From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0DC4BC433E2 for ; Mon, 15 Jun 2020 13:15:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E10152074D for ; Mon, 15 Jun 2020 13:15:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730381AbgFONPk (ORCPT ); Mon, 15 Jun 2020 09:15:40 -0400 Received: from foss.arm.com ([217.140.110.172]:47626 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729977AbgFONPj (ORCPT ); Mon, 15 Jun 2020 09:15:39 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A6C2031B; Mon, 15 Jun 2020 06:15:38 -0700 (PDT) Received: from p8cg001049571a15.arm.com (unknown [10.163.79.186]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 2D45C3F6CF; Mon, 15 Jun 2020 06:15:34 -0700 (PDT) From: Anshuman Khandual To: linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org Cc: catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, ziy@nvidia.com, Anshuman Khandual , Marc Zyngier , Suzuki Poulose , linux-kernel@vger.kernel.org Subject: [RFC V2 2/2] arm64/mm: Enable THP migration Date: Mon, 15 Jun 2020 18:45:18 +0530 Message-Id: <1592226918-26378-3-git-send-email-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1592226918-26378-1-git-send-email-anshuman.khandual@arm.com> References: <1592226918-26378-1-git-send-email-anshuman.khandual@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In certain page migration situations, a THP page can be migrated without being split into it's constituent subpages. This saves time required to split a THP and put it back together when required. But it also saves an wider address range translation covered by a single TLB entry, reducing future page fault costs. A previous patch changed platform THP helpers per generic memory semantics, clearing the path for THP migration support. This adds two more THP helpers required to create PMD migration swap entries. Now just enable HP migration via ARCH_ENABLE_THP_MIGRATION. Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Rutland Cc: Marc Zyngier Cc: Suzuki Poulose Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual --- arch/arm64/Kconfig | 4 ++++ arch/arm64/include/asm/pgtable.h | 10 ++++++++++ 2 files changed, 14 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 31380da53689..01d432dc813e 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1874,6 +1874,10 @@ config ARCH_ENABLE_HUGEPAGE_MIGRATION def_bool y depends on HUGETLB_PAGE && MIGRATION +config ARCH_ENABLE_THP_MIGRATION + def_bool y + depends on TRANSPARENT_HUGEPAGE + menu "Power management options" source "kernel/power/Kconfig" diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 560be593a8dc..892c30129cd2 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -907,6 +907,16 @@ static inline pmd_t pmdp_establish(struct vm_area_struct *vma, #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) }) #define __swp_entry_to_pte(swp) ((pte_t) { (swp).val }) +#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION +#define __pmd_to_swp_entry(pmd) ((swp_entry_t) { pmd_val(pmd) }) + +/* + * pmd_present() must return false for a swap PMD entry. + * Just explicitly clear PMD_TABLE_BIT while converting. + */ +#define __swp_entry_to_pmd(swp) __pmd((swp).val & ~PMD_TABLE_BIT) +#endif /* CONFIG_ARCH_ENABLE_THP_MIGRATION */ + /* * Ensure that there are not more swap files than can be encoded in the kernel * PTEs. -- 2.20.1