Laurent Dufour <lduf...@linux.ibm.com> writes: > In some cricunstances it may be interesting to reconfigure the watchdog > from inside the kernel. > > On PowerPC, this may helpful before and after a LPAR migration (LPM) is > initiated, because it implies some latencies, watchdog, and especially NMI > watchdog is expected to be triggered during this operation. Reconfiguring > the watchdog, would prevent it to happen too frequently during LPM. > > The watchdog_mutex is exported to allow some variable to be changed under > its protection and prevent any conflict. > The lockup_detector_reconfigure() function is exported and is expected to > be called under the protection of watchdog_mutex. > > Signed-off-by: Laurent Dufour <lduf...@linux.ibm.com> > --- > include/linux/nmi.h | 3 +++ > kernel/watchdog.c | 6 +++--- > 2 files changed, 6 insertions(+), 3 deletions(-)
Is there a maintainer for kernel/watchdog.c ? There's Wim & Guenter at linux-watchdog@vger but I think that's only for drivers/watchdog? Maybe we should Cc that list anyway? > diff --git a/include/linux/nmi.h b/include/linux/nmi.h > index 750c7f395ca9..84300fb0f90a 100644 > --- a/include/linux/nmi.h > +++ b/include/linux/nmi.h > @@ -122,6 +122,9 @@ int watchdog_nmi_probe(void); > int watchdog_nmi_enable(unsigned int cpu); > void watchdog_nmi_disable(unsigned int cpu); > > +extern struct mutex watchdog_mutex; > +void lockup_detector_reconfigure(void); It would be preferable if we didn't export the mutex. I think you could arrange that by ... Renaming lockup_detector_configure() to __lockup_detector_configure() and then adding a new lockup_detector_configure() that is non-static and takes the lock around __lockup_detector_configure(). cheers
