From patchwork Sat Jul 10 07:43:21 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yunsheng Lin X-Patchwork-Id: 12368385 X-Patchwork-Delegate: kuba@kernel.org 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=-17.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 1547AC07E95 for ; Sat, 10 Jul 2021 07:44:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC63C613EC for ; Sat, 10 Jul 2021 07:44:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232421AbhGJHrC (ORCPT ); Sat, 10 Jul 2021 03:47:02 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:6906 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232123AbhGJHqx (ORCPT ); Sat, 10 Jul 2021 03:46:53 -0400 Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4GMMQ80Q3Lz79mm; Sat, 10 Jul 2021 15:40:32 +0800 (CST) Received: from dggpemm500005.china.huawei.com (7.185.36.74) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Sat, 10 Jul 2021 15:44:01 +0800 Received: from localhost.localdomain (10.69.192.56) by dggpemm500005.china.huawei.com (7.185.36.74) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Sat, 10 Jul 2021 15:44:00 +0800 From: Yunsheng Lin To: , CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: [PATCH rfc v2 4/5] page_pool: support page frag API for page pool Date: Sat, 10 Jul 2021 15:43:21 +0800 Message-ID: <1625903002-31619-5-git-send-email-linyunsheng@huawei.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1625903002-31619-1-git-send-email-linyunsheng@huawei.com> References: <1625903002-31619-1-git-send-email-linyunsheng@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.69.192.56] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500005.china.huawei.com (7.185.36.74) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC Currently each desc use a whole page to do ping-pong page reusing in most driver. As the page pool has support page recycling based on elevated refcnt, it makes sense to add a page frag API in page pool to split a page to different frag to serve multi descriptions. This means a huge memory saving for kernel with page size of 64K, as a page can be used by 32 descriptions with 2k buffer size, comparing to each desc using one page currently. Signed-off-by: Yunsheng Lin --- include/net/page_pool.h | 14 ++++++++++++++ net/core/page_pool.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 63 insertions(+) diff --git a/include/net/page_pool.h b/include/net/page_pool.h index f0e708d..06a5e43 100644 --- a/include/net/page_pool.h +++ b/include/net/page_pool.h @@ -80,6 +80,7 @@ struct page_pool_params { enum dma_data_direction dma_dir; /* DMA mapping direction */ unsigned int max_len; /* max DMA sync memory size */ unsigned int offset; /* DMA addr offset */ + unsigned int frag_size; }; struct page_pool { @@ -91,6 +92,8 @@ struct page_pool { unsigned long defer_warn; u32 pages_state_hold_cnt; + unsigned int frag_offset; + struct page *frag_page; /* * Data structure for allocation side @@ -140,6 +143,17 @@ static inline struct page *page_pool_dev_alloc_pages(struct page_pool *pool) return page_pool_alloc_pages(pool, gfp); } +struct page *page_pool_alloc_frag(struct page_pool *pool, + unsigned int *offset, gfp_t gfp); + +static inline struct page *page_pool_dev_alloc_frag(struct page_pool *pool, + unsigned int *offset) +{ + gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN); + + return page_pool_alloc_frag(pool, offset, gfp); +} + /* get the stored dma direction. A driver might decide to treat this locally and * avoid the extra cache line from page_pool to determine the direction */ diff --git a/net/core/page_pool.c b/net/core/page_pool.c index a87cbe1..b787033 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -350,6 +350,53 @@ struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp) } EXPORT_SYMBOL(page_pool_alloc_pages); +struct page *page_pool_alloc_frag(struct page_pool *pool, + unsigned int *offset, gfp_t gfp) +{ + unsigned int frag_offset = pool->frag_offset; + unsigned int frag_size = pool->p.frag_size; + struct page *frag_page = pool->frag_page; + unsigned int max_len = pool->p.max_len; + + if (!frag_page || frag_offset + frag_size > max_len) { + frag_page = page_pool_alloc_pages(pool, gfp); + if (unlikely(!frag_page)) { + pool->frag_page = NULL; + return NULL; + } + + pool->frag_page = frag_page; + frag_offset = 0; + + page_pool_sub_bias(pool, frag_page, + max_len / frag_size - 1); + } + + *offset = frag_offset; + pool->frag_offset = frag_offset + frag_size; + + return frag_page; +} +EXPORT_SYMBOL(page_pool_alloc_frag); + +static void page_pool_empty_frag(struct page_pool *pool) +{ + unsigned int frag_offset = pool->frag_offset; + unsigned int frag_size = pool->p.frag_size; + struct page *frag_page = pool->frag_page; + unsigned int max_len = pool->p.max_len; + + if (!frag_page) + return; + + while (frag_offset + frag_size <= max_len) { + page_pool_put_full_page(pool, frag_page, false); + frag_offset += frag_size; + } + + pool->frag_page = NULL; +} + /* Calculate distance between two u32 values, valid if distance is below 2^(31) * https://en.wikipedia.org/wiki/Serial_number_arithmetic#General_Solution */ @@ -670,6 +717,8 @@ void page_pool_destroy(struct page_pool *pool) if (!page_pool_put(pool)) return; + page_pool_empty_frag(pool); + if (!page_pool_release(pool)) return;