Drivers: hv: vmbus: vmbus_sendpacket_ctl: hvsock: avoid unnecessary signaling
When the hvsock channel's outbound ringbuffer is full (i.e.,
hv_ringbuffer_write() returns -EAGAIN), we should avoid the unnecessary
signaling the host.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 1161d68..3f04533 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -659,6 +659,9 @@
* If we cannot write to the ring-buffer; signal the host
* even if we may not have written anything. This is a rare
* enough condition that it should not matter.
+ * NOTE: in this case, the hvsock channel is an exception, because
+ * it looks the host side's hvsock implementation has a throttling
+ * mechanism which can hurt the performance otherwise.
*/
if (channel->signal_policy)
@@ -666,7 +669,8 @@
else
kick_q = true;
- if (((ret == 0) && kick_q && signal) || (ret))
+ if (((ret == 0) && kick_q && signal) ||
+ (ret && !is_hvsock_channel(channel)))
vmbus_setevent(channel);
return ret;