From nobody Tue Apr 16 23:19:49 2024 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68302C77B7A for ; Fri, 26 May 2023 09:28:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243113AbjEZJ2h (ORCPT ); Fri, 26 May 2023 05:28:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38688 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243095AbjEZJ22 (ORCPT ); Fri, 26 May 2023 05:28:28 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2780F95; Fri, 26 May 2023 02:28:22 -0700 (PDT) Received: from dggpemm500005.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4QSKKt0CHTzsSPV; Fri, 26 May 2023 17:26:10 +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; Fri, 26 May 2023 17:28:19 +0800 From: Yunsheng Lin To: , , CC: , , Yunsheng Lin , Lorenzo Bianconi , Alexander Duyck , Jesper Dangaard Brouer , Ilias Apalodimas , Eric Dumazet Subject: [PATCH net-next 1/2] page_pool: unify frag page and non-frag page handling Date: Fri, 26 May 2023 17:26:14 +0800 Message-ID: <20230526092616.40355-2-linyunsheng@huawei.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20230526092616.40355-1-linyunsheng@huawei.com> References: <20230526092616.40355-1-linyunsheng@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.69.192.56] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemm500005.china.huawei.com (7.185.36.74) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Currently page_pool_dev_alloc_pages() can not be called when PP_FLAG_PAGE_FRAG is set, because it does not use the frag reference counting. As we are already doing a optimization by not updating page->pp_frag_count in page_pool_defrag_page() for the last frag user, and non-frag page only have one user, so we utilize that to unify frag page and non-frag page handling, so that page_pool_dev_alloc_pages() can also be called with PP_FLAG_PAGE_FRAG set. Signed-off-by: Yunsheng Lin CC: Lorenzo Bianconi CC: Alexander Duyck --- include/net/page_pool.h | 38 +++++++++++++++++++++++++++++++------- net/core/page_pool.c | 1 + 2 files changed, 32 insertions(+), 7 deletions(-) diff --git a/include/net/page_pool.h b/include/net/page_pool.h index c8ec2f34722b..ea7a0c0592a5 100644 --- a/include/net/page_pool.h +++ b/include/net/page_pool.h @@ -50,6 +50,9 @@ PP_FLAG_DMA_SYNC_DEV |\ PP_FLAG_PAGE_FRAG) =20 +#define PAGE_POOL_DMA_USE_PP_FRAG_COUNT \ + (sizeof(dma_addr_t) > sizeof(unsigned long)) + /* * Fast allocation side cache array/stack * @@ -295,13 +298,20 @@ void page_pool_put_defragged_page(struct page_pool *p= ool, struct page *page, */ static inline void page_pool_fragment_page(struct page *page, long nr) { - atomic_long_set(&page->pp_frag_count, nr); + if (!PAGE_POOL_DMA_USE_PP_FRAG_COUNT) + atomic_long_set(&page->pp_frag_count, nr); } =20 +/* We need to reset frag_count back to 1 for the last user to allow + * only one user in case the page is recycled and allocated as non-frag + * page. + */ static inline long page_pool_defrag_page(struct page *page, long nr) { long ret; =20 + BUILD_BUG_ON(__builtin_constant_p(nr) && nr !=3D 1); + /* If nr =3D=3D pp_frag_count then we have cleared all remaining * references to the page. No need to actually overwrite it, instead * we can leave this to be overwritten by the calling function. @@ -311,19 +321,36 @@ static inline long page_pool_defrag_page(struct page = *page, long nr) * especially when dealing with a page that may be partitioned * into only 2 or 3 pieces. */ - if (atomic_long_read(&page->pp_frag_count) =3D=3D nr) + if (atomic_long_read(&page->pp_frag_count) =3D=3D nr) { + /* As we have ensured nr is always one for constant case + * using the BUILD_BUG_ON() as above, only need to handle + * the non-constant case here for frag count draining. + */ + if (!__builtin_constant_p(nr)) + atomic_long_set(&page->pp_frag_count, 1); + return 0; + } =20 ret =3D atomic_long_sub_return(nr, &page->pp_frag_count); WARN_ON(ret < 0); + + /* Reset frag count back to 1, this should be the rare case when + * two users call page_pool_defrag_page() currently. + */ + if (!ret) + atomic_long_set(&page->pp_frag_count, 1); + return ret; } =20 static inline bool page_pool_is_last_frag(struct page_pool *pool, struct page *page) { - /* If fragments aren't enabled or count is 0 we were the last user */ - return !(pool->p.flags & PP_FLAG_PAGE_FRAG) || + /* When dma_addr_upper is overlapped with pp_frag_count + * or we were the last page frag user. + */ + return PAGE_POOL_DMA_USE_PP_FRAG_COUNT || (page_pool_defrag_page(page, 1) =3D=3D 0); } =20 @@ -357,9 +384,6 @@ static inline void page_pool_recycle_direct(struct page= _pool *pool, page_pool_put_full_page(pool, page, true); } =20 -#define PAGE_POOL_DMA_USE_PP_FRAG_COUNT \ - (sizeof(dma_addr_t) > sizeof(unsigned long)) - static inline dma_addr_t page_pool_get_dma_addr(struct page *page) { dma_addr_t ret =3D page->dma_addr; diff --git a/net/core/page_pool.c b/net/core/page_pool.c index e212e9d7edcb..0868aa8f6323 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -334,6 +334,7 @@ static void page_pool_set_pp_info(struct page_pool *poo= l, { page->pp =3D pool; page->pp_magic |=3D PP_SIGNATURE; + page_pool_fragment_page(page, 1); if (pool->p.init_callback) pool->p.init_callback(page, pool->p.init_arg); } --=20 2.33.0 From nobody Tue Apr 16 23:19:49 2024 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BAE77C77B7C for ; Fri, 26 May 2023 09:28:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242722AbjEZJ2k (ORCPT ); Fri, 26 May 2023 05:28:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242732AbjEZJ23 (ORCPT ); Fri, 26 May 2023 05:28:29 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 96524195; Fri, 26 May 2023 02:28:23 -0700 (PDT) Received: from dggpemm500005.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4QSKNL70jZzTjvF; Fri, 26 May 2023 17:28:18 +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; Fri, 26 May 2023 17:28:21 +0800 From: Yunsheng Lin To: , , CC: , , Yunsheng Lin , Lorenzo Bianconi , Alexander Duyck , Jesper Dangaard Brouer , Ilias Apalodimas , Eric Dumazet Subject: [PATCH net-next 2/2] page_pool: support non-frag page for page_pool_alloc_frag() Date: Fri, 26 May 2023 17:26:15 +0800 Message-ID: <20230526092616.40355-3-linyunsheng@huawei.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20230526092616.40355-1-linyunsheng@huawei.com> References: <20230526092616.40355-1-linyunsheng@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.69.192.56] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemm500005.china.huawei.com (7.185.36.74) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" There is performance penalty with using page frag support when user requests a larger frag size and a page only supports one frag user, see [1]. It seems like user may request different frag size depending on the mtu and packet size, provide an option to allocate non-frag page when a whole page is not able to hold two frags, so that user has a unified interface for the memory allocation with least memory utilization and performance penalty. 1. https://lore.kernel.org/netdev/ZEU+vospFdm08IeE@localhost.localdomain/ Signed-off-by: Yunsheng Lin CC: Lorenzo Bianconi CC: Alexander Duyck --- net/core/page_pool.c | 47 +++++++++++++++++++++++++++----------------- 1 file changed, 29 insertions(+), 18 deletions(-) diff --git a/net/core/page_pool.c b/net/core/page_pool.c index 0868aa8f6323..e84ec6eabefd 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -699,14 +699,27 @@ struct page *page_pool_alloc_frag(struct page_pool *p= ool, unsigned int max_size =3D PAGE_SIZE << pool->p.order; struct page *page =3D pool->frag_page; =20 - if (WARN_ON(!(pool->p.flags & PP_FLAG_PAGE_FRAG) || - size > max_size)) + if (unlikely(size > max_size)) return NULL; =20 + if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT) { + *offset =3D 0; + return page_pool_alloc_pages(pool, gfp); + } + size =3D ALIGN(size, dma_get_cache_alignment()); - *offset =3D pool->frag_offset; =20 - if (page && *offset + size > max_size) { + if (page) { + *offset =3D pool->frag_offset; + + if (*offset + size <=3D max_size) { + pool->frag_users++; + pool->frag_offset =3D *offset + size; + alloc_stat_inc(pool, fast); + return page; + } + + pool->frag_page =3D NULL; page =3D page_pool_drain_frag(pool, page); if (page) { alloc_stat_inc(pool, fast); @@ -714,26 +727,24 @@ struct page *page_pool_alloc_frag(struct page_pool *p= ool, } } =20 - if (!page) { - page =3D page_pool_alloc_pages(pool, gfp); - if (unlikely(!page)) { - pool->frag_page =3D NULL; - return NULL; - } - - pool->frag_page =3D page; + page =3D page_pool_alloc_pages(pool, gfp); + if (unlikely(!page)) + return NULL; =20 frag_reset: - pool->frag_users =3D 1; + /* return page as non-frag page if a page is not able to + * hold two frags for the current requested size. + */ + if (unlikely(size << 1 > max_size)) { *offset =3D 0; - pool->frag_offset =3D size; - page_pool_fragment_page(page, BIAS_MAX); return page; } =20 - pool->frag_users++; - pool->frag_offset =3D *offset + size; - alloc_stat_inc(pool, fast); + pool->frag_page =3D page; + pool->frag_users =3D 1; + *offset =3D 0; + pool->frag_offset =3D size; + page_pool_fragment_page(page, BIAS_MAX); return page; } EXPORT_SYMBOL(page_pool_alloc_frag); --=20 2.33.0