From bcd925929882618b3e4daf85f654f009d25bf32f Mon Sep 17 00:00:00 2001 From: Vineeth Remanan Pillai Date: Tue, 7 Feb 2017 18:59:01 +0000 Subject: [PATCH] xen-netfront: Rework the fix for Rx stall during OOM and network stress The commit de95166792de ("xen-netfront: Fix Rx stall during network stress and OOM") caused the refill timer to be triggerred almost on all invocations of xennet_alloc_rx_buffers for certain workloads. This reworks the fix by reverting to the old behaviour and taking into consideration the skb allocation failure. Refill timer is now triggered on insufficient requests or skb allocation failure. Signed-off-by: Vineeth Remanan Pillai Fixes: de95166792de (xen-netfront: Fix Rx stall during network stress and OOM) Reported-by: Boris Ostrovsky Reviewed-by: Boris Ostrovsky Signed-off-by: David S. Miller --- drivers/net/xen-netfront.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 8315fe73ecd04..9dba69731f307 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -281,6 +281,7 @@ static void xennet_alloc_rx_buffers(struct netfront_queue *queue) { RING_IDX req_prod = queue->rx.req_prod_pvt; int notify; + int err = 0; if (unlikely(!netif_carrier_ok(queue->info->netdev))) return; @@ -295,8 +296,10 @@ static void xennet_alloc_rx_buffers(struct netfront_queue *queue) struct xen_netif_rx_request *req; skb = xennet_alloc_one_rx_buffer(queue); - if (!skb) + if (!skb) { + err = -ENOMEM; break; + } id = xennet_rxidx(req_prod); @@ -320,8 +323,13 @@ static void xennet_alloc_rx_buffers(struct netfront_queue *queue) queue->rx.req_prod_pvt = req_prod; - /* Not enough requests? Try again later. */ - if (req_prod - queue->rx.sring->req_prod < NET_RX_SLOTS_MIN) { + /* Try again later if there are not enough requests or skb allocation + * failed. + * Enough requests is quantified as the sum of newly created slots and + * the unconsumed slots at the backend. + */ + if (req_prod - queue->rx.rsp_cons < NET_RX_SLOTS_MIN || + unlikely(err)) { mod_timer(&queue->rx_refill_timer, jiffies + (HZ/10)); return; } -- 2.39.5