From patchwork Mon Sep 9 16:55:38 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Kirsher, Jeffrey T" X-Patchwork-Id: 1159874 X-Patchwork-Delegate: jeffrey.t.kirsher@intel.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=osuosl.org (client-ip=140.211.166.137; helo=fraxinus.osuosl.org; envelope-from=intel-wired-lan-bounces@osuosl.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=intel.com Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 46RvTK6gC7z9sNf for ; Tue, 10 Sep 2019 02:55:44 +1000 (AEST) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id B63C5858BA; Mon, 9 Sep 2019 16:55:42 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id w7p2RlWfD-_K; Mon, 9 Sep 2019 16:55:41 +0000 (UTC) Received: from ash.osuosl.org (ash.osuosl.org [140.211.166.34]) by fraxinus.osuosl.org (Postfix) with ESMTP id AE78D85886; Mon, 9 Sep 2019 16:55:41 +0000 (UTC) X-Original-To: intel-wired-lan@lists.osuosl.org Delivered-To: intel-wired-lan@lists.osuosl.org Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by ash.osuosl.org (Postfix) with ESMTP id B72751BF3A7 for ; Mon, 9 Sep 2019 16:55:40 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id AF3D285886 for ; Mon, 9 Sep 2019 16:55:40 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id XZhQU8Cjka5m for ; Mon, 9 Sep 2019 16:55:40 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by fraxinus.osuosl.org (Postfix) with ESMTPS id 314B885876 for ; Mon, 9 Sep 2019 16:55:40 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 09 Sep 2019 09:55:39 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,486,1559545200"; d="scan'208";a="178406141" Received: from jtkirshe-desk1.jf.intel.com ([134.134.177.96]) by orsmga008.jf.intel.com with ESMTP; 09 Sep 2019 09:55:39 -0700 From: Jeff Kirsher To: intel-wired-lan@lists.osuosl.org Date: Mon, 9 Sep 2019 09:55:38 -0700 Message-Id: <20190909165538.8125-1-jeffrey.t.kirsher@intel.com> X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 Subject: [Intel-wired-lan] [PATCH v2] i40e: fix potential RX buffer starvation for AF_XDP X-BeenThere: intel-wired-lan@osuosl.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Wired Ethernet Linux Kernel Driver Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Magnus Karlsson Errors-To: intel-wired-lan-bounces@osuosl.org Sender: "Intel-wired-lan" From: Magnus Karlsson When the RX rings are created they are also populated with buffers so that packets can be received. Usually these are kernel buffers, but for AF_XDP in zero-copy mode, these are user-space buffers and in this case the application might not have sent down any buffers to the driver at this point. And if no buffers are allocated at ring creation time, no packets can be received and no interrupts will be generated so the NAPI poll function that allocates buffers to the rings will never get executed. To rectify this, we kick the NAPI context of any queue with an attached AF_XDP zero-copy socket in two places in the code. Once after an XDP program has loaded and once after the umem is registered. This take care of both cases: XDP program gets loaded first then AF_XDP socket is created, and the reverse, AF_XDP socket is created first, then XDP program is loaded. Fixes: 0a714186d3c0 ("i40e: add AF_XDP zero-copy Rx support") Signed-off-by: Magnus Karlsson Tested-by: Andrew Bowers --- drivers/net/ethernet/intel/i40e/i40e_xsk.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c index 0373bc6c7e61..feb5bd54d840 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c @@ -157,6 +157,11 @@ static int i40e_xsk_umem_disable(struct i40e_vsi *vsi, u16 qid) err = i40e_queue_pair_enable(vsi, qid); if (err) return err; + + /* Kick start the NAPI context so that receiving will start */ + err = i40e_xsk_wakeup(vsi->netdev, qid, XDP_WAKEUP_RX); + if (err) + return err; } return 0;