[1/5] xfs: track deferred ops statistics

Commit Message

Darrick J. Wong Dec. 31, 2024, 11:36 p.m. UTC

From: Darrick J. Wong <[e-mail]>

Track some basic statistics on how hard we're pushing the defer ops.

Signed-off-by: "Darrick J. Wong" <[e-mail]>
---
 fs/xfs/libxfs/xfs_defer.c |   18 +++++++++++++++++-
 fs/xfs/xfs_trace.h        |   19 +++++++++++++++++++
 fs/xfs/xfs_trans.c        |    3 +++
 fs/xfs/xfs_trans.h        |    7 +++++++
 4 files changed, 46 insertions(+), 1 deletion(-)

Patch

diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c
index 5b377cbbb1f7e0..236409a3333ea6 100644
--- a/fs/xfs/libxfs/xfs_defer.c
+++ b/fs/xfs/libxfs/xfs_defer.c
@@ -618,6 +618,8 @@  xfs_defer_finish_one(
 	/* Done with the dfp, free it. */
 	list_del(&dfp->dfp_list);
 	kmem_cache_free(xfs_defer_pending_cache, dfp);
+	tp->t_dfops_nr--;
+	tp->t_dfops_finished++;
 out:
 	if (ops->finish_cleanup)
 		ops->finish_cleanup(tp, state, error);
@@ -680,6 +682,9 @@  xfs_defer_finish_noroll(
 
 		list_splice_init(&(*tp)->t_dfops, &dop_pending);
 
+		(*tp)->t_dfops_nr_max = max((*tp)->t_dfops_nr,
+					    (*tp)->t_dfops_nr_max);
+
 		if (has_intents < 0) {
 			error = has_intents;
 			goto out_shutdown;
@@ -721,6 +726,7 @@  xfs_defer_finish_noroll(
 	xfs_force_shutdown((*tp)->t_mountp, SHUTDOWN_CORRUPT_INCORE);
 	trace_xfs_defer_finish_error(*tp, error);
 	xfs_defer_cancel_list((*tp)->t_mountp, &dop_pending);
+	(*tp)->t_dfops_nr = 0;
 	xfs_defer_cancel(*tp);
 	return error;
 }
@@ -768,6 +774,7 @@  xfs_defer_cancel(
 	trace_xfs_defer_cancel(tp, _RET_IP_);
 	xfs_defer_trans_abort(tp, &tp->t_dfops);
 	xfs_defer_cancel_list(mp, &tp->t_dfops);
+	tp->t_dfops_nr = 0;
 }
 
 /*
@@ -853,8 +860,10 @@  xfs_defer_add(
 	}
 
 	dfp = xfs_defer_find_last(tp, ops);
-	if (!dfp || !xfs_defer_can_append(dfp, ops))
+	if (!dfp || !xfs_defer_can_append(dfp, ops)) {
 		dfp = xfs_defer_alloc(&tp->t_dfops, ops);
+		tp->t_dfops_nr++;
+	}
 
 	xfs_defer_add_item(dfp, li);
 	trace_xfs_defer_add_item(tp->t_mountp, dfp, li);
@@ -879,6 +888,7 @@  xfs_defer_add_barrier(
 		return;
 
 	xfs_defer_alloc(&tp->t_dfops, &xfs_barrier_defer_type);
+	tp->t_dfops_nr++;
 
 	trace_xfs_defer_add_item(tp->t_mountp, dfp, NULL);
 }
@@ -939,6 +949,12 @@  xfs_defer_move(
 	struct xfs_trans	*stp)
 {
 	list_splice_init(&stp->t_dfops, &dtp->t_dfops);
+	dtp->t_dfops_nr += stp->t_dfops_nr;
+	dtp->t_dfops_nr_max = stp->t_dfops_nr_max;
+	dtp->t_dfops_finished = stp->t_dfops_finished;
+	stp->t_dfops_nr = 0;
+	stp->t_dfops_nr_max = 0;
+	stp->t_dfops_finished = 0;
 
 	/*
 	 * Low free space mode was historically controlled by a dfops field.
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 8d86a1e038cd5c..0352f432421598 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -2880,6 +2880,25 @@  TRACE_EVENT(xfs_btree_free_block,
 /* deferred ops */
 struct xfs_defer_pending;
 
+TRACE_EVENT(xfs_defer_stats,
+	TP_PROTO(struct xfs_trans *tp),
+	TP_ARGS(tp),
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(unsigned int, max)
+		__field(unsigned int, finished)
+	),
+	TP_fast_assign(
+		__entry->dev = tp->t_mountp->m_super->s_dev;
+		__entry->max = tp->t_dfops_nr_max;
+		__entry->finished = tp->t_dfops_finished;
+	),
+	TP_printk("dev %d:%d max %u finished %u",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->max,
+		  __entry->finished)
+)
+
 DECLARE_EVENT_CLASS(xfs_defer_class,
 	TP_PROTO(struct xfs_trans *tp, unsigned long caller_ip),
 	TP_ARGS(tp, caller_ip),
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index f53f82456288e5..269cd4583a033d 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -71,6 +71,9 @@  xfs_trans_free(
 	xfs_extent_busy_sort(&tp->t_busy);
 	xfs_extent_busy_clear(&tp->t_busy, false);
 
+	if (tp->t_dfops_finished > 0)
+		trace_xfs_defer_stats(tp);
+
 	trace_xfs_trans_free(tp, _RET_IP_);
 	xfs_trans_clear_context(tp);
 	if (!(tp->t_flags & XFS_TRANS_NO_WRITECOUNT))
diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index 71c2e82e4dadff..cb037a669754eb 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -153,6 +153,13 @@  typedef struct xfs_trans {
 	struct list_head	t_busy;		/* list of busy extents */
 	struct list_head	t_dfops;	/* deferred operations */
 	unsigned long		t_pflags;	/* saved process flags state */
+
+	/* Count of deferred ops attached to transaction. */
+	unsigned int		t_dfops_nr;
+	/* Maximum t_dfops_nr seen in a loop. */
+	unsigned int		t_dfops_nr_max;
+	/* Number of dfops finished. */
+	unsigned int		t_dfops_finished;
 } xfs_trans_t;
 
 /*