Re: [PATCH v2 0/2] Introduce arch specific nmi enable, disable handlers
On Thu, Oct 13, 2016 at 01:38:00PM -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! Looking through the code it seems appropriate with what I suggested. I am running it through my testsuite and things are failing. But it is most likely my system is misconfigured. Give me another day or so to straighten that out. Cheers, Don > > 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@vger.kernel.org/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(-) >
Re: [PATCH v2 0/2] Introduce arch specific nmi enable, disable handlers
On Thu, Oct 13, 2016 at 01:38:00PM -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! Looking through the code it seems appropriate with what I suggested. I am running it through my testsuite and things are failing. But it is most likely my system is misconfigured. Give me another day or so to straighten that out. Cheers, Don > > 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@vger.kernel.org/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(-) >
