xfs: rework the perag trace points to be perag centric

Source kernel commit: 368e2d09b41caa5b44a61bb518c362f46d6d615c

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>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

2 files changed, 12 insertions, 24 deletions

diff --git a/include/xfs_trace.h b/include/xfs_trace.h
index 65c2a225ec..c9398c4d89 100644
--- a/include/xfs_trace.h
+++ b/include/xfs_trace.h
@@ -181,11 +181,11 @@
 
 /* set c = c to avoid unused var warnings */
 #define trace_xfs_write_extent(a,b,c,d)	((c) = (c))
-#define trace_xfs_perag_get(a,b,c,d)	((c) = (c))
-#define trace_xfs_perag_get_tag(a,b,c,d) ((c) = (c))
+#define trace_xfs_perag_get(c,d)		((c) = (c))
+#define trace_xfs_perag_get_tag(c,d)		((c) = (c))
 #define trace_xfs_perag_grab(...)		((void) 0)
 #define trace_xfs_perag_grab_tag(...)		((void) 0)
-#define trace_xfs_perag_put(a,b,c,d)	((c) = (c))
+#define trace_xfs_perag_put(c,d)		((c) = (c))
 #define trace_xfs_perag_rele(...)		((void) 0)
 
 #define trace_xfs_trans_alloc(a,b)		((void) 0)
@@ -326,9 +326,4 @@
 
 #define trace_xfs_fs_mark_healthy(a,b)		((void) 0)
 
-/* set c = c to avoid unused var warnings */
-#define trace_xfs_perag_get(a,b,c,d)		((c) = (c))
-#define trace_xfs_perag_get_tag(a,b,c,d)	((c) = (c))
-#define trace_xfs_perag_put(a,b,c,d)		((c) = (c))
-
 #endif /* __TRACE_H__ */
diff --git a/libxfs/xfs_ag.c b/libxfs/xfs_ag.c
index 19a5e5dc84..1b0e03502d 100644
--- a/libxfs/xfs_ag.c
+++ b/libxfs/xfs_ag.c
@@ -42,16 +42,15 @@ 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;
 }
 
@@ -66,7 +65,6 @@ 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,
@@ -75,9 +73,9 @@ 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;
 }
 
@@ -85,11 +83,9 @@ 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);
 }
 
 /*
@@ -108,8 +104,7 @@ 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;
 	}
@@ -136,8 +131,7 @@ 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();
@@ -148,8 +142,7 @@ 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);
 }