From patchwork Wed Nov 29 11:23:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Liang Chen X-Patchwork-Id: 13472671 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C2917C4167B for ; Wed, 29 Nov 2023 11:24:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5959A6B03C9; Wed, 29 Nov 2023 06:24:55 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 542F66B03CA; Wed, 29 Nov 2023 06:24:55 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3E3BD6B03CB; Wed, 29 Nov 2023 06:24:55 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 2A6AC6B03C9 for ; Wed, 29 Nov 2023 06:24:55 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id F3DF2C049C for ; Wed, 29 Nov 2023 11:24:54 +0000 (UTC) X-FDA: 81510759750.19.1F57008 Received: from mail-pl1-f171.google.com (mail-pl1-f171.google.com [209.85.214.171]) by imf10.hostedemail.com (Postfix) with ESMTP id 31A06C001F for ; Wed, 29 Nov 2023 11:24:52 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=NC+hHV9g; spf=pass (imf10.hostedemail.com: domain of liangchen.linux@gmail.com designates 209.85.214.171 as permitted sender) smtp.mailfrom=liangchen.linux@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1701257093; a=rsa-sha256; cv=none; b=pVSzpmLRc5e0ZkcR0ZrZ+CnIiX4bHH2YHsUNoSwCe7nrt8lNCl3kLPiCKqZnaYm5GuKTUB tHspJi6JKULuotO3dGkfD7Y5xLr91tjuvOLdokKJFr2rwWbhq1GwOxOcfHsDLhpyNbEJ2h /6JIf77/fQWEgzDjvuUtqL8H/B9IiLg= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=NC+hHV9g; spf=pass (imf10.hostedemail.com: domain of liangchen.linux@gmail.com designates 209.85.214.171 as permitted sender) smtp.mailfrom=liangchen.linux@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1701257093; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=60yowogr+zuknO3ERs4O7G8fQYZaBv4s1gl54jybDiQ=; b=3SdfXN7pQHtU73i24nVsex0lJ2Gx4Iia/Pr8+irZXCX9e7jGMCUxJ0vHpjqW1u7wwI8C9j 8kxYR7idL9Szmq/2xgwZPlx3xdohPfB1r8QUxX5x5pfSAjJ1o515vh3wnKWkVQoISNe1SS hDXK5GNwoB2cFSsofLSmmyr6P6sHrA8= Received: by mail-pl1-f171.google.com with SMTP id d9443c01a7336-1d00689f5c8so12293355ad.3 for ; Wed, 29 Nov 2023 03:24:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1701257092; x=1701861892; darn=kvack.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=60yowogr+zuknO3ERs4O7G8fQYZaBv4s1gl54jybDiQ=; b=NC+hHV9gmpCCuNDyxJyW7gSHcnrdn6rlXg9tfaQHt6DpR6lXysOJ0cM5sB+j1oQFnV 9/6etbUqaZH2h1XJm6q+zQ23zemTYVHjDyu1Y4V611Pvfvi53bfKyVvt6UwLnY2lewUc JJzaoCGZjC9F/OfhJfo01sKszKCRCVF/UTC44jLGpHYeG0woxM7TV0p0v+z3sTg9pKr/ TiYEHHUp0tyIMk5zk60xWBvLHZkB7JjaOGSlsP1ZdSkxL/PiBYEVoRe/e8d1Lswvqohk KBAe2IW72RU8xEy2vp0T1LdrqUvXFjhezxmFLZOvzWWRf2CHJ22zRt9eWhlPAugZKr21 OqLQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701257092; x=1701861892; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=60yowogr+zuknO3ERs4O7G8fQYZaBv4s1gl54jybDiQ=; b=ihNSkM1fS16+g9WLIVPmKkp4bvxNaXoHc6MwqZcDX9Y6WqXwOY/Ci16FUyfCAyo1lv 6KHSEosE4aXOYhDMukFPPPCMepshYjkke88E5b2dSzrfoVydtSPhLLZWySYE3i+jbc/7 Wo+8PesxuoZN+cZszlw3S8cdNQdO+8e3yOZ/UvJVf4Oy0G2RDwDLD2QPl5TGQIZ/DmEH pkHJC9pu4V5y1WF/0TKEJ04dU36gOiIcOaAd4sRR/qTgx/rmF4sAYFsuTQMNnlBDCoPk 4rLgN2YESTbYk1NaZABYCJc5I1nYUxY5hzUR9uNdaQmbh2XXPeXOHP7XOGe86q2kHriV cZWA== X-Gm-Message-State: AOJu0YxLDPRga+oQXQt80enmae0u7VBWn9L5sv1XLsFsRMCMo13y1lWz c+pZhptdKLBhvlIi2uQ0DhQ= X-Google-Smtp-Source: AGHT+IG3ycrW11c+jOMiRX0m4x0f2LMO5kHkyzpQoQeO4N3U4j5Xb+awhZJOOwUSY1nrq3eoWqcStQ== X-Received: by 2002:a17:903:32c8:b0:1cf:b12a:a9eb with SMTP id i8-20020a17090332c800b001cfb12aa9ebmr19342480plr.19.1701257092063; Wed, 29 Nov 2023 03:24:52 -0800 (PST) Received: from localhost.localdomain ([89.187.161.180]) by smtp.gmail.com with ESMTPSA id c6-20020a170902c1c600b001cfd0ed1604sm5460710plc.87.2023.11.29.03.24.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Nov 2023 03:24:50 -0800 (PST) From: Liang Chen To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, hawk@kernel.org, ilias.apalodimas@linaro.org, linyunsheng@huawei.com Cc: netdev@vger.kernel.org, linux-mm@kvack.org, liangchen.linux@gmail.com Subject: [PATCH net-next v5 4/4] skbuff: Optimization of SKB coalescing for page pool Date: Wed, 29 Nov 2023 19:23:04 +0800 Message-Id: <20231129112304.67836-5-liangchen.linux@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20231129112304.67836-1-liangchen.linux@gmail.com> References: <20231129112304.67836-1-liangchen.linux@gmail.com> MIME-Version: 1.0 X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 31A06C001F X-Stat-Signature: owk33fk4mr7zdoo45fh9g63qayimaufb X-Rspam-User: X-HE-Tag: 1701257092-828694 X-HE-Meta: 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 XOxviuk2 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: In order to address the issues encountered with commit 1effe8ca4e34 ("skbuff: fix coalescing for page_pool fragment recycling"), the combination of the following condition was excluded from skb coalescing: from->pp_recycle = 1 from->cloned = 1 to->pp_recycle = 1 However, with page pool environments, the aforementioned combination can be quite common(ex. NetworkMananger may lead to the additional packet_type being registered, thus the cloning). In scenarios with a higher number of small packets, it can significantly affect the success rate of coalescing. For example, considering packets of 256 bytes size, our comparison of coalescing success rate is as follows: Without page pool: 70% With page pool: 13% Consequently, this has an impact on performance: Without page pool: 2.57 Gbits/sec With page pool: 2.26 Gbits/sec Therefore, it seems worthwhile to optimize this scenario and enable coalescing of this particular combination. To achieve this, we need to ensure the correct increment of the "from" SKB page's page pool reference count (pp_ref_count). Following this optimization, the success rate of coalescing measured in our environment has improved as follows: With page pool: 60% This success rate is approaching the rate achieved without using page pool, and the performance has also been improved: With page pool: 2.52 Gbits/sec Below is the performance comparison for small packets before and after this optimization. We observe no impact to packets larger than 4K. packet size before after improved (bytes) (Gbits/sec) (Gbits/sec) 128 1.19 1.27 7.13% 256 2.26 2.52 11.75% 512 4.13 4.81 16.50% 1024 6.17 6.73 9.05% 2048 14.54 15.47 6.45% 4096 25.44 27.87 9.52% Signed-off-by: Liang Chen Reviewed-by: Yunsheng Lin --- include/net/page_pool/helpers.h | 5 ++++ net/core/skbuff.c | 41 +++++++++++++++++++++++---------- 2 files changed, 34 insertions(+), 12 deletions(-) diff --git a/include/net/page_pool/helpers.h b/include/net/page_pool/helpers.h index 9dc8eaf8a959..268bc9d9ffd3 100644 --- a/include/net/page_pool/helpers.h +++ b/include/net/page_pool/helpers.h @@ -278,6 +278,11 @@ static inline long page_pool_unref_page(struct page *page, long nr) return ret; } +static inline void page_pool_ref_page(struct page *page) +{ + atomic_long_inc(&page->pp_ref_count); +} + static inline bool page_pool_is_last_ref(struct page *page) { /* If page_pool_unref_page() returns 0, we were the last user */ diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 31e57c29c556..2d797f33d809 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -947,6 +947,24 @@ static bool skb_pp_recycle(struct sk_buff *skb, void *data, bool napi_safe) return napi_pp_put_page(virt_to_page(data), napi_safe); } +/** + * skb_pp_frag_ref() - Increase fragment reference count of a page + * @page: page of the fragment on which to increase a reference + * + * Increase fragment reference count (pp_ref_count) on a page, but if it is + * not a page pool page, fallback to increase a reference(_refcount) on a + * normal page. + */ +static void skb_pp_frag_ref(struct page *page) +{ + struct page *head_page = compound_head(page); + + if (likely(skb_frag_is_pp_page(head_page))) + page_pool_ref_page(head_page); + else + page_ref_inc(head_page); +} + static void skb_kfree_head(void *head, unsigned int end_offset) { if (end_offset == SKB_SMALL_HEAD_HEADROOM) @@ -5769,17 +5787,12 @@ bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from, return false; /* In general, avoid mixing page_pool and non-page_pool allocated - * pages within the same SKB. Additionally avoid dealing with clones - * with page_pool pages, in case the SKB is using page_pool fragment - * references (page_pool_alloc_frag()). Since we only take full page - * references for cloned SKBs at the moment that would result in - * inconsistent reference counts. - * In theory we could take full references if @from is cloned and - * !@to->pp_recycle but its tricky (due to potential race with - * the clone disappearing) and rare, so not worth dealing with. + * pages within the same SKB. In theory we could take full + * references if @from is cloned and !@to->pp_recycle but its + * tricky (due to potential race with the clone disappearing) and + * rare, so not worth dealing with. */ - if (to->pp_recycle != from->pp_recycle || - (from->pp_recycle && skb_cloned(from))) + if (to->pp_recycle != from->pp_recycle) return false; if (len <= skb_tailroom(to)) { @@ -5836,8 +5849,12 @@ bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from, /* if the skb is not cloned this does nothing * since we set nr_frags to 0. */ - for (i = 0; i < from_shinfo->nr_frags; i++) - __skb_frag_ref(&from_shinfo->frags[i]); + if (from->pp_recycle) + for (i = 0; i < from_shinfo->nr_frags; i++) + skb_pp_frag_ref(skb_frag_page(&from_shinfo->frags[i])); + else + for (i = 0; i < from_shinfo->nr_frags; i++) + __skb_frag_ref(&from_shinfo->frags[i]); to->truesize += delta; to->len += len;