binder: add trace at free transaction.

Since the original trace_binder_transaction_received cannot
precisely present the real finished time of transaction, adding a
trace_binder_txn_latency_free at the point of free transaction
may be more close to it.

Signed-off-by: Frankie.Chang <Frankie.Chang@mediatek.com>
Acked-by: Todd Kjos <tkjos@google.com>
Link: https://lore.kernel.org/r/1605063764-12930-3-git-send-email-Frankie.Chang@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/android/binder.c

@@ -1486,6 +1486,20 @@ static void binder_free_txn_fixups(struct binder_transaction *t)
 	}
 }
 
+static void binder_txn_latency_free(struct binder_transaction *t)
+{
+	int from_proc, from_thread, to_proc, to_thread;
+
+	spin_lock(&t->lock);
+	from_proc = t->from ? t->from->proc->pid : 0;
+	from_thread = t->from ? t->from->pid : 0;
+	to_proc = t->to_proc ? t->to_proc->pid : 0;
+	to_thread = t->to_thread ? t->to_thread->pid : 0;
+	spin_unlock(&t->lock);
+
+	trace_binder_txn_latency_free(t, from_proc, from_thread, to_proc, to_thread);
+}
+
 static void binder_free_transaction(struct binder_transaction *t)
 {
 	struct binder_proc *target_proc = t->to_proc;
@@ -1496,6 +1510,8 @@ static void binder_free_transaction(struct binder_transaction *t)
 			t->buffer->transaction = NULL;
 		binder_inner_proc_unlock(target_proc);
 	}
+	if (trace_binder_txn_latency_free_enabled())
+		binder_txn_latency_free(t);
 	/*
 	 * If the transaction has no target_proc, then
 	 * t->buffer->transaction has already been cleared.
@@ -3073,6 +3089,8 @@ err_get_secctx_failed:
 	kfree(tcomplete);
 	binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
 err_alloc_tcomplete_failed:
+	if (trace_binder_txn_latency_free_enabled())
+		binder_txn_latency_free(t);
 	kfree(t);
 	binder_stats_deleted(BINDER_STAT_TRANSACTION);
 err_alloc_t_failed:

drivers/android/binder_trace.h

@@ -95,6 +95,35 @@ TRACE_EVENT(binder_wait_for_work,
 		  __entry->thread_todo)
 );
 
+TRACE_EVENT(binder_txn_latency_free,
+	TP_PROTO(struct binder_transaction *t,
+		 int from_proc, int from_thread,
+		 int to_proc, int to_thread),
+	TP_ARGS(t, from_proc, from_thread, to_proc, to_thread),
+	TP_STRUCT__entry(
+		__field(int, debug_id)
+		__field(int, from_proc)
+		__field(int, from_thread)
+		__field(int, to_proc)
+		__field(int, to_thread)
+		__field(unsigned int, code)
+		__field(unsigned int, flags)
+	),
+	TP_fast_assign(
+		__entry->debug_id = t->debug_id;
+		__entry->from_proc = from_proc;
+		__entry->from_thread = from_thread;
+		__entry->to_proc = to_proc;
+		__entry->to_thread = to_thread;
+		__entry->code = t->code;
+		__entry->flags = t->flags;
+	),
+	TP_printk("transaction=%d from %d:%d to %d:%d flags=0x%x code=0x%x",
+		  __entry->debug_id, __entry->from_proc, __entry->from_thread,
+		  __entry->to_proc, __entry->to_thread, __entry->code,
+		  __entry->flags)
+);
+
 TRACE_EVENT(binder_transaction,
 	TP_PROTO(bool reply, struct binder_transaction *t,
 		 struct binder_node *target_node),