going to play with different config options to see if things break from
> a compile perspective.

Don, Great. Thanks for the update. I had couple of compilation issues
with different config options.

1. drivers/edac/edac_device.o:(.discard+0x0): multiple definition of
`__pcpu_unique_hrtimer_interrupts'
drivers/edac/edac_mc.o:(.discard+0x0): first defined here

This was a problem with uni processor config. Thinking of moving the
definition of hrtimer_interrupts and is_hardlockup
into watchdog.c as softlockup code does most of the work here.

2. kernel/built-in.o: In function `watchdog_overflow_callback':
>> watchdog_hld.c:(.text+0x56940): undefined reference to
`sysctl_hardlockup_all_cpu_backtrace'

Moved this definition to nmi.h.
Will post the v2 version soon with all the comments included.

Thanks
Babu
>
>> I will start working on the comments.
> Great.
>
> Cheers,
> Don
>
>> Thanks
>> Babu
>>
>>> Cheers,
>>> Don
>>>
>>>> Babu Moger (4):
>>>> watchdog: Remove hardlockup handler references
>>>> watchdog: Move shared definitions to nmi.h
>>>> watchdog: Move hardlockup detector in separate file
>>>> sparc: Implement watchdog_nmi_enable and watchdog_nmi_disable
>>>>
>>>> arch/sparc/kernel/nmi.c | 44 ++++++++-
>>>> include/linux/nmi.h | 19 ++++
>>>> kernel/Makefile | 1 +
>>>> kernel/watchdog.c | 276 ++---------------------------------------------
>>>> kernel/watchdog_hld.c | 238 ++++++++++++++++++++++++++++++++++++++++
>>>> 5 files changed, 312 insertions(+), 266 deletions(-)
>>>> create mode 100644 kernel/watchdog_hld.c
>>>>

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