[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [PATCH net-next v2] xen-netback: Rework rx_work_todo

On 04/02/14 19:19, Zoltan Kiss wrote:
On 20/01/14 16:38, Wei Liu wrote:
On Wed, Jan 15, 2014 at 05:11:07PM +0000, Zoltan Kiss wrote:
The recent patch to fix receive side flow control (11b57f) solved the
thread problem, however caused an another one. The receive side can
stall, if:
- [THREAD] xenvif_rx_action sets rx_queue_stopped to true
- [INTERRUPT] interrupt happens, and sets rx_event to true
- [THREAD] then xenvif_kthread sets rx_event to false
- [THREAD] rx_work_todo doesn't return true anymore

Also, if interrupt sent but there is still no room in the ring, it
take quite a
long time until xenvif_rx_action realize it. This patch ditch that
two variable,
and rework rx_work_todo. If the thread finds it can't fit more skb's
into the
ring, it saves the last slot estimation into rx_last_skb_slots,
otherwise it's
kept as 0. Then rx_work_todo will check if:
- there is something to send to the ring (like before)
- there is space for the topmost packet in the queue

I think that's more natural and optimal thing to test than two bool
which are
set somewhere else.

Signed-off-by: Zoltan Kiss <zoltan.kiss@xxxxxxxxxx>

Sorry for the delay.

Paul, thanks for reviewing.

Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>


This patch haven't made it to net-next yet, maybe because the subject
doesn't suggest that this is a bugfix. I suggest to apply it as soon as
possible, otherwise netback will be quite broken.

I've reposted it with clearer subject, sorry for being too vague


Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.