From patchwork Wed May 31 21:30:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vishal Moola X-Patchwork-Id: 13262631 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 46625C7EE43 for ; Wed, 31 May 2023 21:32:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230375AbjEaVb3 (ORCPT ); Wed, 31 May 2023 17:31:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230061AbjEaVbZ (ORCPT ); Wed, 31 May 2023 17:31:25 -0400 Received: from mail-yw1-x1132.google.com (mail-yw1-x1132.google.com [IPv6:2607:f8b0:4864:20::1132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5017D18B; Wed, 31 May 2023 14:31:18 -0700 (PDT) Received: by mail-yw1-x1132.google.com with SMTP id 00721157ae682-568ba7abc11so705557b3.3; Wed, 31 May 2023 14:31:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1685568677; x=1688160677; 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=/2bE9CDG9Oxw3pEA2fSuUshC33VMwoQ2Xz6qScjQL3E=; b=iYqqA4KZmoroGYhynV/jiNkWzAMHN4TlFNnsupyXM0HztFgnmGpbYhflGvCI4PnTEH qsb+x4h+Ra/DHJZpmJ+cDpCt0WFO8DN9RsHpGbhgd8UZD1C59aXCIdDYpdL/DDlqjtME QAC1ynKbnXEL2BUoeiDKJEOTEmjHPJwx20Oocm0d9VYWRam4vpslVsanNLIqZtenI7il z8Y4AX5Qo3hIFiKRtt14OfPeMVmgXXgQiLO70vbxlL1MgUQYvu/5R1IEb6sabFTUiQkk WKmmoKw4Cu+qJUco9/5c4L88Blpl8Ohrj5Udd50ZlUMrgKFkg8PwQhuutxVbJdY53ahQ RhOQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1685568677; x=1688160677; 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=/2bE9CDG9Oxw3pEA2fSuUshC33VMwoQ2Xz6qScjQL3E=; b=VyC2vVA9i0/W1KOTBLlTWbwoTRfLbnPFj1R7j9t+ixET+E21EtpII5IsRCAjHSD6aC +qcYmtVXhNu3XuJCSJprz7lZr1DkGHlFoAboorP5cMy+WxojrNEFvvyAHeZwWNj9pcG7 Y92O3/6YryTijdYoAHivDC2D8TGraPusRtF6XY5Hyfdu8IMaVF1FY1hNT6Q5r1PphYQU Kgqwbh9OzWgnR+SP4nHfVUPeRT2mzMqO3z4kdT3+ps0PKDb6ERWK2oBuP+aZRT2JNh5S xRGN1U9/xRaHRgFQZOixp6nboZ+a8cM9JmuoqJzk4VzjTVxssJjYQBPAa7riCiTFfYht IDOg== X-Gm-Message-State: AC+VfDwPw+mcJAit4hsVQmWXQE2zdpep5THriucgLF4BbqU1A4nyGshP fMqTeDKV8oW4SpzyDOEXoBc= X-Google-Smtp-Source: ACHHUZ6pTbgk5oakG8rCTNTHmfkc+dDnZpqxrm9LdrARtP0jWcbiwYUD1VVJhesMtUI+Yz5eprOqiQ== X-Received: by 2002:a0d:d816:0:b0:565:bb04:53fa with SMTP id a22-20020a0dd816000000b00565bb0453famr7385514ywe.10.1685568677391; Wed, 31 May 2023 14:31:17 -0700 (PDT) Received: from unknowna0e70b2ca394.attlocal.net ([2600:1700:2f7d:1800::46]) by smtp.googlemail.com with ESMTPSA id t63-20020a0dd142000000b0055aafcef659sm658905ywd.5.2023.05.31.14.31.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 31 May 2023 14:31:17 -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, "Vishal Moola (Oracle)" Subject: [PATCH v3 04/34] pgtable: Create struct ptdesc Date: Wed, 31 May 2023 14:30:02 -0700 Message-Id: <20230531213032.25338-5-vishal.moola@gmail.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230531213032.25338-1-vishal.moola@gmail.com> References: <20230531213032.25338-1-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) --- include/linux/pgtable.h | 52 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index c5a51481bbb9..c997e9878969 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -975,6 +975,58 @@ 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_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. + * @_pt_s390_gaddr: Aliases with page's mapping. Used for s390 gmap only. + * @pt_mm: Used for x86 pgds. + * @pt_frag_refcount: For fragmented page table tracking. Powerpc and s390 only. + * @ptl: Lock for the page table. + * + * 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 list_head pt_list; + struct { + unsigned long _pt_pad_1; + pgtable_t pmd_huge_pte; + }; + }; + unsigned long _pt_s390_gaddr; + + union { + struct mm_struct *pt_mm; + atomic_t pt_frag_refcount; + unsigned long index; + }; + +#if ALLOC_SPLIT_PTLOCKS + spinlock_t *ptl; +#else + spinlock_t ptl; +#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, _pt_s390_gaddr); +TABLE_MATCH(pt_mm, pt_mm); +TABLE_MATCH(ptl, ptl); +#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.