virtio-pmem: add trace events

This patch adds trace events for virtio-pmem functionality.
Adding trace events for virtio pmem request, reponse and host
side fsync functionality.

Signed-off-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Message-Id: <20201117115705.32195-1-pankaj.gupta.linux@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/virtio/trace-events

@@ -122,3 +122,8 @@ virtio_mem_unplug_all_request(void) ""
 virtio_mem_resized_usable_region(uint64_t old_size, uint64_t new_size) "old_size=0x%" PRIx64 "new_size=0x%" PRIx64
 virtio_mem_state_request(uint64_t addr, uint16_t nb_blocks) "addr=0x%" PRIx64 " nb_blocks=%" PRIu16
 virtio_mem_state_response(uint16_t state) "state=%" PRIu16
+
+# virtio-pmem.c
+virtio_pmem_flush_request(void) "flush request"
+virtio_pmem_response(void) "flush response"
+virtio_pmem_flush_done(int type) "fsync return=%d"

hw/virtio/virtio-pmem.c

@@ -24,6 +24,7 @@
 #include "sysemu/hostmem.h"
 #include "block/aio.h"
 #include "block/thread-pool.h"
+#include "trace.h"
 
 typedef struct VirtIODeviceRequest {
     VirtQueueElement elem;
@@ -41,6 +42,7 @@ static int worker_cb(void *opaque)
 
     /* flush raw backing image */
     err = fsync(req_data->fd);
+    trace_virtio_pmem_flush_done(err);
     if (err != 0) {
         err = 1;
     }
@@ -59,6 +61,7 @@ static void done_cb(void *opaque, int ret)
     /* Callbacks are serialized, so no need to use atomic ops. */
     virtqueue_push(req_data->pmem->rq_vq, &req_data->elem, len);
     virtio_notify((VirtIODevice *)req_data->pmem, req_data->pmem->rq_vq);
+    trace_virtio_pmem_response();
     g_free(req_data);
 }
 
@@ -69,6 +72,7 @@ static void virtio_pmem_flush(VirtIODevice *vdev, VirtQueue *vq)
     HostMemoryBackend *backend = MEMORY_BACKEND(pmem->memdev);
     ThreadPool *pool = aio_get_thread_pool(qemu_get_aio_context());
 
+    trace_virtio_pmem_flush_request();
     req_data = virtqueue_pop(vq, sizeof(VirtIODeviceRequest));
     if (!req_data) {
         virtio_error(vdev, "virtio-pmem missing request data");