From patchwork Mon Jun 12 13:02:54 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yunsheng Lin X-Patchwork-Id: 13276505 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 154ED19BDE for ; Mon, 12 Jun 2023 13:05:22 +0000 (UTC) Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C82BE69; Mon, 12 Jun 2023 06:05:20 -0700 (PDT) Received: from dggpemm500005.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4QfsKK2JtlzLqhM; Mon, 12 Jun 2023 21:02:13 +0800 (CST) 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 15.1.2507.23; Mon, 12 Jun 2023 21:05:17 +0800 From: Yunsheng Lin To: , , CC: , , Yunsheng Lin , Lorenzo Bianconi , Alexander Duyck , Jesper Dangaard Brouer , Ilias Apalodimas , Eric Dumazet Subject: [PATCH net-next v4 3/5] page_pool: introduce page_pool_alloc() API Date: Mon, 12 Jun 2023 21:02:54 +0800 Message-ID: <20230612130256.4572-4-linyunsheng@huawei.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20230612130256.4572-1-linyunsheng@huawei.com> References: <20230612130256.4572-1-linyunsheng@huawei.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Originating-IP: [10.69.192.56] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemm500005.china.huawei.com (7.185.36.74) X-CFilter-Loop: Reflected X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org Currently page pool supports the below use cases: use case 1: allocate page without page splitting using page_pool_alloc_pages() API if the driver knows that the memory it need is always bigger than half of the page allocated from page pool. use case 2: allocate page frag with page splitting using page_pool_alloc_frag() API if the driver knows that the memory it need is always smaller than or equal to the half of the page allocated from page pool. There is emerging use case [1] & [2] that is a mix of the above two case: the driver doesn't know the size of memory it need beforehand, so the driver may use something like below to allocate memory with least memory utilization and performance penalty: if (size << 1 > max_size) page = page_pool_alloc_pages(); else page = page_pool_alloc_frag(); To avoid the driver doing something like above, add the page_pool_alloc() API to support the above use case, and update the true size of memory that is acctually allocated by updating '*size' back to the driver in order to avoid the truesize underestimate problem. 1. https://lore.kernel.org/all/d3ae6bd3537fbce379382ac6a42f67e22f27ece2.1683896626.git.lorenzo@kernel.org/ 2. https://lore.kernel.org/all/20230526054621.18371-3-liangchen.linux@gmail.com/ Signed-off-by: Yunsheng Lin CC: Lorenzo Bianconi CC: Alexander Duyck --- include/net/page_pool.h | 43 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/include/net/page_pool.h b/include/net/page_pool.h index 0b8cd2acc1d7..c135cd157cea 100644 --- a/include/net/page_pool.h +++ b/include/net/page_pool.h @@ -260,6 +260,49 @@ static inline struct page *page_pool_dev_alloc_frag(struct page_pool *pool, return page_pool_alloc_frag(pool, offset, size, gfp); } +static inline struct page *page_pool_alloc(struct page_pool *pool, + unsigned int *offset, + unsigned int *size, gfp_t gfp) +{ + unsigned int max_size = PAGE_SIZE << pool->p.order; + struct page *page; + + *size = ALIGN(*size, dma_get_cache_alignment()); + + if (WARN_ON(*size > max_size)) + return NULL; + + if ((*size << 1) > max_size || PAGE_POOL_DMA_USE_PP_FRAG_COUNT) { + *size = max_size; + *offset = 0; + return page_pool_alloc_pages(pool, gfp); + } + + page = __page_pool_alloc_frag(pool, offset, *size, gfp); + if (unlikely(!page)) + return NULL; + + /* There is very likely not enough space for another frag, so append the + * remaining size to the current frag to avoid truesize underestimate + * problem. + */ + if (pool->frag_offset + *size > max_size) { + *size = max_size - *offset; + pool->frag_offset = max_size; + } + + return page; +} + +static inline struct page *page_pool_dev_alloc(struct page_pool *pool, + unsigned int *offset, + unsigned int *size) +{ + gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN); + + return page_pool_alloc(pool, offset, size, 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 */