[Cluster-devel] [GFS2 PATCH 03/12] gfs2: enhance log_blocks trace point to show log blocks free

[Bob Peterson <rpeterso@redhat.com>]

This patch adds some code to enhance the log_blocks trace point. It
reports the number of free log blocks. This makes the trace point much
more useful, especially for debugging performance problems when we can
tell when the journal gets full and needs to wait for flushes, etc.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
---
 fs/gfs2/trace_gfs2.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/gfs2/trace_gfs2.h b/fs/gfs2/trace_gfs2.h
index e0025258107a..fe140ceef74d 100644
--- a/fs/gfs2/trace_gfs2.h
+++ b/fs/gfs2/trace_gfs2.h
@@ -388,15 +388,17 @@ TRACE_EVENT(gfs2_log_blocks,
 	TP_STRUCT__entry(
 		__field(        dev_t,  dev                     )
 		__field(	int,	blocks			)
+		__field(	int,	blks_free		)
 	),
 
 	TP_fast_assign(
 		__entry->dev		= sdp->sd_vfs->s_dev;
 		__entry->blocks		= blocks;
+		__entry->blks_free	= atomic_read(&sdp->sd_log_blks_free);
 	),
 
-	TP_printk("%u,%u log reserve %d", MAJOR(__entry->dev),
-		  MINOR(__entry->dev), __entry->blocks)
+	TP_printk("%u,%u log reserve %d %d", MAJOR(__entry->dev),
+		  MINOR(__entry->dev), __entry->blocks, __entry->blks_free)
 );
 
 /* Writing back the AIL */
-- 
2.26.2