From patchwork Fri Jul 14 16:17:31 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ryan Roberts X-Patchwork-Id: 13313840 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AEF04EB64DC for ; Fri, 14 Jul 2023 16:18:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=5YMBXBDNeqR2wwKWiTT5eGbyBdQCcfkAQysdlMYgRRY=; b=32rM0osxxnU6+I LRxfLs0vvXxRlwAC0cNVnhZPniXvbSUQs9Xm7LeUODvhLhQ1DlYhrj3kdv1X9DJynz4wQPLMveNoy wejCIxXCgpl5qwwXm0nOeqK5EkEyKQhog4l+/YIqLBWs/egxXD4iikl36pQpjkaD98o6kSd4NXbcg 1y1R48UvkCMvCIzi7pTLEm47Cy3GIjMmiHWtA5wpgUf5YHSPl5Kvvp26s+RGM/hYUyZYogGcftzDB Bs5tACGMiiyQMVVeLLRfh8rgaGccLoHLONphNMrdK9v1tqXcil2DlN4QzLmTLVQakw/LPzbn4TRv+ RAqaiTpPEvO527/utIuA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qKLUO-006crG-2p; Fri, 14 Jul 2023 16:17:52 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qKLUL-006cnE-0T for linux-arm-kernel@lists.infradead.org; Fri, 14 Jul 2023 16:17:50 +0000 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230714_091749_230696_F9D06193 X-CRM114-Status: GOOD ( 11.58 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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: Yu Zhao Reviewed-by: Yin Fengwei --- 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 +#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 preference + * 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,