From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.12]) by mail.toke.dk (Postfix) with ESMTPS id A475AAF9D68 for ; Sun, 16 Feb 2025 10:35:24 +0100 (CET) Authentication-Results: mail.toke.dk; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=QqM5Bu5j DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1739698525; x=1771234525; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=1ZNUHtJ1pgOfw/IuS15coOc2ol1V/tTszPLKQRh9oB4=; b=QqM5Bu5jCUUaRZrGoUDMzhPmOLkkbWXChEHZrVvRQdjsSknWPyunYiek HOcOrQTPJ+6XCvgbJt8kLTmhK0Iv6BA4Nt8kTfs7beUckfpdGOtV5I1Zg MPTb+WUptncEgqbUKRrb7y/YkVzDX2a5ozmfHRQXGvP22MG9CEPBzVDAT A3v2qrpDe+ZXySOpfwrvNJSsUV+mXZ1rCTc8chHRaOpMU+Ox6fbDeCJFt AxEJj/46vkkpvons3zI0iv5HgUty7uEVwnpMYgUHsNfvO1lkzyYXWkKR7 LFLxEpmk+JAL3LKs8fVaYd9Vt4qGtW8p22VTVj26l5E3j9gcgR0GU9esh A==; X-CSE-ConnectionGUID: L0gSOOr4RjSjP6yF4rasrQ== X-CSE-MsgGUID: a5IKAFeHTEOUA/nmp2JvwQ== X-IronPort-AV: E=McAfee;i="6700,10204,11346"; a="51812308" X-IronPort-AV: E=Sophos;i="6.13,290,1732608000"; d="scan'208";a="51812308" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Feb 2025 01:35:23 -0800 X-CSE-ConnectionGUID: mQR8umIpTWCfl0YvPa2UiQ== X-CSE-MsgGUID: 7h0fv+32RZ6Lmi3uXnva1g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,224,1728975600"; d="scan'208";a="117999100" Received: from p12ill20yoongsia.png.intel.com ([10.88.227.38]) by fmviesa003.fm.intel.com with ESMTP; 16 Feb 2025 01:35:12 -0800 From: Song Yoong Siang To: "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Willem de Bruijn , Florian Bezdeka , Donald Hunter , Jonathan Corbet , Bjorn Topel , Magnus Karlsson , Maciej Fijalkowski , Jonathan Lemon , Andrew Lunn , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Joe Damato , Stanislav Fomichev , Xuan Zhuo , Mina Almasry , Daniel Jurgens , Song Yoong Siang , Andrii Nakryiko , Eduard Zingerman , Mykola Lysenko , Martin KaFai Lau , Song Liu , Yonghong Song , KP Singh , Hao Luo , Jiri Olsa , Shuah Khan , Alexandre Torgue , Jose Abreu , Maxime Coquelin , Tony Nguyen , Przemek Kitszel , Faizal Rahim , Choong Yong Liang , Bouska Zdenek Date: Sun, 16 Feb 2025 17:34:29 +0800 Message-Id: <20250216093430.957880-5-yoong.siang.song@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250216093430.957880-1-yoong.siang.song@intel.com> References: <20250216093430.957880-1-yoong.siang.song@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: 7T5TVHK7WG6JX6B7INC2CQQXQLEMTR4P X-Message-ID-Hash: 7T5TVHK7WG6JX6B7INC2CQQXQLEMTR4P X-MailFrom: yoong.siang.song@intel.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; emergency; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, intel-wired-lan@lists.osuosl.org, xdp-hints@xdp-project.net X-Mailman-Version: 3.3.10 Precedence: list Subject: [xdp-hints] [PATCH bpf-next v12 4/5] igc: Refactor empty frame insertion for launch time support List-Id: XDP hardware hints design discussion Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Refactor the code for inserting an empty frame into a new function igc_insert_empty_frame(). This change extracts the logic for inserting an empty packet from igc_xmit_frame_ring() into a separate function, allowing it to be reused in future implementations, such as the XDP zero copy transmit function. Remove the igc_desc_unused() checking in igc_init_tx_empty_descriptor() because the number of descriptors needed is guaranteed. Ensure that skb allocation and DMA mapping work for the empty frame, before proceeding to fill in igc_tx_buffer info, context descriptor, and data descriptor. Rate limit the error messages for skb allocation and DMA mapping failures. Update the comment to indicate that the 2 descriptors needed by the empty frame are already taken into consideration in igc_xmit_frame_ring(). Handle the case where the insertion of an empty frame fails and explain the reason behind this handling. Reviewed-by: Faizal Rahim Reviewed-by: Maciej Fijalkowski Signed-off-by: Song Yoong Siang --- drivers/net/ethernet/intel/igc/igc_main.c | 82 ++++++++++++++--------- 1 file changed, 50 insertions(+), 32 deletions(-) diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c index 84307bb7313e..1bfa71545e37 100644 --- a/drivers/net/ethernet/intel/igc/igc_main.c +++ b/drivers/net/ethernet/intel/igc/igc_main.c @@ -1092,7 +1092,8 @@ static int igc_init_empty_frame(struct igc_ring *ring, dma = dma_map_single(ring->dev, skb->data, size, DMA_TO_DEVICE); if (dma_mapping_error(ring->dev, dma)) { - netdev_err_once(ring->netdev, "Failed to map DMA for TX\n"); + net_err_ratelimited("%s: DMA mapping error for empty frame\n", + netdev_name(ring->netdev)); return -ENOMEM; } @@ -1108,20 +1109,12 @@ static int igc_init_empty_frame(struct igc_ring *ring, return 0; } -static int igc_init_tx_empty_descriptor(struct igc_ring *ring, - struct sk_buff *skb, - struct igc_tx_buffer *first) +static void igc_init_tx_empty_descriptor(struct igc_ring *ring, + struct sk_buff *skb, + struct igc_tx_buffer *first) { union igc_adv_tx_desc *desc; u32 cmd_type, olinfo_status; - int err; - - if (!igc_desc_unused(ring)) - return -EBUSY; - - err = igc_init_empty_frame(ring, first, skb); - if (err) - return err; cmd_type = IGC_ADVTXD_DTYP_DATA | IGC_ADVTXD_DCMD_DEXT | IGC_ADVTXD_DCMD_IFCS | IGC_TXD_DCMD | @@ -1140,8 +1133,6 @@ static int igc_init_tx_empty_descriptor(struct igc_ring *ring, ring->next_to_use++; if (ring->next_to_use == ring->count) ring->next_to_use = 0; - - return 0; } #define IGC_EMPTY_FRAME_SIZE 60 @@ -1567,6 +1558,40 @@ static bool igc_request_tx_tstamp(struct igc_adapter *adapter, struct sk_buff *s return false; } +static int igc_insert_empty_frame(struct igc_ring *tx_ring) +{ + struct igc_tx_buffer *empty_info; + struct sk_buff *empty_skb; + void *data; + int ret; + + empty_info = &tx_ring->tx_buffer_info[tx_ring->next_to_use]; + empty_skb = alloc_skb(IGC_EMPTY_FRAME_SIZE, GFP_ATOMIC); + if (unlikely(!empty_skb)) { + net_err_ratelimited("%s: skb alloc error for empty frame\n", + netdev_name(tx_ring->netdev)); + return -ENOMEM; + } + + data = skb_put(empty_skb, IGC_EMPTY_FRAME_SIZE); + memset(data, 0, IGC_EMPTY_FRAME_SIZE); + + /* Prepare DMA mapping and Tx buffer information */ + ret = igc_init_empty_frame(tx_ring, empty_info, empty_skb); + if (unlikely(ret)) { + dev_kfree_skb_any(empty_skb); + return ret; + } + + /* Prepare advanced context descriptor for empty packet */ + igc_tx_ctxtdesc(tx_ring, 0, false, 0, 0, 0); + + /* Prepare advanced data descriptor for empty packet */ + igc_init_tx_empty_descriptor(tx_ring, empty_skb, empty_info); + + return 0; +} + static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb, struct igc_ring *tx_ring) { @@ -1586,6 +1611,7 @@ static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb, * + 1 desc for skb_headlen/IGC_MAX_DATA_PER_TXD, * + 2 desc gap to keep tail from touching head, * + 1 desc for context descriptor, + * + 2 desc for inserting an empty packet for launch time, * otherwise try next time */ for (f = 0; f < skb_shinfo(skb)->nr_frags; f++) @@ -1605,24 +1631,16 @@ static netdev_tx_t igc_xmit_frame_ring(struct sk_buff *skb, launch_time = igc_tx_launchtime(tx_ring, txtime, &first_flag, &insert_empty); if (insert_empty) { - struct igc_tx_buffer *empty_info; - struct sk_buff *empty; - void *data; - - empty_info = &tx_ring->tx_buffer_info[tx_ring->next_to_use]; - empty = alloc_skb(IGC_EMPTY_FRAME_SIZE, GFP_ATOMIC); - if (!empty) - goto done; - - data = skb_put(empty, IGC_EMPTY_FRAME_SIZE); - memset(data, 0, IGC_EMPTY_FRAME_SIZE); - - igc_tx_ctxtdesc(tx_ring, 0, false, 0, 0, 0); - - if (igc_init_tx_empty_descriptor(tx_ring, - empty, - empty_info) < 0) - dev_kfree_skb_any(empty); + /* Reset the launch time if the required empty frame fails to + * be inserted. However, this packet is not dropped, so it + * "dirties" the current Qbv cycle. This ensures that the + * upcoming packet, which is scheduled in the next Qbv cycle, + * does not require an empty frame. This way, the launch time + * continues to function correctly despite the current failure + * to insert the empty frame. + */ + if (igc_insert_empty_frame(tx_ring)) + launch_time = 0; } done: -- 2.34.1