[Spice-devel] [PATCH 14/20] Use GQueue for RedCharDevice::send_queue
Jonathon Jongsma
jjongsma at redhat.com
Fri Apr 15 20:01:37 UTC 2016
On Thu, 2016-04-14 at 16:50 -0500, Jonathon Jongsma wrote:
> From: Christophe Fergeau <cfergeau at redhat.com>
>
> There was an extra RedCharDeviceMsgToClientItem type whose only
> purpose was to manage a linked list of items to send. GQueue has the
> same purpose as this type in addition to being generic. As the length of
> the send queue is tracked, a GQueue is more appropriate than a GList and
> allow to remove RedCharDevice::send_queue_size.
> ---
> server/char-device.c | 69 ++++++++++++++++++---------------------------------
> -
> 1 file changed, 23 insertions(+), 46 deletions(-)
>
> diff --git a/server/char-device.c b/server/char-device.c
> index f3e16da..6b9596e 100644
> --- a/server/char-device.c
> +++ b/server/char-device.c
> @@ -41,8 +41,7 @@ struct RedCharDeviceClient {
> uint64_t num_send_tokens; /* send to client */
> SpiceTimer *wait_for_tokens_timer;
> int wait_for_tokens_started;
> - Ring send_queue;
> - uint32_t send_queue_size;
> + GQueue *send_queue;
> uint32_t max_send_queue_size;
> };
>
> @@ -105,11 +104,6 @@ static guint signals[RED_CHAR_DEVICE_LAST_SIGNAL];
> static void red_char_device_write_buffer_unref(RedCharDeviceWriteBuffer
> *write_buf);
> static void red_char_device_write_retry(void *opaque);
>
> -typedef struct RedCharDeviceMsgToClientItem {
> - RingItem link;
> - PipeItem *msg;
> -} RedCharDeviceMsgToClientItem;
> -
> static PipeItem *
> red_char_device_read_one_msg_from_device(RedCharDevice *dev)
> {
> @@ -187,19 +181,10 @@ static void
> red_char_device_write_buffer_pool_add(RedCharDevice *dev,
> static void red_char_device_client_send_queue_free(RedCharDevice *dev,
> RedCharDeviceClient
> *dev_client)
> {
> - spice_debug("send_queue_empty %d", ring_is_empty(&dev_client
> ->send_queue));
> - while (!ring_is_empty(&dev_client->send_queue)) {
> - RingItem *item = ring_get_tail(&dev_client->send_queue);
> - RedCharDeviceMsgToClientItem *msg_item = SPICE_CONTAINEROF(item,
> -
> RedCharDeviceMsgToClientItem,
> - link);
> -
> - ring_remove(item);
> - pipe_item_unref(msg_item->msg);
> - free(msg_item);
> - }
> - dev_client->num_send_tokens += dev_client->send_queue_size;
> - dev_client->send_queue_size = 0;
> + spice_debug("send_queue_empty %d", g_queue_is_empty(dev_client
> ->send_queue));
> + g_queue_free_full(dev_client->send_queue, pipe_item_unref);
> + g_queue_clear(dev_client->send_queue);
> + dev_client->num_send_tokens += g_queue_get_length(dev_client
> ->send_queue);
This looks wrong. We're calling g_queue_get_length() immediately after clearing
the queue, so it's guaranteed to be 0. This last line should be moved before the
g_queue_free_full() call.
> }
>
> static void red_char_device_client_free(RedCharDevice *dev,
> @@ -303,17 +288,14 @@ static void
> red_char_device_add_msg_to_client_queue(RedCharDeviceClient *dev_cli
> PipeItem *msg)
> {
> RedCharDevice *dev = dev_client->dev;
> - RedCharDeviceMsgToClientItem *msg_item;
>
> - if (dev_client->send_queue_size >= dev_client->max_send_queue_size) {
> + if (g_queue_get_length(dev_client->send_queue) >= dev_client
> ->max_send_queue_size) {
> red_char_device_handle_client_overflow(dev_client);
> return;
> }
>
> - msg_item = spice_new0(RedCharDeviceMsgToClientItem, 1);
> - msg_item->msg = pipe_item_ref(msg);
> - ring_add(&dev_client->send_queue, &msg_item->link);
> - dev_client->send_queue_size++;
> + pipe_item_ref(msg);
> + g_queue_push_head(dev_client->send_queue, msg);
> if (!dev_client->wait_for_tokens_started) {
> reds_core_timer_start(dev->priv->reds, dev_client
> ->wait_for_tokens_timer,
> RED_CHAR_DEVICE_WAIT_TOKENS_TIMEOUT);
> @@ -332,7 +314,7 @@ static void
> red_char_device_send_msg_to_clients(RedCharDevice *dev,
> dev_client = SPICE_CONTAINEROF(item, RedCharDeviceClient, link);
> if (red_char_device_can_send_to_client(dev_client)) {
> dev_client->num_send_tokens--;
> - spice_assert(ring_is_empty(&dev_client->send_queue));
> + spice_assert(g_queue_is_empty(dev_client->send_queue));
> red_char_device_send_msg_to_client(dev, msg, dev_client->client);
>
> /* don't refer to dev_client anymore, it may have been released
> */
> @@ -394,21 +376,17 @@ static int
> red_char_device_read_from_device(RedCharDevice *dev)
>
> static void red_char_device_client_send_queue_push(RedCharDeviceClient
> *dev_client)
> {
> - RingItem *item;
> - while ((item = ring_get_tail(&dev_client->send_queue)) &&
> - red_char_device_can_send_to_client(dev_client)) {
> - RedCharDeviceMsgToClientItem *msg_item;
> -
> - msg_item = SPICE_CONTAINEROF(item, RedCharDeviceMsgToClientItem,
> link);
> - ring_remove(item);
> -
> + while (!g_queue_is_empty(dev_client->send_queue)) {
> + GList *msg;
GList* ?? Doesn't this GQueue contain PipeItem*?
> + if (!red_char_device_can_send_to_client(dev_client)) {
> + break;
> + }
> + msg = g_queue_pop_tail(dev_client->send_queue);
> + g_assert(msg != NULL);
> dev_client->num_send_tokens--;
> - red_char_device_send_msg_to_client(dev_client->dev,
> - msg_item->msg,
> + red_char_device_send_msg_to_client(dev_client->dev, msg->data,
I think the second argument should simply be 'msg' instead of 'msg->data', no? I
wonder why it works...
> dev_client->client);
> - pipe_item_unref(msg_item->msg);
> - dev_client->send_queue_size--;
> - free(msg_item);
> + pipe_item_unref(msg);
...and here, we free this GList* variable by calling pipe_item_unref(). That's
one of the pitfalls of making pipe_item_unref() accept a gpointer argument --
the compiler didn't warn us...
> }
> }
>
> @@ -418,7 +396,7 @@ static void
> red_char_device_send_to_client_tokens_absorb(RedCharDeviceClient *de
> RedCharDevice *dev = dev_client->dev;
> dev_client->num_send_tokens += tokens;
>
> - if (dev_client->send_queue_size) {
> + if (g_queue_get_length(dev_client->send_queue)) {
> spice_assert(dev_client->num_send_tokens == tokens);
> red_char_device_client_send_queue_push(dev_client);
> }
> @@ -427,7 +405,7 @@ static void
> red_char_device_send_to_client_tokens_absorb(RedCharDeviceClient *de
> reds_core_timer_cancel(dev->priv->reds, dev_client
> ->wait_for_tokens_timer);
> dev_client->wait_for_tokens_started = FALSE;
> red_char_device_read_from_device(dev_client->dev);
> - } else if (dev_client->send_queue_size) {
> + } else if (!g_queue_is_empty(dev_client->send_queue)) {
> reds_core_timer_start(dev->priv->reds, dev_client
> ->wait_for_tokens_timer,
> RED_CHAR_DEVICE_WAIT_TOKENS_TIMEOUT);
> dev_client->wait_for_tokens_started = TRUE;
> @@ -751,8 +729,7 @@ static RedCharDeviceClient
> *red_char_device_client_new(RedClient *client,
>
> dev_client = spice_new0(RedCharDeviceClient, 1);
> dev_client->client = client;
> - ring_init(&dev_client->send_queue);
> - dev_client->send_queue_size = 0;
> + dev_client->send_queue = g_queue_new();
> dev_client->max_send_queue_size = max_send_queue_size;
> dev_client->do_flow_control = do_flow_control;
> if (do_flow_control) {
> @@ -934,9 +911,9 @@ void red_char_device_migrate_data_marshall(RedCharDevice
> *dev,
> RedCharDeviceClient,
> link);
> /* FIXME: if there were more than one client before the marshalling,
> - * it is possible that the send_queue_size > 0, and the send data
> + * it is possible that the send_queue length > 0, and the send data
> * should be migrated as well */
> - spice_assert(dev_client->send_queue_size == 0);
> + spice_assert(g_queue_is_empty(dev_client->send_queue));
> spice_marshaller_add_uint32(m, SPICE_MIGRATE_DATA_CHAR_DEVICE_VERSION);
> spice_marshaller_add_uint8(m, 1); /* connected */
> spice_marshaller_add_uint32(m, dev_client->num_client_tokens);
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