From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3152FC55189 for ; Wed, 22 Apr 2020 10:00:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 103322078C for ; Wed, 22 Apr 2020 10:00:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587549624; bh=RXGWWDNqVU5w/HtdHRoEklIc5A5zJOR7dLQpA+nJpVI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=huC4W1JW1pp1Ct38BZiRqzmnW/hWQqy9dDJN3CLpvdKZNOXFJQSwGzFhxkdMTdqIX 1Z8SbWskilVx1MPmIwKMhHCh3XYBaAy5O7IWrIy+BUkem5/O2Qit27BEX2EXhKGOyD nFyAXLDTsz1a/MKsEhTdVWelj4OuHpR3LjMywj8w= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726614AbgDVKAX (ORCPT ); Wed, 22 Apr 2020 06:00:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:47466 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726066AbgDVKAR (ORCPT ); Wed, 22 Apr 2020 06:00:17 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 49E4520776; Wed, 22 Apr 2020 10:00:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587549616; bh=RXGWWDNqVU5w/HtdHRoEklIc5A5zJOR7dLQpA+nJpVI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AKNyEYwdqj8yyhMZY7VG3qQvmCqdVaNU/Ssj+uk2NmXlG9hbV6NV4hV0ahauYA37z j4siQTOi+utCbY7teu4gCWdrg0qvMD+6lvDX64bgNesTnBWe1MWzknw2UAbi9PZkiD hp2LhQnye/aSW83fkI8uEsZ1kvpveTLuahy15RzI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vineeth Remanan Pillai , Boris Ostrovsky , "David S. Miller" , Guenter Roeck Subject: [PATCH 4.4 036/100] xen-netfront: Rework the fix for Rx stall during OOM and network stress Date: Wed, 22 Apr 2020 11:56:06 +0200 Message-Id: <20200422095029.087288097@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200422095022.476101261@linuxfoundation.org> References: <20200422095022.476101261@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vineeth Remanan Pillai 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(-) --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -283,6 +283,7 @@ static void xennet_alloc_rx_buffers(stru { 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(stru 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(stru 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; }