The patch titled
Subject: softlockup-make-detector-be-aware-of-task-switch-of-processes-hogging-cpu-fix
has been added to the -mm tree. Its filename is
softlockup-make-detector-be-aware-of-task-switch-of-processes-hogging-cpu-fix.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/softlockup-make-detector-be-aware-of-task-switch-of-processes-hogging-cpu-fix.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/softlockup-make-detector-be-aware-of-task-switch-of-processes-hogging-cpu-fix.patch
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------------------------------------------------------
From: Don Zickus <dzickus@xxxxxxxxxx>
Subject: softlockup-make-detector-be-aware-of-task-switch-of-processes-hogging-cpu-fix
update comment
Cc: Don Zickus <dzickus@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: chai wen <chaiw.fnst@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/watchdog.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff -puN kernel/watchdog.c~softlockup-make-detector-be-aware-of-task-switch-of-processes-hogging-cpu-fix kernel/watchdog.c
--- a/kernel/watchdog.c~softlockup-make-detector-be-aware-of-task-switch-of-processes-hogging-cpu-fix
+++ a/kernel/watchdog.c
@@ -336,10 +336,12 @@ static enum hrtimer_restart watchdog_tim
/* only warn once */
if (__this_cpu_read(soft_watchdog_warn) == true) {
/*
- * Handle the case where multiple processes are
- * causing softlockups but the duration is small
- * enough, the softlockup detector can not reset
- * itself in time. Use task pointers to detect this.
+ * When multiple processes are causing softlockups the
+ * softlockup detector only warns on the first one
+ * because the code relies on a full quiet cycle to
+ * re-arm. The second process prevents the quiet cycle
+ * and never gets reported. Use task pointers to detect
+ * this.
*/
if (__this_cpu_read(softlockup_task_ptr_saved) !=
current) {
_
Patches currently in -mm which might be from dzickus@xxxxxxxxxx are
softlockup-make-detector-be-aware-of-task-switch-of-processes-hogging-cpu.patch
softlockup-make-detector-be-aware-of-task-switch-of-processes-hogging-cpu-fix.patch
linux-next.patch
watchdog-control-hard-lockup-detection-default.patch
watchdog-control-hard-lockup-detection-default-fix.patch
watchdog-control-hard-lockup-detection-default-fix-2.patch
kvm-ensure-hard-lockup-detection-is-disabled-by-default.patch
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