[PATCH net-next] hyperv: Increase the buffer length for netvsc_channel_cb()

When the buffer is too small for a packet from VMBus, a bigger buffer will be
allocated in netvsc_channel_cb() and retry reading the packet from VMBus.
Increasing this buffer size will reduce the retry overhead.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
---
 drivers/net/hyperv/hyperv_net.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 24441ae..3960acd 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h

@@ -591,7 +591,7 @@ struct nvsp_message {
 
 #define NETVSC_RECEIVE_BUFFER_ID		0xcafe
 
-#define NETVSC_PACKET_SIZE                      2048
+#define NETVSC_PACKET_SIZE                      4096
 
 #define VRSS_SEND_TAB_SIZE 16
 

-- 
1.7.1

From: Haiyang Zhang <redacted>
Date: Fri,  1 Aug 2014 15:55:30 +0000

When the buffer is too small for a packet from VMBus, a bigger buffer will be
allocated in netvsc_channel_cb() and retry reading the packet from VMBus.
Increasing this buffer size will reduce the retry overhead.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>

I'm not applying this, sorry.

I said that because the structure that contains this buffer is now
larger than a page, you should allocate the CB buffer externally
via another kmalloc() or via the page allocator.

-----Original Message-----
From: David Miller [mailto:davem@davemloft.net]
Sent: Tuesday, August 5, 2014 4:04 PM
To: thomas1206@gmail.com
Cc: netdev@vger.kernel.org; Haiyang Zhang; KY Srinivasan; olaf@aepfle.de;
jasowang@redhat.com; linux-kernel@vger.kernel.org; driverdev-
devel@linuxdriverproject.org
Subject: Re: [PATCH net-next] hyperv: Increase the buffer length for
netvsc_channel_cb()

From: Haiyang Zhang <redacted>
Date: Fri,  1 Aug 2014 15:55:30 +0000

quoted

When the buffer is too small for a packet from VMBus, a bigger buffer

will be

quoted

allocated in netvsc_channel_cb() and retry reading the packet from

VMBus.

quoted

Increasing this buffer size will reduce the retry overhead.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>

I'm not applying this, sorry.

I said that because the structure that contains this buffer is now
larger than a page, you should allocate the CB buffer externally
via another kmalloc() or via the page allocator.

This must have been re-sent accidentally when we are updating our 
Email server... I will update the patch and re-submit it soon.

Thanks,
- Haiyang