[Linux-cachefs] [PATCH 1/3] fscache: add tracepoints to fscache_parent_ready and fscache_done_parent_op

[Jeff Layton]

Add some tracepoints for tracking acquisition and release of parent
references.

Signed-off-by: Jeff Layton <jlay...@kernel.org>
---
 fs/fscache/object.c            |  2 ++
 include/trace/events/fscache.h | 29 +++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/fs/fscache/object.c b/fs/fscache/object.c
index 3eac39ad3fae..a42b206c0659 100644
--- a/fs/fscache/object.c
+++ b/fs/fscache/object.c
@@ -156,6 +156,7 @@ static inline void fscache_done_parent_op(struct 
fscache_object *object)
        spin_lock_nested(&parent->lock, 1);
        parent->n_obj_ops--;
        parent->n_ops--;
+       trace_fscache_parent(object, true);
        if (parent->n_ops == 0)
                fscache_raise_event(parent, FSCACHE_OBJECT_EV_CLEARED);
        spin_unlock(&parent->lock);
@@ -437,6 +438,7 @@ static const struct fscache_state 
*fscache_parent_ready(struct fscache_object *o
        parent->n_ops++;
        parent->n_obj_ops++;
        object->lookup_jif = jiffies;
+       trace_fscache_parent(object, false);
        spin_unlock(&parent->lock);
 
        _leave("");
diff --git a/include/trace/events/fscache.h b/include/trace/events/fscache.h
index dd2c794b5489..4c28aafcbb84 100644
--- a/include/trace/events/fscache.h
+++ b/include/trace/events/fscache.h
@@ -329,6 +329,35 @@ TRACE_EVENT(fscache_disable,
                      __entry->n_children, __entry->n_active, __entry->flags)
            );
 
+TRACE_EVENT(fscache_parent,
+           TP_PROTO(struct fscache_object *obj, bool done),
+
+           TP_ARGS(obj, done),
+
+           TP_STRUCT__entry(
+                   __field(unsigned int,       cookie     )
+                   __field(unsigned int,       parent     )
+                   __field(int,                n_obj_ops  )
+                   __field(int,                n_ops      )
+                   __field(int,                n_children )
+                   __field(bool,               done       )
+                            ),
+
+           TP_fast_assign(
+                   __entry->cookie     = obj->cookie->debug_id;
+                   __entry->parent     = obj->parent->cookie->debug_id;
+                   __entry->n_obj_ops  = obj->parent->n_obj_ops;
+                   __entry->n_ops      = obj->parent->n_ops;
+                   __entry->n_children = obj->parent->n_children;
+                   __entry->done       = done;
+                          ),
+
+           TP_printk("c=%08x pc=%08x Noo=%d No=%d Nc=%d %s",
+                     __entry->cookie, __entry->parent, __entry->n_obj_ops,
+                     __entry->n_ops, __entry->n_children,
+                     __entry->done ? "DONE" : "READY")
+           );
+
 TRACE_EVENT(fscache_osm,
            TP_PROTO(struct fscache_object *object,
                     const struct fscache_state *state,
-- 
2.21.0

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