From 3999e00756a46a74f5eef404a75a9f8fce5c18a3 Mon Sep 17 00:00:00 2001 From: Vineeth Remanan Pillai Date: Tue, 7 Feb 2017 18:59:01 +0000 Subject: xen-netfront: Rework the fix for Rx stall during OOM and network stress commit 538d92912d3190a1dd809233a0d57277459f37b2 upstream. The commit 90c311b0eeea ("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: 90c311b0eeea (xen-netfront: Fix Rx stall during network stress and OOM) Reported-by: Boris Ostrovsky Reviewed-by: Boris Ostrovsky Signed-off-by: David S. Miller Cc: Guenter Roeck Signed-off-by: Greg Kroah-Hartman --- 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 e99a07d5fda7..02b6a6c10840 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -283,6 +283,7 @@ 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; @@ -297,8 +298,10 @@ 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); @@ -322,8 +325,13 @@ 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; } -- cgit v1.2.3