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Date: Tue, 4 Feb 2014 19:19:00 +0000 From: Zoltan Kiss <zoltan.kiss@...rix.com> To: Wei Liu <wei.liu2@...rix.com> CC: <ian.campbell@...rix.com>, <xen-devel@...ts.xenproject.org>, <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>, <jonathan.davies@...rix.com>, David Miller <davem@...emloft.net> Subject: Re: [PATCH net-next v2] xen-netback: Rework rx_work_todo 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@...rix.com> > > Sorry for the delay. > > Paul, thanks for reviewing. > > Acked-by: Wei Liu <wei.liu2@...rix.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. Zoli -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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