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  1. 12 May, 2010 4 commits
    • Don Zickus's avatar
      lockup_detector: Remove old softlockup code · 2508ce18
      Don Zickus authored 
      Now that is no longer compiled or used, just remove it.

Also move some of the code wrapped with DETECT_SOFTLOCKUP to the
LOCKUP_DETECTOR wrappers because that is the code that uses it now.
Signed-off-by: default avatarDon Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <1273266711-18706-4-git-send-email-dzickus@redhat.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      2508ce18
    • Don Zickus's avatar
      lockup_detector: Touch_softlockup cleanups and softlockup_tick removal · 332fbdbc
      Don Zickus authored 
      Just some code cleanup to make touch_softlockup clearer and remove the
softlockup_tick function as it is no longer needed.

Also remove the /proc softlockup_thres call as it has been changed to
watchdog_thres.
Signed-off-by: default avatarDon Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <1273266711-18706-3-git-send-email-dzickus@redhat.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      332fbdbc
    • Don Zickus's avatar
      lockup_detector: Combine nmi_watchdog and softlockup detector · 58687acb
      Don Zickus authored 
      The new nmi_watchdog (which uses the perf event subsystem) is very
similar in structure to the softlockup detector.  Using Ingo's
suggestion, I combined the two functionalities into one file:
kernel/watchdog.c.

Now both the nmi_watchdog (or hardlockup detector) and softlockup
detector sit on top of the perf event subsystem, which is run every
60 seconds or so to see if there are any lockups.

To detect hardlockups, cpus not responding to interrupts, I
implemented an hrtimer that runs 5 times for every perf event
overflow event.  If that stops counting on a cpu, then the cpu is
most likely in trouble.

To detect softlockups, tasks not yielding to the scheduler, I used the
previous kthread idea that now gets kicked every time the hrtimer fires.
If the kthread isn't being scheduled neither is anyone else and the
warning is printed to the console.

I tested this on x86_64 and both the softlockup and hardlockup paths
work.

V2:
- cleaned up the Kconfig and softlockup combination
- surrounded hardlockup cases with #ifdef CONFIG_PERF_EVENTS_NMI
- seperated out the softlockup case from perf event subsystem
- re-arranged the enabling/disabling nmi watchdog from proc space
- added cpumasks for hardlockup failure cases
- removed fallback to soft events if no PMU exists for hard events

V3:
- comment cleanups
- drop support for older softlockup code
- per_cpu cleanups
- completely remove software clock base hardlockup detector
- use per_cpu masking on hard/soft lockup detection
- #ifdef cleanups
- rename config option NMI_WATCHDOG to LOCKUP_DETECTOR
- documentation additions

V4:
- documentation fixes
- convert per_cpu to __get_cpu_var
- powerpc compile fixes

V5:
- split apart warn flags for hard and soft lockups

TODO:
- figure out how to make an arch-agnostic clock2cycles call
  (if possible) to feed into perf events as a sample period

[fweisbec: merged conflict patch]
Signed-off-by: default avatarDon Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <1273266711-18706-2-git-send-email-dzickus@redhat.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      58687acb
    • Frederic Weisbecker's avatar
      Merge commit 'v2.6.34-rc7' into perf/nmi · a9aa1d02
      Frederic Weisbecker authored 
      Merge reason: catch up with latest softlockup detector changes.
      a9aa1d02
  3. 10 May, 2010 3 commits
  5. 07 May, 2010 13 commits
  7. 06 May, 2010 20 commits
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