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authorArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2010-07-25 14:29:24 +0300
committerJens Axboe <jaxboe@fusionio.com>2010-08-07 18:53:56 +0200
commit603320239fb436f175c8b6bfa43d5023c47a6dc2 (patch)
treeefe1e78de6c2b8029cdcdcad2e98e3ef6c017900
parentb5048a6cb5455a16bdff26a4c5ae9534f070d94c (diff)
downloadlinux-603320239fb436f175c8b6bfa43d5023c47a6dc2.tar.bz2
writeback: add new tracepoints
Add 2 new trace points to the periodic write-back wake up case, just like we do in the 'bdi_queue_work()' function. Namely, introduce: 1. trace_writeback_wake_thread(bdi) 2. trace_writeback_wake_forker_thread(bdi) The first event is triggered every time we wake up a bdi thread to start periodic background write-out. The second event is triggered only when the bdi thread does not exist and should be created by the forker thread. This patch was suggested by Dave Chinner and Christoph Hellwig. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
-rw-r--r--include/trace/events/writeback.h2
-rw-r--r--mm/backing-dev.c2
2 files changed, 4 insertions, 0 deletions
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index 84ab72df953c..f345f66ae9d1 100644
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -81,6 +81,8 @@ DEFINE_EVENT(writeback_class, name, \
TP_ARGS(bdi))
DEFINE_WRITEBACK_EVENT(writeback_nowork);
+DEFINE_WRITEBACK_EVENT(writeback_wake_thread);
+DEFINE_WRITEBACK_EVENT(writeback_wake_forker_thread);
DEFINE_WRITEBACK_EVENT(writeback_bdi_register);
DEFINE_WRITEBACK_EVENT(writeback_bdi_unregister);
DEFINE_WRITEBACK_EVENT(writeback_thread_start);
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 99890831d557..9008c4e207f6 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -310,6 +310,7 @@ static void wakeup_timer_fn(unsigned long data)
spin_lock_bh(&bdi->wb_lock);
if (bdi->wb.task) {
+ trace_writeback_wake_thread(bdi);
wake_up_process(bdi->wb.task);
} else {
/*
@@ -317,6 +318,7 @@ static void wakeup_timer_fn(unsigned long data)
* In this case we have to wake-up the forker thread which
* should create and run the bdi thread.
*/
+ trace_writeback_wake_forker_thread(bdi);
wake_up_process(default_backing_dev_info.wb.task);
}
spin_unlock_bh(&bdi->wb_lock);