From nobody Sun Oct 5 23:45:01 2025 Received: from invmail4.hynix.com (exvmail4.skhynix.com [166.125.252.92]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 20723223335; Mon, 28 Jul 2025 08:20:20 +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=1753690827; cv=none; b=i7rxSz4i3JjJ5ThlIBRRF1LKPBIO3DCugzV6pFMZ9dlw+PfQC7J/ii6+m6v0817tymZ7RBYLmHP1q1Pzy7a5Qa735tAuSdQ4Wj1FpZiwlYeTUvcHGxIhQyzICimoN30f2QvmBRu92efjqs0iDNx1eFY23B0fNs20YtP/yk+ZxSg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753690827; c=relaxed/simple; bh=952470Bh2x0ElBhbqrd+qI3pgSq55U4sbWS7Uq/2cRg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; b=ug0Y/Dvj0Y3zrYfSqvYtU8Eqy1+IQ4tN0EMibe2OzhwN+0/suTjmxjZScwrXg0hYyb/W9bdKkKrZvx4RFJqUJDm+6Pq8U53vO2wQHwSRQsgiJ2+DiKliGaq7rqmicG+2eSjosg65FWrg2OJv9gdzffMWhherwFWkZWWNPIufUHI= 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-1a-688732c3f9fa 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 Subject: [PATCH v2 rebase as of Jul 28] mm, page_pool: introduce a new page type for page pool in page type Date: Mon, 28 Jul 2025 17:20:08 +0900 Message-Id: <20250728082008.34091-1-byungchul@sk.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20250728052742.81294-1-byungchul@sk.com> References: <20250728052742.81294-1-byungchul@sk.com> X-Brightmail-Tracker: H4sIAAAAAAAAAzWSa0hTcRjG+++cnXMcrg5T6qRQMenCpDSxes0IMag/hFD0JTKokYe2vI15 SaPLUtGSXFIZpQu2TJ2Xsma5KWq1LdOiknlhdvGySrp4KTVvs2xN+vbjfX7P8+llCMkYGcAo k1J5dZI8QUqJSNGIr2GjLSxPEWrWLQVdbQ0F1TMZUDFgEYKuqh7B5Ow7GhaaWxFM2J9T8N02 jqDUMEWA7k0OCb9q5wj43OqiodoUA/3lQyQ05ZkJcF1uo6Agx01A8+woDVkWowB0dRoaOuq1 Qrg2V0aAWTNAQ2ejjoK+mgUhDFkLSGgvriThR5GdgH5tFLTql8PUy2EE9lqzAKYu3aKg+2aj AK469BR8zOlH4LC5SCiav0BByXktAveMZ220cFIIJc/66CgZtg2PEfhhZa8AO1teCHBD8Qca 601puM4ow/lOB4FNVRcpbBq/QuP3PU0UbrvhJnHDYARusEwIcEH2KIV/fn5L4rGWbmqf3yHR jjg+QZnOq0N2HhUpCt02QjW9P6PZwGvQp+h85MNwbDh3zzAk/M+/dTYvU+x6zumcJf6xPxvK GYsmPSxiCPYhzdXUOr2BHxvPafsrvQWSXctVPDB7Wcxu4TTuV4LF0dVc9f0nXt+H3cpVtP/x OhKP05A1TS46ZQzXOKhe5JXcU6OTLERiPVpShSTKpPREuTIhfJMiM0mZselYcqIJed6g/Mx8 rAWNdxywIpZBUl/xl225ColQnp6SmWhFHENI/cWqMs9JHCfPPMWrk4+o0xL4FCsKZEjpCnHY 1Mk4CXtcnsrH87yKV/9PBYxPgAbdGVqoGfk4H3m4LXl7z5t410hacJeq+va6XY8MRV1Wvw2r ItqD9/aqHkfpZT+T3crru/0U0THOcw7lMp+Q3kjjuRNpedldgb6J/gXP7EHdnfLTmTsrcl27 Y3Uo6Kzp0d0InBH57TAtazlqfm2esFu0w47GNS/2Or6W1u+pMx6sF0vJFIV8s4xQp8j/Anxe LVYCAwAA X-Brightmail-Tracker: H4sIAAAAAAAAAzWRa0hTcRjG/e+cnbONJodlddIPwSAGRmZR+UYRXelP0A2EKJBaeWhLN8em MoNi5ciKXCszSpdNSuemZS2bl1Jkm6sl3WbWuk7tQpGpuaXp7LIWffvxPr/n+fIKCEmATBYo 1fmcVi3PlVIiUrR5efF896ISRXqXC8DS2EBB/Q892Ppa+GBxuBBEJl7R8LvdhyDsvUvBF88o gsvVYwRYHhlJ+N44ScAH3wAN9c5NEKr9SMKdkmYCBk7do6DUGCWgfWKIhiMtdTyw3DTQ4Lno 58Njl4kPZydrCGg29NHQ02ah4G3Dbz58dJeS4K+wkzBS7iUgZFoFPutMGOseROBtbObB2MmL FPReaONBWcBKwTtjCEHAM0BC+dQxCioPmxBEf8TWhswRPlR2vaVXzcOewWECN9lf8HCw4z4P t1a8obHVWYBv1qXiE8EAgZ2O4xR2jp6h8etndyh873yUxK39y3BrS5iHS4uHKPztw0sSD3f0 UluTdopWZHO5ykJOu2DlbpHCHPUQmvFt+vZqzoDerzmBhAKWWcz+tHj4f5liZGwwOEH85SQm na0rj8RYJCCYJpptaAzGg+lMDmsK2eMFkpnL2m40x1nMLGEN0Qe8f6Nz2PrrnXFfyCxlbf5f cUcSc1qPjJNmJLKiBAdKUqoLVXJl7pI0XY6iSK3Up+3NUzlR7NO1B6dOt6BIzwY3YgRIOk38 KeOoQsKXF+qKVG7ECghpklhTEzuJs+VFBzht3i5tQS6nc6MUASmdJd64ndstYfbJ87kcjtNw 2v8pTyBMNqC0gWjWmS94jl6onbFuvyzTYc/yLht5nulre9pruzW23vUs5XZJvezkZ+naSmL2 CrlR5thYd727yXzWHEhMdIRMq88llnVem5VcHN7RY0yIqisaFrV7XTeudrsKrnzN7O9Kq+oO 75EKD9lVpq1PHo769VsuVdGadxmvtujLCkuXS0mdQr4wldDq5H8AhTp9/OUCAAA= 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" Rebasing on the latest linux-next/master is required. Otherwise, a build fail is observed. Sorry about the noise. 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 . Reviewed-by: Mina Almasry Suggested-by: David Hildenbrand ---8<--- From 26c9a731f388b788d6ea972c313bc8da8831412b Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Mon, 28 Jul 2025 17:09:20 +0900 Subject: [PATCH v2 rebase as of Jul 28] 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 Signed-off-by: Byungchul Park --- .../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 | 1 + 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, 34 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..4cceb97ca26a 100644 --- a/io_uring/zcrx.c +++ b/io_uring/zcrx.c @@ -444,6 +444,7 @@ 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 =3D NULL; } =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..0a10f3026faa 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 (netmem_is_net_iov(netmem)) + return; + __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 (netmem_is_net_iov(netmem)) + return; + __ClearPageNetpp(__netmem_to_page(netmem)); } =20 static __always_inline void __page_pool_release_netmem_dma(struct page_poo= l *pool, base-commit: 0b90c3b6d76ea512dc3dac8fb30215e175b0019a --=20 2.17.1