hyper-v: trace channel events

Added an additional set of trace points for when channel gets notified
or signals host.

Suggested-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hv/channel.c

@@ -43,6 +43,8 @@ void vmbus_setevent(struct vmbus_channel *channel)
 {
 	struct hv_monitor_page *monitorpage;
 
+	trace_vmbus_setevent(channel);
+
 	/*
 	 * For channels marked as in "low latency" mode
 	 * bypass the monitor page mechanism.

drivers/hv/connection.c

@@ -322,6 +322,8 @@ void vmbus_on_event(unsigned long data)
 	struct vmbus_channel *channel = (void *) data;
 	unsigned long time_limit = jiffies + 2;
 
+	trace_vmbus_on_event(channel);
+
 	do {
 		void (*callback_fn)(void *);
 

drivers/hv/hv_trace.h

@@ -294,6 +294,29 @@ TRACE_EVENT(vmbus_send_tl_connect_request,
 		    )
 	);
 
+DECLARE_EVENT_CLASS(vmbus_channel,
+	TP_PROTO(const struct vmbus_channel *channel),
+	TP_ARGS(channel),
+	TP_STRUCT__entry(__field(u32, relid)),
+	TP_fast_assign(__entry->relid = channel->offermsg.child_relid),
+	TP_printk("relid 0x%x", __entry->relid)
+);
+
+DEFINE_EVENT(vmbus_channel, vmbus_chan_sched,
+	    TP_PROTO(const struct vmbus_channel *channel),
+	    TP_ARGS(channel)
+);
+
+DEFINE_EVENT(vmbus_channel, vmbus_setevent,
+	    TP_PROTO(const struct vmbus_channel *channel),
+	    TP_ARGS(channel)
+);
+
+DEFINE_EVENT(vmbus_channel, vmbus_on_event,
+	    TP_PROTO(const struct vmbus_channel *channel),
+	    TP_ARGS(channel)
+);
+
 #undef TRACE_INCLUDE_PATH
 #define TRACE_INCLUDE_PATH .
 #undef TRACE_INCLUDE_FILE

drivers/hv/vmbus_drv.c

@@ -946,6 +946,8 @@ static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu)
 			if (channel->rescind)
 				continue;
 
+			trace_vmbus_chan_sched(channel);
+
 			++channel->interrupts;
 
 			switch (channel->callback_mode) {