This tracks when balance_dirty_pages() tries to wakeup the flusher thread for background writeback (if it was not started already). Suggested-by: Christoph Hellwig <hch@xxxxxxxxxxxxx> Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx> --- fs/fs-writeback.c | 1 + include/trace/events/writeback.h | 1 + 2 files changed, 2 insertions(+) --- linux-next.orig/include/trace/events/writeback.h 2010-11-07 21:54:19.000000000 +0800 +++ linux-next/include/trace/events/writeback.h 2010-11-07 21:56:42.000000000 +0800 @@ -81,6 +81,7 @@ DEFINE_EVENT(writeback_class, name, \ TP_ARGS(bdi)) DEFINE_WRITEBACK_EVENT(writeback_nowork); +DEFINE_WRITEBACK_EVENT(writeback_wake_background); DEFINE_WRITEBACK_EVENT(writeback_wake_thread); DEFINE_WRITEBACK_EVENT(writeback_wake_forker_thread); DEFINE_WRITEBACK_EVENT(writeback_bdi_register); --- linux-next.orig/fs/fs-writeback.c 2010-11-07 21:54:19.000000000 +0800 +++ linux-next/fs/fs-writeback.c 2010-11-07 21:56:42.000000000 +0800 @@ -169,6 +169,7 @@ void bdi_start_background_writeback(stru * We just wake up the flusher thread. It will perform background * writeback as soon as there is no other work to do. */ + trace_writeback_wake_background(bdi); spin_lock_bh(&bdi->wb_lock); bdi_wakeup_flusher(bdi); spin_unlock_bh(&bdi->wb_lock); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>