[Qemu-devel] [RFC Patch 05/10] The draining timer, create a timer to purge the packets from the cached pool.

[wexu@redhat.com]

Signed-off-by: Wei Xu <wexu@redhat.com>
---
 hw/net/virtio-net.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index d005a56..8da2815 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -48,12 +48,17 @@
 
 #define MAX_VIRTIO_IP_PAYLOAD  (65535 + IP_OFFSET)
 
+/* Purge coalesced packets timer interval */
+#define RSC_TIMER_INTERVAL  500000
+
 /* Global statistics */
 static uint32_t rsc_chain_no_mem;
 
 /* Switcher to enable/disable rsc */
 static bool virtio_net_rsc_bypass;
 
+static uint32_t rsc_timeout = RSC_TIMER_INTERVAL;
+
 /* Coalesce callback for ipv4/6 */
 typedef int32_t (VirtioNetCoalesce) (NetRscChain *chain, NetRscSeg *seg,
                                      const uint8_t *buf, size_t size);
@@ -1625,6 +1630,35 @@ static int virtio_net_load_device(VirtIODevice *vdev, QEMUFile *f,
     return 0;
 }
 
+static void virtio_net_rsc_purge(void *opq)
+{
+    int ret = 0;
+    NetRscChain *chain = (NetRscChain *)opq;
+    NetRscSeg *seg, *rn;
+
+    QTAILQ_FOREACH_SAFE(seg, &chain->buffers, next, rn) {
+        if (!qemu_can_send_packet(seg->nc)) {
+            /* Should quit or continue? not sure if one or some
+            * of the queues fail would happen, try continue here */
+            continue;
+        }
+
+        ret = virtio_net_do_receive(seg->nc, seg->buf, seg->size);
+        QTAILQ_REMOVE(&chain->buffers, seg, next);
+        g_free(seg->buf);
+        g_free(seg);
+
+        if (ret == 0) {
+            /* Try next queue */
+            continue;
+        }
+    }
+
+    if (!QTAILQ_EMPTY(&chain->buffers)) {
+        timer_mod(chain->drain_timer,
+                  qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + rsc_timeout);
+    }
+}
 
 static void virtio_net_rsc_cleanup(VirtIONet *n)
 {
@@ -1810,6 +1844,8 @@ static size_t virtio_net_rsc_callback(NetRscChain *chain, NetClientState *nc,
         if (!virtio_net_rsc_cache_buf(chain, nc, buf, size)) {
             return 0;
         } else {
+            timer_mod(chain->drain_timer,
+                      qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + rsc_timeout);
             return size;
         }
     }
@@ -1877,6 +1913,8 @@ static NetRscChain *virtio_net_rsc_lookup_chain(NetClientState *nc,
     }
 
     chain->proto = proto;
+    chain->drain_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
+                                      virtio_net_rsc_purge, chain);
     chain->do_receive = virtio_net_rsc_receive4;
 
     QTAILQ_INIT(&chain->buffers);
-- 
2.4.0