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. 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 | 41 +++++++++++++++++++++++++++++- kernel/watchdog.c | 65 +++++++++++++++++++++++++++++++--------------- 2 files changed, 84 insertions(+), 22 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
