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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>
This commit is contained in:
Dexuan Cui 2016-01-27 22:29:39 -08:00 committed by Greg Kroah-Hartman
parent e8d6ca023e
commit 5f363bc38f
1 changed files with 5 additions and 1 deletions
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6
drivers/hv/channel.c
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@ -659,6 +659,9 @@ int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer,
* 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 @@ int vmbus_sendpacket_ctl(struct vmbus_channel *channel, void *buffer,
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;