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[5.94.253.60]) by smtp.gmail.com with ESMTPSA id b12sm14577136eds.23.2021.05.11.06.33.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 May 2021 06:33:15 -0700 (PDT) From: Matteo Croce To: netdev@vger.kernel.org, linux-mm@kvack.org Cc: Ayush Sawal , Vinay Kumar Yadav , Rohit Maheshwari , "David S. Miller" , Jakub Kicinski , Thomas Petazzoni , Marcin Wojtas , Russell King , Mirko Lindner , Stephen Hemminger , Tariq Toukan , Jesper Dangaard Brouer , Ilias Apalodimas , Alexei Starovoitov , Daniel Borkmann , John Fastabend , Boris Pismenny , Arnd Bergmann , Andrew Morton , "Peter Zijlstra (Intel)" , Vlastimil Babka , Yu Zhao , Will Deacon , Michel Lespinasse , Fenghua Yu , Roman Gushchin , Hugh Dickins , Peter Xu , Jason Gunthorpe , Jonathan Lemon , Alexander Lobakin , Cong Wang , wenxu , Kevin Hao , Jakub Sitnicki , Marco Elver , Willem de Bruijn , Miaohe Lin , Yunsheng Lin , Guillaume Nault , linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, bpf@vger.kernel.org, Matthew Wilcox , Eric Dumazet , David Ahern , Lorenzo Bianconi , Saeed Mahameed , Andrew Lunn , Paolo Abeni , Sven Auhagen Subject: [PATCH net-next v4 2/4] page_pool: Allow drivers to hint on SKB recycling Date: Tue, 11 May 2021 15:31:16 +0200 Message-Id: <20210511133118.15012-3-mcroce@linux.microsoft.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210511133118.15012-1-mcroce@linux.microsoft.com> References: <20210511133118.15012-1-mcroce@linux.microsoft.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Ilias Apalodimas Up to now several high speed NICs have custom mechanisms of recycling the allocated memory they use for their payloads. Our page_pool API already has recycling capabilities that are always used when we are running in 'XDP mode'. So let's tweak the API and the kernel network stack slightly and allow the recycling to happen even during the standard operation. The API doesn't take into account 'split page' policies used by those drivers currently, but can be extended once we have users for that. The idea is to be able to intercept the packet on skb_release_data(). If it's a buffer coming from our page_pool API recycle it back to the pool for further usage or just release the packet entirely. To achieve that we introduce a bit in struct sk_buff (pp_recycle:1) and store the page_pool pointer in page->private. Storing the information in page->private allows us to recycle both SKBs and their fragments. The SKB bit is needed for a couple of reasons. First of all in an effort to affect the free path as less as possible, reading a single bit, is better that trying to derive identical information for the page stored data. Moreover page->private is used by skb_copy_ubufs. We do have a special mark in the page, that won't allow this to happen, but again deciding without having to read the entire page is preferable. The driver has to take care of the sync operations on it's own during the buffer recycling since the buffer is, after opting-in to the recycling, never unmapped. Since the gain on the drivers depends on the architecture, we are not enabling recycling by default if the page_pool API is used on a driver. In order to enable recycling the driver must call skb_mark_for_recycle() to store the information we need for recycling in page->private and enabling the recycling bit, or page_pool_store_mem_info() for a fragment. Since we added an extra argument on __skb_frag_unref() to handle recycling, update the current users of the function with that. Co-developed-by: Jesper Dangaard Brouer Co-developed-by: Matteo Croce Signed-off-by: Ilias Apalodimas Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Matteo Croce --- drivers/net/ethernet/marvell/sky2.c | 2 +- drivers/net/ethernet/mellanox/mlx4/en_rx.c | 2 +- include/linux/skbuff.h | 34 ++++++++++++++++++---- include/net/page_pool.h | 9 ++++++ net/core/page_pool.c | 23 +++++++++++++++ net/core/skbuff.c | 20 +++++++++++-- net/tls/tls_device.c | 2 +- 7 files changed, 82 insertions(+), 10 deletions(-) -- 2.31.1 diff --git a/drivers/net/ethernet/marvell/sky2.c b/drivers/net/ethernet/marvell/sky2.c index 222c32367b2c..aa0cde1dc5c0 100644 --- a/drivers/net/ethernet/marvell/sky2.c +++ b/drivers/net/ethernet/marvell/sky2.c @@ -2503,7 +2503,7 @@ static void skb_put_frags(struct sk_buff *skb, unsigned int hdr_space, if (length == 0) { /* don't need this page */ - __skb_frag_unref(frag); + __skb_frag_unref(frag, false); --skb_shinfo(skb)->nr_frags; } else { size = min(length, (unsigned) PAGE_SIZE); diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c index e35e4d7ef4d1..cea62b8f554c 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c @@ -526,7 +526,7 @@ static int mlx4_en_complete_rx_desc(struct mlx4_en_priv *priv, fail: while (nr > 0) { nr--; - __skb_frag_unref(skb_shinfo(skb)->frags + nr); + __skb_frag_unref(skb_shinfo(skb)->frags + nr, false); } return 0; } diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index dbf820a50a39..1a2ce52c29f9 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -40,6 +40,9 @@ #if IS_ENABLED(CONFIG_NF_CONNTRACK) #include #endif +#if IS_BUILTIN(CONFIG_PAGE_POOL) +#include +#endif /* The interface for checksum offload between the stack and networking drivers * is as follows... @@ -667,6 +670,8 @@ typedef unsigned char *sk_buff_data_t; * @head_frag: skb was allocated from page fragments, * not allocated by kmalloc() or vmalloc(). * @pfmemalloc: skbuff was allocated from PFMEMALLOC reserves + * @pp_recycle: mark the packet for recycling instead of freeing (implies + * page_pool support on driver) * @active_extensions: active extensions (skb_ext_id types) * @ndisc_nodetype: router type (from link layer) * @ooo_okay: allow the mapping of a socket to a queue to be changed @@ -791,10 +796,12 @@ struct sk_buff { fclone:2, peeked:1, head_frag:1, - pfmemalloc:1; + pfmemalloc:1, + pp_recycle:1; /* page_pool recycle indicator */ #ifdef CONFIG_SKB_EXTENSIONS __u8 active_extensions; #endif + /* fields enclosed in headers_start/headers_end are copied * using a single memcpy() in __copy_skb_header() */ @@ -3081,12 +3088,20 @@ static inline void skb_frag_ref(struct sk_buff *skb, int f) /** * __skb_frag_unref - release a reference on a paged fragment. * @frag: the paged fragment + * @recycle: recycle the page if allocated via page_pool * - * Releases a reference on the paged fragment @frag. + * Releases a reference on the paged fragment @frag + * or recycles the page via the page_pool API. */ -static inline void __skb_frag_unref(skb_frag_t *frag) +static inline void __skb_frag_unref(skb_frag_t *frag, bool recycle) { - put_page(skb_frag_page(frag)); + struct page *page = skb_frag_page(frag); + +#if IS_BUILTIN(CONFIG_PAGE_POOL) + if (recycle && page_pool_return_skb_page(page_address(page))) + return; +#endif + put_page(page); } /** @@ -3098,7 +3113,7 @@ static inline void __skb_frag_unref(skb_frag_t *frag) */ static inline void skb_frag_unref(struct sk_buff *skb, int f) { - __skb_frag_unref(&skb_shinfo(skb)->frags[f]); + __skb_frag_unref(&skb_shinfo(skb)->frags[f], skb->pp_recycle); } /** @@ -4697,5 +4712,14 @@ static inline u64 skb_get_kcov_handle(struct sk_buff *skb) #endif } +#if IS_BUILTIN(CONFIG_PAGE_POOL) +static inline void skb_mark_for_recycle(struct sk_buff *skb, struct page *page, + struct page_pool *pp) +{ + skb->pp_recycle = 1; + page_pool_store_mem_info(page, pp); +} +#endif + #endif /* __KERNEL__ */ #endif /* _LINUX_SKBUFF_H */ diff --git a/include/net/page_pool.h b/include/net/page_pool.h index 9814e36becc1..b34b8b128206 100644 --- a/include/net/page_pool.h +++ b/include/net/page_pool.h @@ -148,6 +148,8 @@ inline enum dma_data_direction page_pool_get_dma_dir(struct page_pool *pool) return pool->p.dma_dir; } +bool page_pool_return_skb_page(void *data); + struct page_pool *page_pool_create(const struct page_pool_params *params); #ifdef CONFIG_PAGE_POOL @@ -253,4 +255,11 @@ static inline void page_pool_ring_unlock(struct page_pool *pool) spin_unlock_bh(&pool->ring.producer_lock); } +/* Store mem_info on struct page and use it while recycling skb frags */ +static inline +void page_pool_store_mem_info(struct page *page, struct page_pool *pp) +{ + set_page_private(page, (unsigned long)pp); +} + #endif /* _NET_PAGE_POOL_H */ diff --git a/net/core/page_pool.c b/net/core/page_pool.c index 2e5e2b8c3a02..52e4f16b5e92 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -626,3 +626,26 @@ void page_pool_update_nid(struct page_pool *pool, int new_nid) } } EXPORT_SYMBOL(page_pool_update_nid); + +bool page_pool_return_skb_page(void *data) +{ + struct page_pool *pp; + struct page *page; + + page = virt_to_head_page(data); + if (unlikely(page->signature != PP_SIGNATURE)) + return false; + + pp = (struct page_pool *)page_private(page); + + /* Driver set this to memory recycling info. Reset it on recycle. + * This will *not* work for NIC using a split-page memory model. + * The page will be returned to the pool here regardless of the + * 'flipped' fragment being in use or not. + */ + set_page_private(page, 0); + page_pool_put_full_page(pp, virt_to_head_page(data), false); + + return true; +} +EXPORT_SYMBOL(page_pool_return_skb_page); diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 3ad22870298c..dc4a5c56b8dc 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -70,6 +70,9 @@ #include #include #include +#if IS_BUILTIN(CONFIG_PAGE_POOL) +#include +#endif #include #include @@ -645,6 +648,11 @@ static void skb_free_head(struct sk_buff *skb) { unsigned char *head = skb->head; +#if IS_BUILTIN(CONFIG_PAGE_POOL) + if (skb->pp_recycle && page_pool_return_skb_page(head)) + return; +#endif + if (skb->head_frag) skb_free_frag(head); else @@ -664,7 +672,7 @@ static void skb_release_data(struct sk_buff *skb) skb_zcopy_clear(skb, true); for (i = 0; i < shinfo->nr_frags; i++) - __skb_frag_unref(&shinfo->frags[i]); + __skb_frag_unref(&shinfo->frags[i], skb->pp_recycle); if (shinfo->frag_list) kfree_skb_list(shinfo->frag_list); @@ -1046,6 +1054,7 @@ static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb) n->nohdr = 0; n->peeked = 0; C(pfmemalloc); + C(pp_recycle); n->destructor = NULL; C(tail); C(end); @@ -3495,7 +3504,7 @@ int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen) fragto = &skb_shinfo(tgt)->frags[merge]; skb_frag_size_add(fragto, skb_frag_size(fragfrom)); - __skb_frag_unref(fragfrom); + __skb_frag_unref(fragfrom, skb->pp_recycle); } /* Reposition in the original skb */ @@ -5285,6 +5294,13 @@ bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from, if (skb_cloned(to)) return false; + /* We can't coalesce skb that are allocated from slab and page_pool + * The recycle mark is on the skb, so that might end up trying to + * recycle slab allocated skb->head + */ + if (to->pp_recycle != from->pp_recycle) + return false; + if (len <= skb_tailroom(to)) { if (len) BUG_ON(skb_copy_bits(from, 0, skb_put(to, len), len)); diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c index 76a6f8c2eec4..ad11db2c4f63 100644 --- a/net/tls/tls_device.c +++ b/net/tls/tls_device.c @@ -127,7 +127,7 @@ static void destroy_record(struct tls_record_info *record) int i; for (i = 0; i < record->num_frags; i++) - __skb_frag_unref(&record->frags[i]); + __skb_frag_unref(&record->frags[i], false); kfree(record); } From patchwork Tue May 11 13:31:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matteo Croce X-Patchwork-Id: 434732 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 0A9C6C43461 for ; Tue, 11 May 2021 13:34:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DADBC61621 for ; Tue, 11 May 2021 13:34:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231670AbhEKNfZ (ORCPT ); Tue, 11 May 2021 09:35:25 -0400 Received: from mail-ed1-f51.google.com ([209.85.208.51]:37499 "EHLO mail-ed1-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231440AbhEKNfV (ORCPT ); Tue, 11 May 2021 09:35:21 -0400 Received: by mail-ed1-f51.google.com with SMTP id f1so652377edt.4; Tue, 11 May 2021 06:34:12 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=opbCv80kZO0WR00E8CvyXu7JXQ2Kf6zwvEyZ//vM1Tw=; b=a0tLJmbXFy2Jbh0m0MsbqG+TNDnpXzBLj2kWXKUIvobDlq1Kc6K/osYtePuSiat5lp CPEhiUquHVj9JagWjBABWdaPsY4gSWm6+zEZD89qYkNlRCGNfIDUmpqbVwVLaLIqSw+8 K4evr6SJHgNaNSvY5ujMypXSpphnglNUKlHxD+b97Xm9ZNctMBIuX5djj1vDLO8NaIn6 /V2ZKuw2/Q+347loXL2TVZVhIWRJa1UgBwWnwb383tOzLx3H5YifVnLlljhw+D01h71r 8Pp+XrMbm0XDBQ3pZIWgjLSuC3EHGDjfRvNLAmhF37CYyI+JHnrJ1RFaSPA7zz8VvhSH uoYA== X-Gm-Message-State: AOAM530Q+QmPruUx3WnukvoDPlj66fVQu1npHSgOldCunZu2mIjDb2dG FVWXEdsb4tbxDkCj0XUpHZZJjX6eXq2lBIni X-Google-Smtp-Source: ABdhPJxFON1iLvgj/qc5/xaXt8z19zepipzFxfFB7xkn4XGfCltkU60ur9IrBl/dtWY53DcWuTjY1A== X-Received: by 2002:aa7:d950:: with SMTP id l16mr36092015eds.374.1620740052002; Tue, 11 May 2021 06:34:12 -0700 (PDT) Received: from msft-t490s.teknoraver.net (net-5-94-253-60.cust.vodafonedsl.it. [5.94.253.60]) by smtp.gmail.com with ESMTPSA id b12sm14577136eds.23.2021.05.11.06.34.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 May 2021 06:34:11 -0700 (PDT) From: Matteo Croce To: netdev@vger.kernel.org, linux-mm@kvack.org Cc: Ayush Sawal , Vinay Kumar Yadav , Rohit Maheshwari , "David S. Miller" , Jakub Kicinski , Thomas Petazzoni , Marcin Wojtas , Russell King , Mirko Lindner , Stephen Hemminger , Tariq Toukan , Jesper Dangaard Brouer , Ilias Apalodimas , Alexei Starovoitov , Daniel Borkmann , John Fastabend , Boris Pismenny , Arnd Bergmann , Andrew Morton , "Peter Zijlstra (Intel)" , Vlastimil Babka , Yu Zhao , Will Deacon , Michel Lespinasse , Fenghua Yu , Roman Gushchin , Hugh Dickins , Peter Xu , Jason Gunthorpe , Jonathan Lemon , Alexander Lobakin , Cong Wang , wenxu , Kevin Hao , Jakub Sitnicki , Marco Elver , Willem de Bruijn , Miaohe Lin , Yunsheng Lin , Guillaume Nault , linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, bpf@vger.kernel.org, Matthew Wilcox , Eric Dumazet , David Ahern , Lorenzo Bianconi , Saeed Mahameed , Andrew Lunn , Paolo Abeni , Sven Auhagen Subject: [PATCH net-next v4 4/4] mvneta: recycle buffers Date: Tue, 11 May 2021 15:31:18 +0200 Message-Id: <20210511133118.15012-5-mcroce@linux.microsoft.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210511133118.15012-1-mcroce@linux.microsoft.com> References: <20210511133118.15012-1-mcroce@linux.microsoft.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Matteo Croce Use the new recycling API for page_pool. In a drop rate test, the packet rate increased di 10%, from 269 Kpps to 296 Kpps. perf top on a stock system shows: Overhead Shared Object Symbol 21.78% [kernel] [k] __pi___inval_dcache_area 21.66% [mvneta] [k] mvneta_rx_swbm 7.00% [kernel] [k] kmem_cache_alloc 6.05% [kernel] [k] eth_type_trans 4.44% [kernel] [k] kmem_cache_free.part.0 3.80% [kernel] [k] __netif_receive_skb_core 3.68% [kernel] [k] dev_gro_receive 3.65% [kernel] [k] get_page_from_freelist 3.43% [kernel] [k] page_pool_release_page 3.35% [kernel] [k] free_unref_page And this is the same output with recycling enabled: Overhead Shared Object Symbol 24.10% [kernel] [k] __pi___inval_dcache_area 23.02% [mvneta] [k] mvneta_rx_swbm 7.19% [kernel] [k] kmem_cache_alloc 6.50% [kernel] [k] eth_type_trans 4.93% [kernel] [k] __netif_receive_skb_core 4.77% [kernel] [k] kmem_cache_free.part.0 3.93% [kernel] [k] dev_gro_receive 3.03% [kernel] [k] build_skb 2.91% [kernel] [k] page_pool_put_page 2.85% [kernel] [k] __xdp_return The test was done with mausezahn on the TX side with 64 byte raw ethernet frames. Signed-off-by: Matteo Croce --- drivers/net/ethernet/marvell/mvneta.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c index 7d5cd9bc6c99..6d2f8dce4900 100644 --- a/drivers/net/ethernet/marvell/mvneta.c +++ b/drivers/net/ethernet/marvell/mvneta.c @@ -2320,7 +2320,7 @@ mvneta_swbm_add_rx_fragment(struct mvneta_port *pp, } static struct sk_buff * -mvneta_swbm_build_skb(struct mvneta_port *pp, struct mvneta_rx_queue *rxq, +mvneta_swbm_build_skb(struct mvneta_port *pp, struct page_pool *pool, struct xdp_buff *xdp, u32 desc_status) { struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp); @@ -2331,7 +2331,7 @@ mvneta_swbm_build_skb(struct mvneta_port *pp, struct mvneta_rx_queue *rxq, if (!skb) return ERR_PTR(-ENOMEM); - page_pool_release_page(rxq->page_pool, virt_to_page(xdp->data)); + skb_mark_for_recycle(skb, virt_to_page(xdp->data), pool); skb_reserve(skb, xdp->data - xdp->data_hard_start); skb_put(skb, xdp->data_end - xdp->data); @@ -2343,7 +2343,10 @@ mvneta_swbm_build_skb(struct mvneta_port *pp, struct mvneta_rx_queue *rxq, skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, skb_frag_page(frag), skb_frag_off(frag), skb_frag_size(frag), PAGE_SIZE); - page_pool_release_page(rxq->page_pool, skb_frag_page(frag)); + /* We don't need to reset pp_recycle here. It's already set, so + * just mark fragments for recycling. + */ + page_pool_store_mem_info(skb_frag_page(frag), pool); } return skb; @@ -2425,7 +2428,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi, mvneta_run_xdp(pp, rxq, xdp_prog, &xdp_buf, frame_sz, &ps)) goto next; - skb = mvneta_swbm_build_skb(pp, rxq, &xdp_buf, desc_status); + skb = mvneta_swbm_build_skb(pp, pp, &xdp_buf, desc_status); if (IS_ERR(skb)) { struct mvneta_pcpu_stats *stats = this_cpu_ptr(pp->stats);