From nobody Sun Feb 8 21:46:54 2026 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 AF5A6C001DE for ; Fri, 14 Jul 2023 16:18:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236247AbjGNQSK (ORCPT ); Fri, 14 Jul 2023 12:18:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48452 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236296AbjGNQRt (ORCPT ); Fri, 14 Jul 2023 12:17:49 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id F3B0535B3 for ; Fri, 14 Jul 2023 09:17:46 -0700 (PDT) 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 9EB8E1576; Fri, 14 Jul 2023 09:18:28 -0700 (PDT) Received: from e125769.cambridge.arm.com (e125769.cambridge.arm.com [10.1.196.26]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 527963F740; Fri, 14 Jul 2023 09:17:44 -0700 (PDT) From: Ryan Roberts To: Andrew Morton , Matthew Wilcox , "Kirill A. Shutemov" , Yin Fengwei , David Hildenbrand , Yu Zhao , Catalin Marinas , Will Deacon , Anshuman Khandual , Yang Shi , "Huang, Ying" , Zi Yan , Luis Chamberlain Cc: Ryan Roberts , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v3 2/4] mm: Default implementation of arch_wants_pte_order() Date: Fri, 14 Jul 2023 17:17:31 +0100 Message-Id: <20230714161733.4144503-2-ryan.roberts@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230714160407.4142030-1-ryan.roberts@arm.com> References: <20230714160407.4142030-1-ryan.roberts@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" arch_wants_pte_order() can be overridden by the arch to return the preferred folio order for pte-mapped memory. This is useful as some architectures (e.g. arm64) can coalesce TLB entries when the physical memory is suitably contiguous. The first user for this hint will be FLEXIBLE_THP, which aims to allocate large folios for anonymous memory to reduce page faults and other per-page operation costs. Here we add the default implementation of the function, used when the architecture does not define it, which returns -1, implying that the HW has no preference. In this case, mm will choose it's own default order. Signed-off-by: Ryan Roberts Reviewed-by: Yin Fengwei Reviewed-by: Yu Zhao --- include/linux/pgtable.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 5063b482e34f..2a1d83775837 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -313,6 +313,19 @@ static inline bool arch_has_hw_pte_young(void) } #endif =20 +#ifndef arch_wants_pte_order +/* + * Returns preferred folio order for pte-mapped memory. Must be in range [= 0, + * PMD_SHIFT-PAGE_SHIFT) and must not be order-1 since THP requires large = folios + * to be at least order-2. Negative value implies that the HW has no prefe= rence + * and mm will choose it's own default order. + */ +static inline int arch_wants_pte_order(void) +{ + return -1; +} +#endif + #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long address, --=20 2.25.1