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| author | Sangmoon Kim <sangmoon.kim@samsung.com> | 2021-03-02 12:55:15 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-03-15 21:53:24 +0100 |
| commit | 565cfb9e64dac1aadf7e2130fcda19a1c018df66 (patch) | |
| tree | 07a85851e876c0cb1b270e51f6677c5fa9e44180 /include/trace/events/rcu.h | |
| parent | rcu: Add explicit barrier() to __rcu_read_unlock() (diff) | |
| download | linux-565cfb9e64dac1aadf7e2130fcda19a1c018df66.tar.xz linux-565cfb9e64dac1aadf7e2130fcda19a1c018df66.zip | |
rcu/tree: Add a trace event for RCU CPU stall warnings
This commit adds a trace event which allows tracing the beginnings of RCU
CPU stall warnings on systems where sysctl_panic_on_rcu_stall is disabled.
The first parameter is the name of RCU flavor like other trace events.
The second parameter indicates whether this is a stall of an expedited
grace period, a self-detected stall of a normal grace period, or a stall
of a normal grace period detected by some CPU other than the one that
is stalled.
RCU CPU stall warnings are often caused by external-to-RCU issues,
for example, in interrupt handling or task scheduling. Therefore,
this event uses TRACE_EVENT, not TRACE_EVENT_RCU, to avoid requiring
those interested in tracing RCU CPU stalls to rebuild their kernels
with CONFIG_RCU_TRACE=y.
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Sangmoon Kim <sangmoon.kim@samsung.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'include/trace/events/rcu.h')
| -rw-r--r-- | include/trace/events/rcu.h | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index 5fc29400e1a2..c7711e9b6900 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -432,6 +432,34 @@ TRACE_EVENT_RCU(rcu_fqs, __entry->cpu, __entry->qsevent) ); +/* + * Tracepoint for RCU stall events. Takes a string identifying the RCU flavor + * and a string identifying which function detected the RCU stall as follows: + * + * "StallDetected": Scheduler-tick detects other CPU's stalls. + * "SelfDetected": Scheduler-tick detects a current CPU's stall. + * "ExpeditedStall": Expedited grace period detects stalls. + */ +TRACE_EVENT(rcu_stall_warning, + + TP_PROTO(const char *rcuname, const char *msg), + + TP_ARGS(rcuname, msg), + + TP_STRUCT__entry( + __field(const char *, rcuname) + __field(const char *, msg) + ), + + TP_fast_assign( + __entry->rcuname = rcuname; + __entry->msg = msg; + ), + + TP_printk("%s %s", + __entry->rcuname, __entry->msg) +); + #endif /* #if defined(CONFIG_TREE_RCU) */ /* |