From patchwork Mon Jul 31 17:03:03 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vishal Moola X-Patchwork-Id: 13335158 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 53CB0C04E69 for ; Mon, 31 Jul 2023 17:04:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233824AbjGaRE0 (ORCPT ); Mon, 31 Jul 2023 13:04:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59004 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233683AbjGaRD6 (ORCPT ); Mon, 31 Jul 2023 13:03:58 -0400 Received: from mail-oi1-x236.google.com (mail-oi1-x236.google.com [IPv6:2607:f8b0:4864:20::236]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A7BA1210E; Mon, 31 Jul 2023 10:03:43 -0700 (PDT) Received: by mail-oi1-x236.google.com with SMTP id 5614622812f47-3a426e70575so2742160b6e.0; Mon, 31 Jul 2023 10:03:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1690823022; x=1691427822; 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=Z39OytypuZQhWkFCV+z6u8l5O5ZgTP/vsQXKA5JsO6g=; b=U7jETlvh8mqc3055+tBC6M+9Gy8R7REEMm1ZwKGc87m0rGDIJvgZcQ22vsmsinFtgt YTQlnuPzwi5zjdD+hLDWvxB/bmYZ8keXNmrVzrv6YRz6eCv0CI9nx19KksxH7KprzagR irj90f/wH/tTIxD8sQn1Ka9sOZ4dPOYQtK8h3N0b0riSaIJ2B+2YXCtlZtVEkrPg3Bbm Ojw5AwhfC3mD3DUjG5dFAv5YKIY2ngXsFAsSD6uydkdJ8uV+q2q9uUnnFZIrFIqfANGz oTPiE5dBvTDG/Pv3tzLP875t1DoqUqRhJ+2aPTfRbOK8xixubum5W0ZiIgU8cUKgztEJ 6Kvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690823022; x=1691427822; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Z39OytypuZQhWkFCV+z6u8l5O5ZgTP/vsQXKA5JsO6g=; b=MxmwkpIAupiC1F2vgq0wuGUqKFjVP9kWb+Vu4tL1rsxcWeerwJj9QeJ2JR8iJvhXco CgS2dlm1zThJijEUzfz+/LpS5Bo4G1fvK6JDalyaWTgUYfsduHz3GaK7jZTfFZklO3BG bu+CdijTqQzXyCoApwBEZxfOp7LsZ7TKkhuMkqwIvsroNuX74iu8/LPRA/LF9DQFfXOk v8Yjg/iKuidEypBQ6Dk6yx0wyN3dBuFd48CbxlsyJX5Y6pAAJT3me6fbFgOS6oNyA/kX hbMlTEOXBQw7FYox7IdWDrtQZhfKrAHLxMyYLPhxSS2gGsChK5qp9/X7zeUW7Boz+o3W JLQw== X-Gm-Message-State: ABy/qLaA4DRUL23x2fe9Ex0F3Su/unBepEb6NHf5mrOI1kVcqOiF97W4 sLeOVkE419Paa1XskahrphIc6/SzW3KY4A== X-Google-Smtp-Source: APBJJlHO94ah80UzwDXxBX9kkXsVAL3mPuWGcSVwu/SHGxcgeWhtI+EazxMnc09xov2z5IkvLaxhhA== X-Received: by 2002:a05:6808:13c1:b0:3a3:7612:28cd with SMTP id d1-20020a05680813c100b003a3761228cdmr11096736oiw.28.1690823021788; Mon, 31 Jul 2023 10:03:41 -0700 (PDT) Received: from unknowna0e70b2ca394.attlocal.net ([2600:1700:2f7d:1800::16]) by smtp.googlemail.com with ESMTPSA id x31-20020a25ac9f000000b00c832ad2e2eesm2511833ybi.60.2023.07.31.10.03.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 31 Jul 2023 10:03:41 -0700 (PDT) From: "Vishal Moola (Oracle)" 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 Subject: [PATCH mm-unstable v8 02/31] pgtable: Create struct ptdesc Date: Mon, 31 Jul 2023 10:03:03 -0700 Message-Id: <20230731170332.69404-3-vishal.moola@gmail.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230731170332.69404-1-vishal.moola@gmail.com> References: <20230731170332.69404-1-vishal.moola@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 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/pgtable.h | 71 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 5f36c055794b..1f92514d54b0 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -993,6 +993,77 @@ static inline void ptep_modify_prot_commit(struct vm_area_struct *vma, #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */ #endif /* CONFIG_MMU */ + +/** + * 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)); + /* * No-op macros that just return the current protection value. Defined here * because these macros can be used even if CONFIG_MMU is not defined.