On Tue, Oct 18, 2016 at 12:14:08PM -0700, Babu Moger wrote: > During our testing we noticed that nmi watchdogs in sparc could not be disabled or > enabled dynamically using sysctl/proc interface. Sparc uses its own arch specific > nmi watchdogs. There is a sysctl and proc interface(proc/sys/kernel/nmi_watchdog) > to enable/disable nmi watchdogs. However, that is not working for sparc. There > is no interface to feed this parameter to arch specific nmi watchdogs. > > These patches extend the same sysctl/proc interface to enable or disable > these arch specific nmi watchdogs dynamically. Introduced new functions > arch_watchdog_nmi_enable and arch_watchdog_nmi_disable which can be implemented > in arch specific handlers. > If you think there is a better way to do this. Please advice. > > Tested on sparc. Compile tested on x86. Thanks Babu! Tested-and-Reviewed-by: Don Zickus <dzickus@xxxxxxxxxx> > > v3: > Made one more change per Don Zickus comments. > Moved failure path messages to into generic code inside watchdog_nmi_enable. > Also added matching prints in sparc to warn about the failure. > > v2: > a)Sam Ravnborg's comments about making the definitions visible. > With the new approach we dont need those definitions((NMI_WATCHDOG_ENABLED, > SOFT_WATCHDOG_ENABLED etc..) outside watchdog.c. So no action. > > b) Made changes per Don Zickus comments. > Don, I could not use your patches as is. Reason is sparc does not define > CONFIG_HARDLOCKUP_DETECTOR. So, defining default __weak function did not > work for me. However, I have used your idea to define __weak functions > arch_watchdog_nmi_enable and arch_watchdog_nmi_disable when CONFIG_HARDLOCKUP_DETECTOR > is not defined. I feel this should have very less impact on the races you are > concerned about. Please take a look. Feel free to suggest. > > Patch2 changes: I had to introduce new variable nmi_init_done to synchronize > watchdog thread and kernel init thread. > > v1: > Initial version. Discussion thread here > http://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg1245427.html > > Babu Moger (2): > watchdog: Introduce arch_watchdog_nmi_enable and > arch_watchdog_nmi_disable > sparc: Implement arch_watchdog_nmi_enable and > arch_watchdog_nmi_disable > > arch/sparc/kernel/nmi.c | 44 +++++++++++++++++++++++++++++- > kernel/watchdog.c | 69 +++++++++++++++++++++++++++++++--------------- > 2 files changed, 89 insertions(+), 24 deletions(-) > -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
