From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Vishal Moola (Oracle)" Subject: [PATCH mm-unstable v9 02/31] pgtable: create struct ptdesc Date: Mon, 7 Aug 2023 16:04:44 -0700 Message-ID: <20230807230513.102486-3-vishal.moola@gmail.com> References: <20230807230513.102486-1-vishal.moola@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=w2U+CoRZgWoyL3ZUwMuF7ubfAc3jmmjXma+QxKgBoxU=; b=0E0uH9omip9k0a kUjFr7/IUTJNeMfIRSCzES+6LQ6nBWfVmCUqI/Iw9xRZGGtGxaARTstUukr/NH3xMuLkzD8NOJghF eODTAOmLibEAvblcvADKARUvdWXAnzJqZKXnM8eCLnXpz3GGzaZOINMBbYYS3NRj//GxUYPn6RUnt CvHsBFdo1U1UmvnFKQEIS9JIbkZblwtQH+zFwmEBU1/Mlx4grx0ttgfPFJA4CAqH4QBZ8F3LNxMRB yuSCeRvRHYAZunYPMfPW6JJEZ4IvX5nD/ECq4ciP25OkT3X+HKXiQtkqZHJjPJpk3WE1+m87W5GZn yPTgdVDwyuypPF5HUIgA==; DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1691449522; x=1692054322; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=a34f21esV50lWBersDNDqmppsx1/6ilmHOTavl/xl8o=; b=oFwky5a0u6RDMZneanUwrrMHlk718vp357up6yt/zwnqVYFChL1rvBLlof3lNCzIMa fNsEK2lTF1AVBptjZ1CNiCZUzihavKETKYN9gVvYQI6adZVOr5WVilhYnG1hRIdUadMS rZHYG0cY0MgC9spT/xtrGp0Z9RSAR89ub11+qTFSD/NHXR1SOhgGi5SO3dghfFZLOejg KputLo/y59tBrGZ+oHkk/Miwz+ltthb0+dR9j85/GLscklo1srlDZt2wotLowv37n6A5 LO+9uJnrNQ6hj9u600MpE0S2h1+9c+75UpIga0Og5F4xShPF0bPK2EhAmwZTlcxr2oZQ 4pBQ== In-Reply-To: <20230807230513.102486-1-vishal.moola@gmail.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+glpr-linux-riscv=m.gmane-mx.org@lists.infradead.org To: Andrew Morton , Matthew Wilcox Cc: linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, loongarch@lists.linux.dev, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-openrisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, xen-devel@lists.xenproject.org, kvm@vger.kernel.org, Hugh Dickins , "Vishal Moola (Oracle)" , Mike Rapoport Currently, page table information is stored within struct page. As part of simplifying struct page, create struct ptdesc for page table information. Signed-off-by: Vishal Moola (Oracle) Acked-by: Mike Rapoport (IBM) --- include/linux/mm_types.h | 70 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 18c8c3d793b0..cb47438ae17f 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -397,6 +397,76 @@ FOLIO_MATCH(flags, _flags_2); FOLIO_MATCH(compound_head, _head_2); #undef FOLIO_MATCH +/** + * struct ptdesc - Memory descriptor for page tables. + * @__page_flags: Same as page flags. Unused for page tables. + * @pt_rcu_head: For freeing page table pages. + * @pt_list: List of used page tables. Used for s390 and x86. + * @_pt_pad_1: Padding that aliases with page's compound head. + * @pmd_huge_pte: Protected by ptdesc->ptl, used for THPs. + * @__page_mapping: Aliases with page->mapping. Unused for page tables. + * @pt_mm: Used for x86 pgds. + * @pt_frag_refcount: For fragmented page table tracking. Powerpc and s390 only. + * @_pt_pad_2: Padding to ensure proper alignment. + * @ptl: Lock for the page table. + * @__page_type: Same as page->page_type. Unused for page tables. + * @_refcount: Same as page refcount. Used for s390 page tables. + * @pt_memcg_data: Memcg data. Tracked for page tables here. + * + * This struct overlays struct page for now. Do not modify without a good + * understanding of the issues. + */ +struct ptdesc { + unsigned long __page_flags; + + union { + struct rcu_head pt_rcu_head; + struct list_head pt_list; + struct { + unsigned long _pt_pad_1; + pgtable_t pmd_huge_pte; + }; + }; + unsigned long __page_mapping; + + union { + struct mm_struct *pt_mm; + atomic_t pt_frag_refcount; + }; + + union { + unsigned long _pt_pad_2; +#if ALLOC_SPLIT_PTLOCKS + spinlock_t *ptl; +#else + spinlock_t ptl; +#endif + }; + unsigned int __page_type; + atomic_t _refcount; +#ifdef CONFIG_MEMCG + unsigned long pt_memcg_data; +#endif +}; + +#define TABLE_MATCH(pg, pt) \ + static_assert(offsetof(struct page, pg) == offsetof(struct ptdesc, pt)) +TABLE_MATCH(flags, __page_flags); +TABLE_MATCH(compound_head, pt_list); +TABLE_MATCH(compound_head, _pt_pad_1); +TABLE_MATCH(pmd_huge_pte, pmd_huge_pte); +TABLE_MATCH(mapping, __page_mapping); +TABLE_MATCH(pt_mm, pt_mm); +TABLE_MATCH(ptl, ptl); +TABLE_MATCH(rcu_head, pt_rcu_head); +TABLE_MATCH(page_type, __page_type); +TABLE_MATCH(_refcount, _refcount); +#ifdef CONFIG_MEMCG +TABLE_MATCH(memcg_data, pt_memcg_data); +#endif +#undef TABLE_MATCH +static_assert(sizeof(struct ptdesc) <= sizeof(struct page)); + /* * Used for sizing the vmemmap region on some architectures */ -- 2.40.1