block: make unplug timer trace event correspond to the schedule() unplug

It's a pretty close match to what we had before - the timer triggering
would mean that nobody unplugged the plug in due time, in the new
scheme this matches very closely what the schedule() unplug now is.
It's essentially the difference between an explicit unplug (IO unplug)
or an implicit unplug (timer unplug, we scheduled with pending IO
queued).

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 12 insertions, 6 deletions

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 3e3970d53d14..6957aa298dfa 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -850,16 +850,21 @@ static void blk_add_trace_plug(void *ignore, struct request_queue *q)
                 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
 }
 
-static void blk_add_trace_unplug_io(void *ignore, struct request_queue *q,
-                                    unsigned int depth)
+static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
+                                    unsigned int depth, bool explicit)
 {
         struct blk_trace *bt = q->blk_trace;
 
         if (bt) {
                 __be64 rpdu = cpu_to_be64(depth);
+                u32 what;
 
-                __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
-                                sizeof(rpdu), &rpdu);
+                if (explicit)
+                        what = BLK_TA_UNPLUG_IO;
+                else
+                        what = BLK_TA_UNPLUG_TIMER;
+
+                __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
         }
 }
 
@@ -1002,7 +1007,7 @@ static void blk_register_tracepoints(void)
         WARN_ON(ret);
         ret = register_trace_block_plug(blk_add_trace_plug, NULL);
         WARN_ON(ret);
-        ret = register_trace_block_unplug_io(blk_add_trace_unplug_io, NULL);
+        ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
         WARN_ON(ret);
         ret = register_trace_block_split(blk_add_trace_split, NULL);
         WARN_ON(ret);
@@ -1017,7 +1022,7 @@ static void blk_unregister_tracepoints(void)
         unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
         unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL);
         unregister_trace_block_split(blk_add_trace_split, NULL);
-        unregister_trace_block_unplug_io(blk_add_trace_unplug_io, NULL);
+        unregister_trace_block_unplug(blk_add_trace_unplug, NULL);
         unregister_trace_block_plug(blk_add_trace_plug, NULL);
         unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
         unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
@@ -1332,6 +1337,7 @@ static const struct {
         [__BLK_TA_COMPLETE]     = {{  "C", "complete" },   blk_log_with_error },
         [__BLK_TA_PLUG]         = {{  "P", "plug" },       blk_log_plug },
         [__BLK_TA_UNPLUG_IO]    = {{  "U", "unplug_io" },  blk_log_unplug },
+        [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
         [__BLK_TA_INSERT]       = {{  "I", "insert" },     blk_log_generic },
         [__BLK_TA_SPLIT]        = {{  "X", "split" },      blk_log_split },
         [__BLK_TA_BOUNCE]       = {{  "B", "bounce" },     blk_log_generic },