[PATCH 6/6] writeback: convert to relative older_than_this in trace events

[Wu Fengguang]

This is a format change that could break established scripts.

But hopefully it's more human friendly to show the relative values like
"30000" (30s old) or "0" (all fresh ones) than long absolute jiffy
numbers.

Note that the initial 30000 or 0 may increase over time as they are now
relative numbers.

CC: Jan Kara <jack@xxxxxxx>
CC: Dave Chinner <david@xxxxxxxxxxxxx> 
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
---
 include/trace/events/writeback.h |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

--- linux-next.orig/include/trace/events/writeback.h	2011-05-04 16:09:59.000000000 +0800
+++ linux-next/include/trace/events/writeback.h	2011-05-04 16:10:57.000000000 +0800
@@ -115,7 +115,7 @@ DECLARE_EVENT_CLASS(wbc_class,
 		__field(int, for_reclaim)
 		__field(int, range_cyclic)
 		__field(int, more_io)
-		__field(unsigned long, older_than_this)
+		__field(int, older)
 		__field(long, range_start)
 		__field(long, range_end)
 	),
@@ -130,14 +130,15 @@ DECLARE_EVENT_CLASS(wbc_class,
 		__entry->for_reclaim	= wbc->for_reclaim;
 		__entry->range_cyclic	= wbc->range_cyclic;
 		__entry->more_io	= wbc->more_io;
-		__entry->older_than_this = wbc->older_than_this ?
-						*wbc->older_than_this : 0;
+		__entry->older		= wbc->older_than_this ?
+				(jiffies - *wbc->older_than_this) * 1000 / HZ
+				: -1;
 		__entry->range_start	= (long)wbc->range_start;
 		__entry->range_end	= (long)wbc->range_end;
 	),
 
 	TP_printk("bdi %s: towrt=%ld skip=%ld mode=%d kupd=%d "
-		"bgrd=%d reclm=%d cyclic=%d more=%d older=0x%lx "
+		"bgrd=%d reclm=%d cyclic=%d more=%d older=%d "
 		"start=0x%lx end=0x%lx",
 		__entry->name,
 		__entry->nr_to_write,
@@ -148,7 +149,7 @@ DECLARE_EVENT_CLASS(wbc_class,
 		__entry->for_reclaim,
 		__entry->range_cyclic,
 		__entry->more_io,
-		__entry->older_than_this,
+		__entry->older,
 		__entry->range_start,
 		__entry->range_end)
 )


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/