[win-pv-devel] [PATCH 3/3] Defer transmit response event until the last possible moment

[Paul Durrant <pdurrant@xxxxxxxxx>]

When sending packets, there is no need to enable a transmit reponse
event until the ring fills or there are no more packets to send.

This patch therefore defers advancing the ring event count until just
before a batch of packets are pushed.

Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
 src/xenvif/transmitter.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/xenvif/transmitter.c b/src/xenvif/transmitter.c
index 95c3479..b55daa3 100644
--- a/src/xenvif/transmitter.c
+++ b/src/xenvif/transmitter.c
@@ -2604,7 +2604,6 @@ TransmitterRingPoll(
         KeMemoryBarrier();
 
         Ring->Front.rsp_cons = rsp_cons;
-        Ring->Shared->rsp_event = rsp_cons + 1;
     }
 
 done:
@@ -2678,6 +2677,8 @@ __TransmitterRingPushRequests(
 #pragma warning (push)
 #pragma warning (disable:4244)
 
+    Ring->Shared->rsp_event = Ring->Front.req_prod_pvt;
+
     // Make the requests visible to the backend
     RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&Ring->Front, Notify);
 
-- 
2.1.1


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