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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 516DDC433E2 for ; Thu, 3 Sep 2020 16:59:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3622F20716 for ; Thu, 3 Sep 2020 16:59:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728419AbgICQ67 (ORCPT ); Thu, 3 Sep 2020 12:58:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:37338 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726678AbgICQ66 (ORCPT ); Thu, 3 Sep 2020 12:58:58 -0400 Received: from gaia (unknown [46.69.195.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A11F9206A5; Thu, 3 Sep 2020 16:58:56 +0000 (UTC) Date: Thu, 3 Sep 2020 17:58:54 +0100 From: Catalin Marinas To: Anshuman Khandual Cc: linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, will@kernel.org, akpm@linux-foundation.org, Mark Rutland , Marc Zyngier , Suzuki Poulose , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] arm64/mm: Enable THP migration Message-ID: <20200903165853.GD31409@gaia> References: <1597655984-15428-1-git-send-email-anshuman.khandual@arm.com> <1597655984-15428-3-git-send-email-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1597655984-15428-3-git-send-email-anshuman.khandual@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 17, 2020 at 02:49:44PM +0530, Anshuman Khandual wrote: > 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 s/HP/THP/ > 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 | 5 +++++ > 2 files changed, 9 insertions(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 6d232837cbee..e21b94061780 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -1876,6 +1876,10 @@ 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 7aa69cace784..c54334bca4e2 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -875,6 +875,11 @@ 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) }) > +#define __swp_entry_to_pmd(swp) __pmd((swp).val) > +#endif /* CONFIG_ARCH_ENABLE_THP_MIGRATION */ Reviewed-by: Catalin Marinas