From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755178AbdBGS7L (ORCPT ); Tue, 7 Feb 2017 13:59:11 -0500 Received: from smtp-fw-2101.amazon.com ([72.21.196.25]:7634 "EHLO smtp-fw-2101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754530AbdBGS7J (ORCPT ); Tue, 7 Feb 2017 13:59:09 -0500 X-IronPort-AV: E=Sophos;i="5.33,346,1477958400"; d="scan'208";a="639082281" From: Vineeth Remanan Pillai To: , , , , CC: Vineeth Remanan Pillai , , , Subject: [PATCH] xen-netfront: Rework the fix for Rx stall during OOM and network stress Date: Tue, 7 Feb 2017 18:59:01 +0000 Message-ID: <1486493941-15696-1-git-send-email-vineethp@amazon.com> X-Mailer: git-send-email 2.1.2.AMZN MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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 8315fe7..9dba697 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; } -- 2.1.2.AMZN