Messages in this thread | | | Date | Tue, 4 Feb 2014 19:55:42 +0000 | From | Zoltan Kiss <> | Subject | Re: [PATCH net-next v2] xen-netback: Rework rx_work_todo |
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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 >>> spinning >>> 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@citrix.com> >> >> Sorry for the delay. >> >> Paul, thanks for reviewing. >> >> Acked-by: Wei Liu <wei.liu2@citrix.com> > > Hi, > > 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
Zoli
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