From nobody Sun Oct 5 21:59:54 2025 Received: from invmail4.hynix.com (exvmail4.hynix.com [166.125.252.92]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 730A42882C3; Tue, 29 Jul 2025 11:02:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=166.125.252.92 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753786977; cv=none; b=d88k0BDhq+hxo4AGnQ7/ho8S+n3yqXP5nt2sWfLV7XNdQSo0D3EZjgVuh0LVJPXoG7jMZvEh7odhAS7JhZm+lffcgikXJf6aPfpVOS26bsO2BVtWE3rYfFVHZaJpxLPbaYeTSlJCMgNoZNYYICeFzLoOExIux+mO8axsHyYjatc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753786977; c=relaxed/simple; bh=SGDXxb6mZmT3ILuEcG0G3dGQ59DGmBBLAISNgGDrlJs=; h=From:To:Cc:Subject:Date:Message-Id; b=N3l59koOxWuLUJRneQ278zjhwOhtfibfJbGh51oiqnq28mVZGgJHpbBtDzGHuGyKwwLEx0/la1vjmuSM6C5idj4iD7zXb3dxVDa6I/nVqMzZMgBfdyqvgtNJ8iwRV3ZVlKoK/eb+jayvxo3/saAqGpob8Prx05B5YUMNB0j2VME= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com; spf=pass smtp.mailfrom=sk.com; arc=none smtp.client-ip=166.125.252.92 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sk.com X-AuditID: a67dfc5b-681ff7000002311f-53-6888aa58c3dd From: Byungchul Park To: linux-mm@kvack.org, netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel_team@skhynix.com, harry.yoo@oracle.com, ast@kernel.org, daniel@iogearbox.net, davem@davemloft.net, kuba@kernel.org, hawk@kernel.org, john.fastabend@gmail.com, sdf@fomichev.me, saeedm@nvidia.com, leon@kernel.org, tariqt@nvidia.com, mbloch@nvidia.com, andrew+netdev@lunn.ch, edumazet@google.com, pabeni@redhat.com, akpm@linux-foundation.org, david@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, horms@kernel.org, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, ilias.apalodimas@linaro.org, willy@infradead.org, brauner@kernel.org, kas@kernel.org, yuzhao@google.com, usamaarif642@gmail.com, baolin.wang@linux.alibaba.com, almasrymina@google.com, toke@redhat.com, asml.silence@gmail.com, bpf@vger.kernel.org, linux-rdma@vger.kernel.org, sfr@canb.auug.org.au Subject: [PATCH linux-next v3] mm, page_pool: introduce a new page type for page pool in page type Date: Tue, 29 Jul 2025 20:02:10 +0900 Message-Id: <20250729110210.48313-1-byungchul@sk.com> X-Mailer: git-send-email 2.17.1 X-Brightmail-Tracker: H4sIAAAAAAAAAzXRe0hTcRQH8H67d/del4PLkrwZGAwiMVIrpRNG2B/CjYiEMKT+0Jm3ttIp U6crhC2lqalJafiYtRRNp2Jt+cSJ75kmmWlMm89Qwle+Wr7CfOB/H873nO8/h8JENtyFkslj OIVcEi4mBLhg3rHwTJAhWeo1U+QDuqoKAsrX4uHdeB0fdIYaBKvrP0jYNnciWGm3EDDbtoyg 6K0dA92XJBz+VG1gMNU5SUK58TqMlUzj0KitxWDyeRcB6UmbGJjXF0h4UlfKA51JTUJfTQYf sjaKMahVj5PwrUFHwGjFNh+mW9Nx+JRXhsNidjsGYxl+0Kk/CvaeOQTtVbU8sKcVEDCY28CD avMgCS/79QT8TBpD0N82iUP2VjIB+ZoMBJtrO5ULmat8yO8YJf1OsxqrlWDb5n5j7MeyIR5r bermsfV5IySrN8ayplJ3NtXaj7FGQwrBGpdfkKzteyPBduVs4mz9xEW2vm6Fx6YnLhDs0tQw HuB0W3ApjAuXKTmF5+UQgXRT4xBlCYzvMZqQGs34pyIHiqG9mUVzC37g5C0tuWuCPsVYrevY rp1oL6Y0e3XHAgqjP5PMq+bEvaUjdCgz3TaNdo3TJ5neavXOnKKEtA9jG4nb7zzBlL9v3rtl 6AKKsaX8w/aDY0xLqRXPRIf16JABiWRyZYREFu7tIVXJZfEedyMjjGjn5yUJW3fq0HLfzVZE U0jsKJSmaKUivkQZrYpoRQyFiZ2EUcVPpSJhmET1iFNEBitiw7noVnScwsXOwnP2uDARfV8S wz3kuChOcZDyKAcXNVLOV7r1TJiuBv0NlLu+fnzhzazllzaEpx2Qnb/X7qM0Dy8JclUi2ZjI 9GDRdmsubdXPyd5hG7Ljnb5xbleE/YPBgii+c8KzpkClkBrOsjT6FvcEBX2YvzHs7Bm6kl6Y UGR0Hij0yhypcPyaUxmiu5bgr+xu1mmUJfzeAFe+hxiPlkrOumOKaMl/uVc42+8CAAA= X-Brightmail-Tracker: H4sIAAAAAAAAAzWRa0hTcRyG/e+cnXMcDg627HShy0oSKzPQ+nXBhG7/gi6Q0cUPOevURnPa lssFxbylVtq6rLIWGKLpFi2m6SZOzJmXLCvDWjenhoNKltmynFJp0beH9315vrwMEdpAzmAU qmO8WiVTSikRKdq2OnvJHnO+PLq8bzqYrHcosPzMgNu9diGYzDUI/KNvafjtbEHwrbmVgs+u YQSlt0YIMD3NIeG7NUDAQEs/DRbbVvCUe0moz6sloP98GwWFOWMEOEd9NGTZKwRgqtLT4LrZ LoRnNUVCuBwoI6BW30vDizoTBT13fgvB21RIQvv1ShKGjM0EeIrioaUkDEY6BhE0W2sFMHLu JgXdxXUCuO/spuFSVwkFH3I8CLpc/SQYx/MpuJFZhGDs54TSZ/AL4cbDHjp+Mc50uynsGvxC 4OrK1wLsbngkwI7r72lcYkvHVRWR+Iy7i8A2cwGFbcMXafzuZT2F266NkdjRtxI77N8EuDDb R+GvA2/IHVP3idYc5JUKLa9eGpckko9lBqe17srosFUhPfq04QwKZjg2hssfz6MnmWIXcm73 KDHJEjaaqzD6J1jEEOxjmrvSmP13NIVN5rwuL5pkkg3nntzXT+QMI2ZjuXfvj/9zzuEs9xoJ A2JKUJAZSRQqbYpMoYyN0hyR61SKjKgDqSk2NPFq+cnxC3bkf7GpCbEMkoaI5QV58lChTKvR pTQhjiGkEnFa2Wl5qPigTHeCV6fuV6creU0TmsmQ0mniLbv5pFD2sOwYf4Tn03j1/1bABM/Q o/1Gnb0462Pqj4w4c1XpSevenYVJyy/NT269m7gx6GtMIMhPxCcaKh90rk1ICuz1DA3wc5+f DZ4HUduw8BR/Yd3VmgV9kTna9c5VljiPL/esqqCzOnd3z2igU3IUvwopfRKRsEcQ0bHZER73 cHY7u2JRs4EN+3X00PaBWdLeLeZOKamRy5ZFEmqN7A+KYYIM0QIAAA== X-CFilter-Loop: Reflected Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Changes from v2: 1. Rebase on linux-next as of Jul 29. 2. Skip 'niov->pp =3D NULL' when it's allocated using __GFP_ZERO. 3. Change trivial coding style. (feedbacked by Mina) 4. Add Co-developed-by, Acked-by, and Reviewed-by properly. Thanks to all. Changes from v1: 1. Rebase on linux-next. 2. Initialize net_iov->pp =3D NULL when allocating net_iov in net_devmem_bind_dmabuf() and io_zcrx_create_area(). 3. Use ->pp for net_iov to identify if it's pp rather than always consider net_iov as pp. 4. Add Suggested-by: David Hildenbrand . Acked-by: David Hildenbrand Acked-by: Zi Yan Reviewed-by: Mina Almasry Suggested-by: David Hildenbrand ---8<--- From 88bcb9907a0cef65a9c0adf35e144f9eb67e0542 Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Tue, 29 Jul 2025 19:49:44 +0900 Subject: [PATCH linux-next v3] mm, page_pool: introduce a new page type for= page pool in page type ->pp_magic field in struct page is current used to identify if a page belongs to a page pool. However, ->pp_magic will be removed and page type bit in struct page e.i. PGTY_netpp can be used for that purpose. Introduce and use the page type APIs e.g. PageNetpp(), __SetPageNetpp(), and __ClearPageNetpp() instead, and remove the existing APIs accessing ->pp_magic e.g. page_pool_page_is_pp(), netmem_or_pp_magic(), and netmem_clear_pp_magic(). For net_iov, use ->pp to identify if it's pp, with making sure that ->pp is NULL for non-pp net_iov. This work was inspired by the following link: [1] https://lore.kernel.org/all/582f41c0-2742-4400-9c81-0d46bf4e8314@gmail.= com/ While at it, move the sanity check for page pool to on free. Suggested-by: David Hildenbrand Co-developed-by: Pavel Begunkov Signed-off-by: Pavel Begunkov Signed-off-by: Byungchul Park Acked-by: David Hildenbrand Reviewed-by: Mina Almasry --- .../net/ethernet/mellanox/mlx5/core/en/xdp.c | 2 +- include/linux/mm.h | 27 +++---------------- include/linux/page-flags.h | 6 +++++ include/net/netmem.h | 2 +- io_uring/zcrx.c | 4 +++ mm/page_alloc.c | 7 +++-- net/core/devmem.c | 1 + net/core/netmem_priv.h | 23 +++++++--------- net/core/page_pool.c | 10 +++++-- 9 files changed, 37 insertions(+), 45 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c b/drivers/net= /ethernet/mellanox/mlx5/core/en/xdp.c index 5d51600935a6..def274f5c1ca 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c @@ -707,7 +707,7 @@ static void mlx5e_free_xdpsq_desc(struct mlx5e_xdpsq *s= q, xdpi =3D mlx5e_xdpi_fifo_pop(xdpi_fifo); page =3D xdpi.page.page; =20 - /* No need to check page_pool_page_is_pp() as we + /* No need to check PageNetpp() as we * know this is a page_pool page. */ page_pool_recycle_direct(pp_page_to_nmdesc(page)->pp, diff --git a/include/linux/mm.h b/include/linux/mm.h index 0d4ee569aa6b..d01b296e7184 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4171,10 +4171,9 @@ int arch_lock_shadow_stack_status(struct task_struct= *t, unsigned long status); * DMA mapping IDs for page_pool * * When DMA-mapping a page, page_pool allocates an ID (from an xarray) and - * stashes it in the upper bits of page->pp_magic. We always want to be ab= le to - * unambiguously identify page pool pages (using page_pool_page_is_pp()). = Non-PP - * pages can have arbitrary kernel pointers stored in the same field as pp= _magic - * (since it overlaps with page->lru.next), so we must ensure that we cann= ot + * stashes it in the upper bits of page->pp_magic. Non-PP pages can have + * arbitrary kernel pointers stored in the same field as pp_magic (since + * it overlaps with page->lru.next), so we must ensure that we cannot * mistake a valid kernel pointer with any of the values we write into this * field. * @@ -4205,26 +4204,6 @@ int arch_lock_shadow_stack_status(struct task_struct= *t, unsigned long status); #define PP_DMA_INDEX_MASK GENMASK(PP_DMA_INDEX_BITS + PP_DMA_INDEX_SHIFT -= 1, \ PP_DMA_INDEX_SHIFT) =20 -/* Mask used for checking in page_pool_page_is_pp() below. page->pp_magic = is - * OR'ed with PP_SIGNATURE after the allocation in order to preserve bit 0= for - * the head page of compound page and bit 1 for pfmemalloc page, as well a= s the - * bits used for the DMA index. page_is_pfmemalloc() is checked in - * __page_pool_put_page() to avoid recycling the pfmemalloc page. - */ -#define PP_MAGIC_MASK ~(PP_DMA_INDEX_MASK | 0x3UL) - -#ifdef CONFIG_PAGE_POOL -static inline bool page_pool_page_is_pp(const struct page *page) -{ - return (page->pp_magic & PP_MAGIC_MASK) =3D=3D PP_SIGNATURE; -} -#else -static inline bool page_pool_page_is_pp(const struct page *page) -{ - return false; -} -#endif - #define PAGE_SNAPSHOT_FAITHFUL (1 << 0) #define PAGE_SNAPSHOT_PG_BUDDY (1 << 1) #define PAGE_SNAPSHOT_PG_IDLE (1 << 2) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 8d3fa3a91ce4..84247e39e9e7 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -933,6 +933,7 @@ enum pagetype { PGTY_zsmalloc =3D 0xf6, PGTY_unaccepted =3D 0xf7, PGTY_large_kmalloc =3D 0xf8, + PGTY_netpp =3D 0xf9, =20 PGTY_mapcount_underflow =3D 0xff }; @@ -1077,6 +1078,11 @@ PAGE_TYPE_OPS(Zsmalloc, zsmalloc, zsmalloc) PAGE_TYPE_OPS(Unaccepted, unaccepted, unaccepted) FOLIO_TYPE_OPS(large_kmalloc, large_kmalloc) =20 +/* + * Marks page_pool allocated pages. + */ +PAGE_TYPE_OPS(Netpp, netpp, netpp) + /** * PageHuge - Determine if the page belongs to hugetlbfs * @page: The page to test. diff --git a/include/net/netmem.h b/include/net/netmem.h index f7dacc9e75fd..3667334e16e7 100644 --- a/include/net/netmem.h +++ b/include/net/netmem.h @@ -298,7 +298,7 @@ static inline struct net_iov *__netmem_clear_lsb(netmem= _ref netmem) */ #define pp_page_to_nmdesc(p) \ ({ \ - DEBUG_NET_WARN_ON_ONCE(!page_pool_page_is_pp(p)); \ + DEBUG_NET_WARN_ON_ONCE(!PageNetpp(p)); \ __pp_page_to_nmdesc(p); \ }) =20 diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c index e5ff49f3425e..f771bb3e756d 100644 --- a/io_uring/zcrx.c +++ b/io_uring/zcrx.c @@ -444,6 +444,10 @@ static int io_zcrx_create_area(struct io_zcrx_ifq *ifq, area->freelist[i] =3D i; atomic_set(&area->user_refs[i], 0); niov->type =3D NET_IOV_IOURING; + + /* niov->pp is already initialized to NULL by + * kvmalloc_array(__GFP_ZERO). + */ } =20 area->free_count =3D nr_iovs; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d1d037f97c5f..2f6a55fab942 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1042,7 +1042,6 @@ static inline bool page_expected_state(struct page *p= age, #ifdef CONFIG_MEMCG page->memcg_data | #endif - page_pool_page_is_pp(page) | (page->flags & check_flags))) return false; =20 @@ -1069,8 +1068,6 @@ static const char *page_bad_reason(struct page *page,= unsigned long flags) if (unlikely(page->memcg_data)) bad_reason =3D "page still charged to cgroup"; #endif - if (unlikely(page_pool_page_is_pp(page))) - bad_reason =3D "page_pool leak"; return bad_reason; } =20 @@ -1379,9 +1376,11 @@ __always_inline bool free_pages_prepare(struct page = *page, mod_mthp_stat(order, MTHP_STAT_NR_ANON, -1); folio->mapping =3D NULL; } - if (unlikely(page_has_type(page))) + if (unlikely(page_has_type(page))) { + WARN_ON_ONCE(PageNetpp(page)); /* Reset the page_type (which overlays _mapcount) */ page->page_type =3D UINT_MAX; + } =20 if (is_check_pages_enabled()) { if (free_page_is_bad(page)) diff --git a/net/core/devmem.c b/net/core/devmem.c index b3a62ca0df65..40e7a4ec9009 100644 --- a/net/core/devmem.c +++ b/net/core/devmem.c @@ -285,6 +285,7 @@ net_devmem_bind_dmabuf(struct net_device *dev, niov =3D &owner->area.niovs[i]; niov->type =3D NET_IOV_DMABUF; niov->owner =3D &owner->area; + niov->pp =3D NULL; page_pool_set_dma_addr_netmem(net_iov_to_netmem(niov), net_devmem_get_dma_addr(niov)); if (direction =3D=3D DMA_TO_DEVICE) diff --git a/net/core/netmem_priv.h b/net/core/netmem_priv.h index cd95394399b4..4b90332d6c64 100644 --- a/net/core/netmem_priv.h +++ b/net/core/netmem_priv.h @@ -8,21 +8,18 @@ static inline unsigned long netmem_get_pp_magic(netmem_re= f netmem) return __netmem_clear_lsb(netmem)->pp_magic & ~PP_DMA_INDEX_MASK; } =20 -static inline void netmem_or_pp_magic(netmem_ref netmem, unsigned long pp_= magic) -{ - __netmem_clear_lsb(netmem)->pp_magic |=3D pp_magic; -} - -static inline void netmem_clear_pp_magic(netmem_ref netmem) -{ - WARN_ON_ONCE(__netmem_clear_lsb(netmem)->pp_magic & PP_DMA_INDEX_MASK); - - __netmem_clear_lsb(netmem)->pp_magic =3D 0; -} - static inline bool netmem_is_pp(netmem_ref netmem) { - return (netmem_get_pp_magic(netmem) & PP_MAGIC_MASK) =3D=3D PP_SIGNATURE; + /* Use ->pp for net_iov to identify if it's pp, which requires + * that non-pp net_iov should have ->pp NULL'd. + */ + if (netmem_is_net_iov(netmem)) + return !!__netmem_clear_lsb(netmem)->pp; + + /* For system memory, page type bit in struct page can be used + * to identify if it's pp. + */ + return PageNetpp(__netmem_to_page(netmem)); } =20 static inline void netmem_set_pp(netmem_ref netmem, struct page_pool *pool) diff --git a/net/core/page_pool.c b/net/core/page_pool.c index 05e2e22a8f7c..37eeab76c41c 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -654,7 +654,6 @@ s32 page_pool_inflight(const struct page_pool *pool, bo= ol strict) void page_pool_set_pp_info(struct page_pool *pool, netmem_ref netmem) { netmem_set_pp(netmem, pool); - netmem_or_pp_magic(netmem, PP_SIGNATURE); =20 /* Ensuring all pages have been split into one fragment initially: * page_pool_set_pp_info() is only called once for every page when it @@ -665,12 +664,19 @@ void page_pool_set_pp_info(struct page_pool *pool, ne= tmem_ref netmem) page_pool_fragment_netmem(netmem, 1); if (pool->has_init_callback) pool->slow.init_callback(netmem, pool->slow.init_arg); + + /* If it's page-backed */ + if (!netmem_is_net_iov(netmem)) + __SetPageNetpp(__netmem_to_page(netmem)); } =20 void page_pool_clear_pp_info(netmem_ref netmem) { - netmem_clear_pp_magic(netmem); netmem_set_pp(netmem, NULL); + + /* If it's page-backed */ + if (!netmem_is_net_iov(netmem)) + __ClearPageNetpp(__netmem_to_page(netmem)); } =20 static __always_inline void __page_pool_release_netmem_dma(struct page_poo= l *pool, base-commit: 54efec8782214652b331c50646013f8526570e8d --=20 2.17.1