From 21f79ae43fd2d498847ff82161027a62a1269926 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: Eduardo Valentin Signed-off-by: Greg Kroah-Hartman --- drivers/net/xen-netfront.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) (limited to 'drivers/net') diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 599cf5090030..cd442e46afb4 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; } -- cgit v1.2.3