xfs: rework the perag trace points to be perag centric

So that they all output the same information in the traces to make
debugging refcount issues easier.

This means that all the lookup/drop functions no longer need to use
the full memory barrier atomic operations (atomic*_return()) so
will have less overhead when tracing is off. The set/clear tag
tracepoints no longer abuse the reference count to pass the tag -
the tag being cleared is obvious from the _RET_IP_ that is recorded
in the trace point.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

3 files changed, 22 insertions, 28 deletions

diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
index 46e25c682bf4..7cff61875340 100644
--- a/fs/xfs/libxfs/xfs_ag.c
+++ b/fs/xfs/libxfs/xfs_ag.c
@@ -44,16 +44,15 @@ xfs_perag_get(
 	xfs_agnumber_t		agno)
 {
 	struct xfs_perag	*pag;
-	int			ref = 0;
 
 	rcu_read_lock();
 	pag = radix_tree_lookup(&mp->m_perag_tree, agno);
 	if (pag) {
+		trace_xfs_perag_get(pag, _RET_IP_);
 		ASSERT(atomic_read(&pag->pag_ref) >= 0);
-		ref = atomic_inc_return(&pag->pag_ref);
+		atomic_inc(&pag->pag_ref);
 	}
 	rcu_read_unlock();
-	trace_xfs_perag_get(mp, agno, ref, _RET_IP_);
 	return pag;
 }
 
@@ -68,7 +67,6 @@ xfs_perag_get_tag(
 {
 	struct xfs_perag	*pag;
 	int			found;
-	int			ref;
 
 	rcu_read_lock();
 	found = radix_tree_gang_lookup_tag(&mp->m_perag_tree,
@@ -77,9 +75,9 @@ xfs_perag_get_tag(
 		rcu_read_unlock();
 		return NULL;
 	}
-	ref = atomic_inc_return(&pag->pag_ref);
+	trace_xfs_perag_get_tag(pag, _RET_IP_);
+	atomic_inc(&pag->pag_ref);
 	rcu_read_unlock();
-	trace_xfs_perag_get_tag(mp, pag->pag_agno, ref, _RET_IP_);
 	return pag;
 }
 
@@ -87,11 +85,9 @@ void
 xfs_perag_put(
 	struct xfs_perag	*pag)
 {
-	int	ref;
-
+	trace_xfs_perag_put(pag, _RET_IP_);
 	ASSERT(atomic_read(&pag->pag_ref) > 0);
-	ref = atomic_dec_return(&pag->pag_ref);
-	trace_xfs_perag_put(pag->pag_mount, pag->pag_agno, ref, _RET_IP_);
+	atomic_dec(&pag->pag_ref);
 }
 
 /*
@@ -110,8 +106,7 @@ xfs_perag_grab(
 	rcu_read_lock();
 	pag = radix_tree_lookup(&mp->m_perag_tree, agno);
 	if (pag) {
-		trace_xfs_perag_grab(mp, pag->pag_agno,
-				atomic_read(&pag->pag_active_ref), _RET_IP_);
+		trace_xfs_perag_grab(pag, _RET_IP_);
 		if (!atomic_inc_not_zero(&pag->pag_active_ref))
 			pag = NULL;
 	}
@@ -138,8 +133,7 @@ xfs_perag_grab_tag(
 		rcu_read_unlock();
 		return NULL;
 	}
-	trace_xfs_perag_grab_tag(mp, pag->pag_agno,
-			atomic_read(&pag->pag_active_ref), _RET_IP_);
+	trace_xfs_perag_grab_tag(pag, _RET_IP_);
 	if (!atomic_inc_not_zero(&pag->pag_active_ref))
 		pag = NULL;
 	rcu_read_unlock();
@@ -150,8 +144,7 @@ void
 xfs_perag_rele(
 	struct xfs_perag	*pag)
 {
-	trace_xfs_perag_rele(pag->pag_mount, pag->pag_agno,
-			atomic_read(&pag->pag_active_ref), _RET_IP_);
+	trace_xfs_perag_rele(pag, _RET_IP_);
 	if (atomic_dec_and_test(&pag->pag_active_ref))
 		wake_up(&pag->pag_active_wq);
 }
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 0f4a014dded3..8b2823d85a68 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -255,7 +255,7 @@ xfs_perag_set_inode_tag(
 		break;
 	}
 
-	trace_xfs_perag_set_inode_tag(mp, pag->pag_agno, tag, _RET_IP_);
+	trace_xfs_perag_set_inode_tag(pag, _RET_IP_);
 }
 
 /* Clear a tag on both the AG incore inode tree and the AG radix tree. */
@@ -289,7 +289,7 @@ xfs_perag_clear_inode_tag(
 	radix_tree_tag_clear(&mp->m_perag_tree, pag->pag_agno, tag);
 	spin_unlock(&mp->m_perag_lock);
 
-	trace_xfs_perag_clear_inode_tag(mp, pag->pag_agno, tag, _RET_IP_);
+	trace_xfs_perag_clear_inode_tag(pag, _RET_IP_);
 }
 
 /*
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index eb5e49d44f13..1d99c30f66f0 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -159,33 +159,34 @@ TRACE_EVENT(xlog_intent_recovery_failed,
 );
 
 DECLARE_EVENT_CLASS(xfs_perag_class,
-	TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, int refcount,
-		 unsigned long caller_ip),
-	TP_ARGS(mp, agno, refcount, caller_ip),
+	TP_PROTO(struct xfs_perag *pag, unsigned long caller_ip),
+	TP_ARGS(pag, caller_ip),
 	TP_STRUCT__entry(
 		__field(dev_t, dev)
 		__field(xfs_agnumber_t, agno)
 		__field(int, refcount)
+		__field(int, active_refcount)
 		__field(unsigned long, caller_ip)
 	),
 	TP_fast_assign(
-		__entry->dev = mp->m_super->s_dev;
-		__entry->agno = agno;
-		__entry->refcount = refcount;
+		__entry->dev = pag->pag_mount->m_super->s_dev;
+		__entry->agno = pag->pag_agno;
+		__entry->refcount = atomic_read(&pag->pag_ref);
+		__entry->active_refcount = atomic_read(&pag->pag_active_ref);
 		__entry->caller_ip = caller_ip;
 	),
-	TP_printk("dev %d:%d agno 0x%x refcount %d caller %pS",
+	TP_printk("dev %d:%d agno 0x%x passive refs %d active refs %d caller %pS",
 		  MAJOR(__entry->dev), MINOR(__entry->dev),
 		  __entry->agno,
 		  __entry->refcount,
+		  __entry->active_refcount,
 		  (char *)__entry->caller_ip)
 );
 
 #define DEFINE_PERAG_REF_EVENT(name)	\
 DEFINE_EVENT(xfs_perag_class, name,	\
-	TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, int refcount,	\
-		 unsigned long caller_ip),					\
-	TP_ARGS(mp, agno, refcount, caller_ip))
+	TP_PROTO(struct xfs_perag *pag, unsigned long caller_ip), \
+	TP_ARGS(pag, caller_ip))
 DEFINE_PERAG_REF_EVENT(xfs_perag_get);
 DEFINE_PERAG_REF_EVENT(xfs_perag_get_tag);
 DEFINE_PERAG_REF_EVENT(xfs_perag_put);