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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2013-08-09 12:19:29 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2013-09-23 09:16:14 -0700
commit63c4db78e80407976e47bccaa2a4d8251b5a10bc (patch)
tree31b832426eec3bf0e954440afe461b388f84e12d /include/trace
parent591c6d1710cd73824057d08eda302cf2a7cfd18a (diff)
rcu: Add tracing to rcu_gp_kthread()
This commit adds tracing to the rcu_gp_kthread() function in order to help trace down hangs potentially involving this kthread. Reported-by: Clark Williams <williams@redhat.com> Reported-by: Carsten Emde <C.Emde@osadl.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'include/trace')
-rw-r--r--include/trace/events/rcu.h28
1 files changed, 19 insertions, 9 deletions
diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index ee2376cfaab..60077e12093 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -39,15 +39,25 @@ TRACE_EVENT(rcu_utilization,
#if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
/*
- * Tracepoint for grace-period events: starting and ending a grace
- * period ("start" and "end", respectively), a CPU noting the start
- * of a new grace period or the end of an old grace period ("cpustart"
- * and "cpuend", respectively), a CPU passing through a quiescent
- * state ("cpuqs"), a CPU coming online or going offline ("cpuonl"
- * and "cpuofl", respectively), a CPU being kicked for being too
- * long in dyntick-idle mode ("kick"), a CPU accelerating its new
- * callbacks to RCU_NEXT_READY_TAIL ("AccReadyCB"), and a CPU
- * accelerating its new callbacks to RCU_WAIT_TAIL ("AccWaitCB").
+ * Tracepoint for grace-period events. Takes a string identifying the
+ * RCU flavor, the grace-period number, and a string identifying the
+ * grace-period-related event as follows:
+ *
+ * "AccReadyCB": CPU acclerates new callbacks to RCU_NEXT_READY_TAIL.
+ * "AccWaitCB": CPU accelerates new callbacks to RCU_WAIT_TAIL.
+ * "start": Start a grace period.
+ * "cpustart": CPU first notices a grace-period start.
+ * "cpuqs": CPU passes through a quiescent state.
+ * "cpuonl": CPU comes online.
+ * "cpuofl": CPU goes offline.
+ * "reqwait": GP kthread sleeps waiting for grace-period request.
+ * "reqwaitsig": GP kthread awakened by signal from reqwait state.
+ * "fqswait": GP kthread waiting until time to force quiescent states.
+ * "fqsstart": GP kthread starts forcing quiescent states.
+ * "fqsend": GP kthread done forcing quiescent states.
+ * "fqswaitsig": GP kthread awakened by signal from fqswait state.
+ * "end": End a grace period.
+ * "cpuend": CPU first notices a grace-period end.
*/
TRACE_EVENT(rcu_grace_period,