[Cluster-devel] [GFS2 PATCH 08/11] gfs2: Add caller info to log_blocks trace point

[Bob Peterson <rpeterso@redhat.com>]

The log_blocks kernel trace point becomes much more useful if we know
from whence the call was made. This patch adds caller info to the trace
point.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
---
 fs/gfs2/log.c        | 12 ++++++------
 fs/gfs2/ops_fstype.c |  2 +-
 fs/gfs2/trace_gfs2.h | 20 ++++++++++++++++----
 3 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index a58333e3980d..665e287bf4f1 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -396,7 +396,7 @@ void gfs2_log_release(struct gfs2_sbd *sdp, unsigned int blks)
 {
 
 	atomic_add(blks, &sdp->sd_log_blks_free);
-	trace_gfs2_log_blocks(sdp, blks);
+	trace_gfs2_log_blocks(sdp, blks, 0);
 	gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
 				  sdp->sd_jdesc->jd_blocks);
 	up_read(&sdp->sd_log_flush_lock);
@@ -457,7 +457,7 @@ int gfs2_log_reserve(struct gfs2_sbd *sdp, unsigned int blks)
 		goto retry;
 	}
 	atomic_sub(blks, &sdp->sd_log_blks_needed);
-	trace_gfs2_log_blocks(sdp, -blks);
+	trace_gfs2_log_blocks(sdp, -blks, 1);
 
 	/*
 	 * If we waited, then so might others, wake them up _after_ we get
@@ -576,7 +576,7 @@ static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail)
 	ail2_empty(sdp, new_tail);
 
 	atomic_add(dist, &sdp->sd_log_blks_free);
-	trace_gfs2_log_blocks(sdp, dist);
+	trace_gfs2_log_blocks(sdp, dist, 2);
 	gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
 			     sdp->sd_jdesc->jd_blocks);
 
@@ -966,7 +966,7 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags)
 		log_write_header(sdp, flags);
 	} else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle){
 		atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved buffer */
-		trace_gfs2_log_blocks(sdp, -1);
+		trace_gfs2_log_blocks(sdp, -1, 3);
 		log_write_header(sdp, flags);
 	}
 	if (gfs2_withdrawn(sdp))
@@ -992,7 +992,7 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl, u32 flags)
 			if (gfs2_withdrawn(sdp))
 				goto out;
 			atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved buffer */
-			trace_gfs2_log_blocks(sdp, -1);
+			trace_gfs2_log_blocks(sdp, -1, 4);
 			log_write_header(sdp, flags);
 			sdp->sd_log_head = sdp->sd_log_flush_head;
 		}
@@ -1075,7 +1075,7 @@ static void log_refund(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
 	gfs2_assert_withdraw(sdp, maxres >= reserved);
 	unused = maxres - reserved;
 	atomic_add(unused, &sdp->sd_log_blks_free);
-	trace_gfs2_log_blocks(sdp, unused);
+	trace_gfs2_log_blocks(sdp, unused, 5);
 	gfs2_assert_withdraw(sdp, atomic_read(&sdp->sd_log_blks_free) <=
 			     sdp->sd_jdesc->jd_blocks);
 	sdp->sd_log_blks_reserved = reserved;
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 6d18d2c91add..b2538eea3e5e 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -688,7 +688,7 @@ static int init_journal(struct gfs2_sbd *sdp, int undo)
 		/* Map the extents for this journal's blocks */
 		gfs2_map_journal_extents(sdp, sdp->sd_jdesc);
 	}
-	trace_gfs2_log_blocks(sdp, atomic_read(&sdp->sd_log_blks_free));
+	trace_gfs2_log_blocks(sdp, atomic_read(&sdp->sd_log_blks_free), 6);
 
 	if (sdp->sd_lockstruct.ls_first) {
 		unsigned int x;
diff --git a/fs/gfs2/trace_gfs2.h b/fs/gfs2/trace_gfs2.h
index e0025258107a..1c4aa666e7e0 100644
--- a/fs/gfs2/trace_gfs2.h
+++ b/fs/gfs2/trace_gfs2.h
@@ -45,6 +45,15 @@
 					 { 2, "ins " },	\
 					 { 3, "clm " })
 
+#define lbcaller(x) __print_symbolic(x, \
+	{ 0, "gfs2_log_release" }, \
+	{ 1, "gfs2_log_reserve" }, \
+	{ 2, "log_pull_tail" },	   \
+	{ 3, "gfs2_log_flush" }, \
+	{ 4, "gfs2_log_flush2" }, \
+	{ 5, "log_refund" }, \
+	{ 6, "init_journal" })
+
 #define show_glock_flags(flags) __print_flags(flags, "",	\
 	{(1UL << GLF_LOCK),			"l" },		\
 	{(1UL << GLF_DEMOTE),			"D" },		\
@@ -381,22 +390,25 @@ TRACE_EVENT(gfs2_log_flush,
 /* Reserving/releasing blocks in the log */
 TRACE_EVENT(gfs2_log_blocks,
 
-	TP_PROTO(const struct gfs2_sbd *sdp, int blocks),
+	TP_PROTO(const struct gfs2_sbd *sdp, int blocks, int caller),
 
-	TP_ARGS(sdp, blocks),
+	TP_ARGS(sdp, blocks, caller),
 
 	TP_STRUCT__entry(
 		__field(        dev_t,  dev                     )
 		__field(	int,	blocks			)
+		__field(	int,	caller			)
 	),
 
 	TP_fast_assign(
 		__entry->dev		= sdp->sd_vfs->s_dev;
 		__entry->blocks		= blocks;
+		__entry->caller		= caller;
 	),
 
-	TP_printk("%u,%u log reserve %d", MAJOR(__entry->dev),
-		  MINOR(__entry->dev), __entry->blocks)
+	TP_printk("%u,%u log reserve %d %s", MAJOR(__entry->dev),
+		  MINOR(__entry->dev), __entry->blocks,
+		  lbcaller(__entry->caller))
 );
 
 /* Writing back the AIL */
-- 
2.26.2