• Ulrich Obergfell's avatar
    watchdog: enable the new user interface of the watchdog mechanism · 195daf66
    Ulrich Obergfell authored
    With the current user interface of the watchdog mechanism it is only
    possible to disable or enable both lockup detectors at the same time.
    This series introduces new kernel parameters and changes the semantics of
    some existing kernel parameters, so that the hard lockup detector and the
    soft lockup detector can be disabled or enabled individually.  With this
    series applied, the user interface is as follows.
    
    - parameters in /proc/sys/kernel
    
      . soft_watchdog
        This is a new parameter to control and examine the run state of
        the soft lockup detector.
    
      . nmi_watchdog
        The semantics of this parameter have changed. It can now be used
        to control and examine the run state of the hard lockup detector.
    
      . watchdog
        This parameter is still available to control the run state of both
        lockup detectors at the same time. If this parameter is examined,
        it shows the logical OR of soft_watchdog and nmi_watchdog.
    
      . watchdog_thresh
        The semantics of this parameter are not affected by the patch.
    
    - kernel command line parameters
    
      . nosoftlockup
        The semantics of this parameter have changed. It can now be used
        to disable the soft lockup detector at boot time.
    
      . nmi_watchdog=0 or nmi_watchdog=1
        Disable or enable the hard lockup detector at boot time. The patch
        introduces '=1' as a new option.
    
      . nowatchdog
        The semantics of this parameter are not affected by the patch. It
        is still available to disable both lockup detectors at boot time.
    
    Also, remove the proc_dowatchdog() function which is no longer needed.
    
    [dzickus@redhat.com: wrote changelog]
    [dzickus@redhat.com: update documentation for kernel params and sysctl]
    Signed-off-by: default avatarUlrich Obergfell <uobergfe@redhat.com>
    Signed-off-by: default avatarDon Zickus <dzickus@redhat.com>
    Cc: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    195daf66
nmi.h 2.29 KB