On Mon, Sep 28, 2015 at 10:44:07PM +0200, Ulrich Obergfell wrote: > The original watchdog_park_threads() function that was introduced by > commit 81a4beef91ba4a9e8ad6054ca9933dff7e25ff28 takes a very simple > approach to handle errors returned by kthread_park(): It attempts to > roll back all watchdog threads to the unparked state. However, this > may be undesired behaviour from the perspective of the caller which > may want to handle errors as appropriate in its specific context. > Currently, there are two possible call chains:
I spent a little time cleaning up some of my test scripts for this code. Things seem to work well. Hardlockups and softlockups work along with enabling/disabling the various lockup knobs. Acked-by: Don Zickus <[email protected]> > > - watchdog suspend/resume interface > > lockup_detector_suspend > watchdog_park_threads > > - write to parameters in /proc/sys/kernel > > proc_watchdog_update > watchdog_enable_all_cpus > update_watchdog_all_cpus > watchdog_park_threads > > Instead of 'blindly' attempting to unpark the watchdog threads if a > kthread_park() call fails, the new approach is to disable the lockup > detectors in the above call chains. Failure becomes visible to the > user as follows: > > - error messages from lockup_detector_suspend() > or watchdog_enable_all_cpus() > > - the state that can be read from /proc/sys/kernel/watchdog_enabled > > - the 'write' system call in the latter call chain returns an error > > Ulrich Obergfell (5): > watchdog: fix error handling in proc_watchdog_thresh() > watchdog: move watchdog_disable_all_cpus() outside of ifdef > watchdog: implement error handling in update_watchdog_all_cpus() and > callers > watchdog: implement error handling in lockup_detector_suspend() > watchdog: do not unpark threads in watchdog_park_threads() on error > > kernel/watchdog.c | 60 > +++++++++++++++++++++++++++++++++++++++---------------- > 1 file changed, 43 insertions(+), 17 deletions(-) > > -- > 1.7.11.7 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
