Re: [PATCH v2 0/3] Clean up watchdog handlers

[Babu Moger]

On 11/4/2016 11:25 AM, Don Zickus wrote:
> On Tue, Nov 01, 2016 at 02:13:43PM -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 are our previous discussions
> > http://www.spinics.net/lists/sparclinux/msg16543.html
> > http://www.spinics.net/lists/sparclinux/msg16441.html
> Hi Babu,
>
> Thanks for the patches.  It passes my panic/reboot testing.  The patches
> look good for now.  Though this change has me thinking about other cleanup
> changes I can make on top of this.  But I am going to hold off for now until
> we are sure nothing really broke.  As this should be a straight forward
> split.
>
> The only odd thing for me is I am having trouble disabling
> CONFIG_HARDLOCKUP_DETECTOR.  For some reason def_bool y, is forcing the
> option on despite my repeated attempts to disable it.  I had to rename the
> option to do some test compiling and verify it doesn't regress when
> disabled.  Probably my environment..

  Don, You are welcome. Thanks for your feedback to resolve this.

> Thanks for the work Babu!
>
> Acked-by: Don Zickus <dzickus@xxxxxxxxxx>
>
>
> > v2:
> >    Addressed few comments from Don Zickus.
> >    1. Took care of bisectability issue. Previous patch2 is patch1 now.
> >       Combined patch 1 and 3. Patch 4 is now patch 3.
> >    2. Added pr_fmt back in watchdog_hld.c
> >    3. Tweaked the file headers for watchdog.c and watchdog_hld.c.
> >
> >    4. Took care of couple of config compile issues.
> >
> >     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. Moved the definition of hrtimer_interrupts and
> >     is_hardlockup into watchdog.c as softlockup code does most of the work here.
> >     is_hardlockup kind of generic most part.
> >
> >     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.
> >
> > v1:
> >    Initial version
> > Babu Moger (3):
> >    watchdog: Move shared definitions to nmi.h
> >    watchdog: Move hardlockup detector to separate file
> >    sparc: Implement watchdog_nmi_enable and watchdog_nmi_disable
> >
> >   arch/sparc/kernel/nmi.c |   44 ++++++++-
> >   include/linux/nmi.h     |   24 ++++
> >   kernel/Makefile         |    1 +
> >   kernel/watchdog.c       |  270 +++--------------------------------------------
> >   kernel/watchdog_hld.c   |  227 +++++++++++++++++++++++++++++++++++++++
> >   5 files changed, 310 insertions(+), 256 deletions(-)
> >   create mode 100644 kernel/watchdog_hld.c