From patchwork Mon Jun 12 21:03:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vishal Moola X-Patchwork-Id: 13277501 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 E67CDCA9EB0 for ; Mon, 12 Jun 2023 21:08:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239066AbjFLVIL (ORCPT ); Mon, 12 Jun 2023 17:08:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238870AbjFLVHx (ORCPT ); Mon, 12 Jun 2023 17:07:53 -0400 Received: from mail-oa1-x35.google.com (mail-oa1-x35.google.com [IPv6:2001:4860:4864:20::35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 18C1A1720; Mon, 12 Jun 2023 14:04:55 -0700 (PDT) Received: by mail-oa1-x35.google.com with SMTP id 586e51a60fabf-19f30256921so3580454fac.1; Mon, 12 Jun 2023 14:04:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1686603894; x=1689195894; 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=ljdqluisjsw1T2S09X4eHyFy2qx+wqxffRAjzd8Lr/M=; b=kXhs64xMe2DVLtVyKP8s5V9ZG7303479O9N/ToVEDXv1Gbm2sbmI/fCFK4uGChjd81 H6kVjd8TOmWAnbLRs4zxfvez/oEYXs2XwY0nLHoNXXHUhU8y7b7V442KEyA9t5B9q0Uq 4QLgvZ36Wl/+n0Pso7S7rQM028p+NfGQr9Yw1FiqoIIWOMPYwEq7/a7S5+qCahfgFwfk /tBZy6zuFg7ypVrVCmXYQ0dxFeVbbzBl8iAc+EUXGUcIwns5danLCJs4qv8DZQXG/O2x E2z06iVumBlee2giB3swtpcGSjTtcpgqJNat/RjdgRm72hK9QqxESqcl6ywJsUBEizO2 9nAQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686603894; x=1689195894; 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=ljdqluisjsw1T2S09X4eHyFy2qx+wqxffRAjzd8Lr/M=; b=kMxaRtXPYfzy2z5KvAa5xyrFZABIyctY198WtRY3Ou753pR9EPkuYFT5AWff80aEhP 7vGRbPgOsW4Q4uKZ5N4xho0SFaJzqRy7NjYFav1rqTOkT8NbtPD7pl3TgJrwmNrD7N47 EqTOoKBXrdCtlforf5sKX0wct2b8IoWhd/74NtaUsWxoB8pHNPCGcea++gJEE18+oJkt OucNBTIWOoHfZPDq5P/CTxa54GJguu1c6ngLXa62Juju6ZFFy/JeBU+wZC3ppWmBW8p+ XZ5x4BCvwzVdpZ8RRSPUVPyerdtQXLyZXy2rpjXqcluToWOfYdMnb0yVr/M6KxlguBZw 6wNw== X-Gm-Message-State: AC+VfDw2W7fmHcoRRcKfXl2iv1apBCkSzUmgtthy2XghKYsZ3HpypCDi PmIrImXi28+lEZIcMCFNTX8= X-Google-Smtp-Source: ACHHUZ6qMtsAIJRXZ8Ey4kYlwwJ6x1NqBtbJDNBqsW5hbZHAQ7e3oNYyd6EZmRmybOQvyHBLsoezFA== X-Received: by 2002:a05:6871:3d1:b0:1a6:5818:f224 with SMTP id a17-20020a05687103d100b001a65818f224mr4571226oag.40.1686603894310; Mon, 12 Jun 2023 14:04:54 -0700 (PDT) Received: from unknowna0e70b2ca394.attlocal.net ([2600:1700:2f7d:1800::16]) by smtp.googlemail.com with ESMTPSA id s125-20020a817783000000b00569eb609458sm2757115ywc.81.2023.06.12.14.04.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Jun 2023 14:04:54 -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)" Subject: [PATCH v4 04/34] pgtable: Create struct ptdesc Date: Mon, 12 Jun 2023 14:03:53 -0700 Message-Id: <20230612210423.18611-5-vishal.moola@gmail.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230612210423.18611-1-vishal.moola@gmail.com> References: <20230612210423.18611-1-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 | 51 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index c5a51481bbb9..330de96ebfd6 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -975,6 +975,57 @@ 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; + }; + +#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.