From patchwork Wed Dec 13 11:28:31 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Lobakin X-Patchwork-Id: 13490747 X-Patchwork-Delegate: kuba@kernel.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="QE8Z4+zg" Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F4110189; Wed, 13 Dec 2023 03:31:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1702467072; x=1734003072; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=4DiC3NQAzAt61dhtsmHMEP21ETiBi5sJsIY8ZwsJnDA=; b=QE8Z4+zgyRLqskrd5O4I1HZiHjyVdOcXZ5QBFW2mi0UA4Zoj6CpBXXWP e76PEtPXQ76GspJ9Pk+NaRREAdzXSq4/Xkwf+9Q+2wM3hhp51lvVWNGo2 aQ4RJDrnUwyeOKlEJffikr48Id/QhQ6yrTO7oTo6U9snTxssP6Fc/mx8p aIeCWCjYh417YjmWgV+b3Erm4fZ9g6RjDtqUVqgrZ/abxxP58ZiULwaLK q1uCwUL3n1Y8IyJ2XPdCbpw+WSBBu13hm4tApSfKcnbEkJdH1WTZoC7o0 ZLW92KWXfFWNdw7jMlO7gfZFGxq4BDWOQbnE2FecoQ3Zqn3J6sHy25r9A g==; X-IronPort-AV: E=McAfee;i="6600,9927,10922"; a="375104034" X-IronPort-AV: E=Sophos;i="6.04,272,1695711600"; d="scan'208";a="375104034" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Dec 2023 03:31:12 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10922"; a="844279536" X-IronPort-AV: E=Sophos;i="6.04,272,1695711600"; d="scan'208";a="844279536" Received: from newjersey.igk.intel.com ([10.102.20.203]) by fmsmga004.fm.intel.com with ESMTP; 13 Dec 2023 03:31:08 -0800 From: Alexander Lobakin To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Alexander Lobakin , Maciej Fijalkowski , Michal Kubiak , Larysa Zaremba , Alexander Duyck , Yunsheng Lin , David Christensen , Jesper Dangaard Brouer , Ilias Apalodimas , Paul Menzel , netdev@vger.kernel.org, intel-wired-lan@lists.osuosl.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v7 08/12] libie: add Rx buffer management (via Page Pool) Date: Wed, 13 Dec 2023 12:28:31 +0100 Message-ID: <20231213112835.2262651-9-aleksander.lobakin@intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231213112835.2262651-1-aleksander.lobakin@intel.com> References: <20231213112835.2262651-1-aleksander.lobakin@intel.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org Add a couple intuitive helpers to hide Rx buffer implementation details in the library and not multiplicate it between drivers. The settings are optimized for Intel hardware, but nothing really HW-specific here. Use the new page_pool_dev_alloc() to dynamically switch between split-page and full-page modes depending on MTU, page size, required headroom etc. For example, on x86_64 with the default driver settings each page is shared between 2 buffers. Turning on XDP (not in this series) -> increasing headroom requirement pushes truesize out of 2048 boundary, leading to that each buffer starts getting a full page. The "ceiling" limit is %PAGE_SIZE, as only order-0 pages are used to avoid compound overhead. For the above architecture, this means maximum linear frame size of 3712 w/o XDP. Not that &libie_buf_queue is not a complete queue/ring structure for now, rather a shim, but eventually the libie-enabled drivers will move to it, with iavf being the first one. Signed-off-by: Alexander Lobakin --- drivers/net/ethernet/intel/libie/Kconfig | 1 + drivers/net/ethernet/intel/libie/rx.c | 69 ++++++++++++ include/linux/net/intel/libie/rx.h | 133 ++++++++++++++++++++++- 3 files changed, 202 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/libie/Kconfig b/drivers/net/ethernet/intel/libie/Kconfig index 1eda4a5faa5a..6e0162fb94d2 100644 --- a/drivers/net/ethernet/intel/libie/Kconfig +++ b/drivers/net/ethernet/intel/libie/Kconfig @@ -3,6 +3,7 @@ config LIBIE tristate + select PAGE_POOL help libie (Intel Ethernet library) is a common library containing routines shared between several Intel Ethernet drivers. diff --git a/drivers/net/ethernet/intel/libie/rx.c b/drivers/net/ethernet/intel/libie/rx.c index f503476d8eef..04037973cd87 100644 --- a/drivers/net/ethernet/intel/libie/rx.c +++ b/drivers/net/ethernet/intel/libie/rx.c @@ -3,6 +3,75 @@ #include +/* Rx buffer management */ + +/** + * libie_rx_hw_len - get the actual buffer size to be passed to HW + * @pp: &page_pool_params of the netdev to calculate the size for + * + * Return: HW-writeable length per one buffer to pass it to the HW accounting: + * MTU the @dev has, HW required alignment, minimum and maximum allowed values, + * and system's page size. + */ +static u32 libie_rx_hw_len(const struct page_pool_params *pp) +{ + u32 len; + + len = READ_ONCE(pp->netdev->mtu) + LIBIE_RX_LL_LEN; + len = ALIGN(len, LIBIE_RX_BUF_LEN_ALIGN); + len = clamp(len, LIBIE_MIN_RX_BUF_LEN, pp->max_len); + + return len; +} + +/** + * libie_rx_page_pool_create - create a PP with the default libie settings + * @bq: buffer queue struct to fill + * @napi: &napi_struct covering this PP (no usage outside its poll loops) + * + * Return: 0 on success, -errno on failure. + */ +int libie_rx_page_pool_create(struct libie_buf_queue *bq, + struct napi_struct *napi) +{ + struct page_pool_params pp = { + .flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV, + .order = LIBIE_RX_PAGE_ORDER, + .pool_size = bq->count, + .nid = NUMA_NO_NODE, + .dev = napi->dev->dev.parent, + .netdev = napi->dev, + .napi = napi, + .dma_dir = DMA_FROM_DEVICE, + .offset = LIBIE_SKB_HEADROOM, + }; + + /* HW-writeable / syncable length per one page */ + pp.max_len = LIBIE_RX_BUF_LEN(pp.offset); + + /* HW-writeable length per buffer */ + bq->rx_buf_len = libie_rx_hw_len(&pp); + /* Buffer size to allocate */ + bq->truesize = roundup_pow_of_two(SKB_HEAD_ALIGN(pp.offset + + bq->rx_buf_len)); + + bq->pp = page_pool_create(&pp); + + return PTR_ERR_OR_ZERO(bq->pp); +} +EXPORT_SYMBOL_NS_GPL(libie_rx_page_pool_create, LIBIE); + +/** + * libie_rx_page_pool_destroy - destroy a &page_pool created by libie + * @bq: buffer queue to process + */ +void libie_rx_page_pool_destroy(struct libie_buf_queue *bq) +{ + page_pool_destroy(bq->pp); + bq->pp = NULL; +} +EXPORT_SYMBOL_NS_GPL(libie_rx_page_pool_destroy, LIBIE); + /* O(1) converting i40e/ice/iavf's 8/10-bit hardware packet type to a parsed * bitfield struct. */ diff --git a/include/linux/net/intel/libie/rx.h b/include/linux/net/intel/libie/rx.h index 55263930aa99..71bc9a1a9856 100644 --- a/include/linux/net/intel/libie/rx.h +++ b/include/linux/net/intel/libie/rx.h @@ -4,7 +4,138 @@ #ifndef __LIBIE_RX_H #define __LIBIE_RX_H -#include +#include +#include + +/* Rx MTU/buffer/truesize helpers. Mostly pure software-side; HW-defined values + * are valid for all Intel HW. + */ + +/* Space reserved in front of each frame */ +#define LIBIE_SKB_HEADROOM (NET_SKB_PAD + NET_IP_ALIGN) +/* Maximum headroom to calculate max MTU below */ +#define LIBIE_MAX_HEADROOM LIBIE_SKB_HEADROOM +/* Link layer / L2 overhead: Ethernet, 2 VLAN tags (C + S), FCS */ +#define LIBIE_RX_LL_LEN (ETH_HLEN + 2 * VLAN_HLEN + ETH_FCS_LEN) + +/* Always use order-0 pages */ +#define LIBIE_RX_PAGE_ORDER 0 +/* Rx buffer size config is a multiple of 128 */ +#define LIBIE_RX_BUF_LEN_ALIGN 128 +/* HW-writeable space in one buffer: truesize - headroom/tailroom, + * HW-aligned + */ +#define __LIBIE_RX_BUF_LEN(hr) \ + ALIGN_DOWN(SKB_MAX_ORDER(hr, LIBIE_RX_PAGE_ORDER), \ + LIBIE_RX_BUF_LEN_ALIGN) +/* The smallest and largest size for a single descriptor as per HW */ +#define LIBIE_MIN_RX_BUF_LEN 1024U +#define LIBIE_MAX_RX_BUF_LEN 9728U +/* "True" HW-writeable space: minimum from SW and HW values */ +#define LIBIE_RX_BUF_LEN(hr) min_t(u32, __LIBIE_RX_BUF_LEN(hr), \ + LIBIE_MAX_RX_BUF_LEN) + +/* The maximum frame size as per HW (S/G) */ +#define __LIBIE_MAX_RX_FRM_LEN 16382U +/* ATST, HW can chain up to 5 Rx descriptors */ +#define LIBIE_MAX_RX_FRM_LEN(hr) \ + min_t(u32, __LIBIE_MAX_RX_FRM_LEN, LIBIE_RX_BUF_LEN(hr) * 5) +/* Maximum frame size minus LL overhead */ +#define LIBIE_MAX_MTU \ + (LIBIE_MAX_RX_FRM_LEN(LIBIE_MAX_HEADROOM) - LIBIE_RX_LL_LEN) + +/* Rx buffer management */ + +/** + * struct libie_rx_buffer - structure representing an Rx buffer + * @page: page holding the buffer + * @offset: offset from the page start (to the headroom) + * @truesize: total space occupied by the buffer (w/ headroom and tailroom) + * + * Depending on the MTU, API switches between one-page-per-frame and shared + * page model (to conserve memory on bigger-page platforms). In case of the + * former, @offset is always 0 and @truesize is always ```PAGE_SIZE```. + */ +struct libie_rx_buffer { + struct page *page; + u32 offset; + u32 truesize; +}; + +/** + * struct libie_buf_queue - structure representing a buffer queue + * @pp: &page_pool for buffer management + * @rx_bi: array of Rx buffers + * @truesize: size to allocate per buffer, w/overhead + * @count: number of descriptors/buffers the queue has + * @rx_buf_len: HW-writeable length per each buffer + */ +struct libie_buf_queue { + struct page_pool *pp; + struct libie_rx_buffer *rx_bi; + + u32 truesize; + u32 count; + + /* Cold fields */ + u32 rx_buf_len; +}; + +int libie_rx_page_pool_create(struct libie_buf_queue *bq, + struct napi_struct *napi); +void libie_rx_page_pool_destroy(struct libie_buf_queue *bq); + +/** + * libie_rx_alloc - allocate a new Rx buffer + * @bq: buffer queue to allocate for + * @i: index of the buffer within the queue + * + * Return: DMA address to be passed to HW for Rx on successful allocation, + * ```DMA_MAPPING_ERROR``` otherwise. + */ +static inline dma_addr_t libie_rx_alloc(const struct libie_buf_queue *bq, + u32 i) +{ + struct libie_rx_buffer *buf = &bq->rx_bi[i]; + + buf->truesize = bq->truesize; + buf->page = page_pool_dev_alloc(bq->pp, &buf->offset, &buf->truesize); + if (unlikely(!buf->page)) + return DMA_MAPPING_ERROR; + + return page_pool_get_dma_addr(buf->page) + buf->offset + + bq->pp->p.offset; +} + +/** + * libie_rx_sync_for_cpu - synchronize or recycle buffer post DMA + * @buf: buffer to process + * @len: frame length from the descriptor + * + * Process the buffer after it's written by HW. The regular path is to + * synchronize DMA for CPU, but in case of no data it will be immediately + * recycled back to its PP. + * + * Return: true when there's data to process, false otherwise. + */ +static inline bool libie_rx_sync_for_cpu(const struct libie_rx_buffer *buf, + u32 len) +{ + struct page *page = buf->page; + + /* Very rare, but possible case. The most common reason: + * the last fragment contained FCS only, which was then + * stripped by the HW. + */ + if (unlikely(!len)) { + page_pool_recycle_direct(page->pp, page); + return false; + } + + page_pool_dma_sync_for_cpu(page->pp, page, buf->offset, len); + + return true; +} /* O(1) converting i40e/ice/iavf's 8/10-bit hardware packet type to a parsed * bitfield struct.