Re: [PATCH] openvswitch: Add cutlen info to upcall.

Hi Pravin,

Yes, I think that's better. Instead of cutlen, I will pass the
skb->len to userspace.

Regards,
William

On Wed, Jun 15, 2016 at 7:55 PM, pravin shelar [off-list ref] wrote:

On Wed, Jun 15, 2016 at 7:28 PM, William Tu [off-list ref] wrote:

quoted

The commit f2a4d086ed4c ("openvswitch: Add packet truncation support.")
introduces packet truncation before sending to userspace upcall receiver.
This patch passes the number of bytes truncated in kernel to so that the
upcall receiver knows the original packet size. Potentially this will
be used by sFlow, where OVS translates sFlow config header=N to a sample
action to trunc(N) in kernel datapath. Thus, only N bytes instead of
full-packet size will be copied from kernel to userspace, saving the
kernel-to-userspace bandwidth.

Signed-off-by: William Tu <redacted>
Cc: Pravin Shelar <redacted>

This is passing unnecessary kernel implementation details to
userspace, can we just pass skb-len to userspace?