[PATCH 1/2] tracing/events: block: track and print if unplug was explicit or schedule

From: Steffen Maier
Date: Fri Apr 13 2018 - 09:08:09 EST


Just like blktrace distinguishes explicit and schedule by means of
BLK_TA_UNPLUG_IO and BLK_TA_UNPLUG_TIMER, actually make use of the
existing argument "explicit" to distinguish the two cases in the one
common tracepoint block_unplug.

Complements v2.6.39 commit 49cac01e1fa7 ("block: make unplug timer trace
event correspond to the schedule() unplug") and commit d9c978331790
("block: remove block_unplug_timer() trace point").

Signed-off-by: Steffen Maier <maier@xxxxxxxxxxxxx>
---
include/trace/events/block.h | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index 81b43f5bdf23..a13613d27cee 100644
--- a/include/trace/events/block.h
+++ b/include/trace/events/block.h
@@ -470,6 +470,11 @@ TRACE_EVENT(block_plug,
TP_printk("[%s]", __entry->comm)
);

+#define show_block_unplug_explicit(val) \
+ __print_symbolic(val, \
+ {false, "schedule"}, \
+ {true, "explicit"})
+
DECLARE_EVENT_CLASS(block_unplug,

TP_PROTO(struct request_queue *q, unsigned int depth, bool explicit),
@@ -478,15 +483,18 @@ DECLARE_EVENT_CLASS(block_unplug,

TP_STRUCT__entry(
__field( int, nr_rq )
+ __field( bool, explicit )
__array( char, comm, TASK_COMM_LEN )
),

TP_fast_assign(
__entry->nr_rq = depth;
+ __entry->explicit = explicit;
memcpy(__entry->comm, current->comm, TASK_COMM_LEN);
),

- TP_printk("[%s] %d", __entry->comm, __entry->nr_rq)
+ TP_printk("[%s] %d %s", __entry->comm, __entry->nr_rq,
+ show_block_unplug_explicit(__entry->explicit))
);

/**
--
2.13.5