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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E534E75426 for ; Tue, 3 Oct 2023 12:05:35 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7379D6B0124; Tue, 3 Oct 2023 08:05:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6C0CF6B0126; Tue, 3 Oct 2023 08:05:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 588D16B0175; Tue, 3 Oct 2023 08:05:35 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 479766B0124 for ; Tue, 3 Oct 2023 08:05:35 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id EEBAB1CA18B for ; Tue, 3 Oct 2023 12:05:34 +0000 (UTC) X-FDA: 81304020588.18.D45D8ED Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf14.hostedemail.com (Postfix) with ESMTP id D6B11100036 for ; Tue, 3 Oct 2023 12:05:32 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none); spf=pass (imf14.hostedemail.com: domain of cmarinas@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=cmarinas@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1696334733; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zzaBO66vi5SBS9J1N+VMxMm4ga5mTKjaapifhUTP8ME=; b=21M7gj95CsgzXnB9Mbw1x2hcHQyqva/+z3DQNdJJSmU2vyJX606QkuTyKOshoNW1zBqS2P FZeKeUW1nOdsKkJ1yxGgDHL/CZ3KvTAW3GN6kMUh/CDaesBJb9uSdteB0VuG+gB4VS9eel 02tPwUT3x5n+Unl5nbKwYWE868e62Eg= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none); spf=pass (imf14.hostedemail.com: domain of cmarinas@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=cmarinas@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1696334733; a=rsa-sha256; cv=none; b=Mxv0vukHyJaf0ujBYsY5rq5RCK8SsHSRAICU4FZw/xQnfbEMayRkmh88vJW1DE+HGGdGT5 VuPnXt/la9R19nSNqOutpEqrxK4+erBZRjsPn8iTJbhdaHCs8+Gxe4/ig8mGcY4vYIogXW HYHAChbmnC2F3w7vfeotxrGjoznxCuE= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 73FF5611C3; Tue, 3 Oct 2023 12:05:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B9032C433C8; Tue, 3 Oct 2023 12:05:27 +0000 (UTC) Date: Tue, 3 Oct 2023 13:05:25 +0100 From: Catalin Marinas To: Ryan Roberts Cc: Andrew Morton , Matthew Wilcox , Yin Fengwei , David Hildenbrand , Yu Zhao , Anshuman Khandual , Yang Shi , "Huang, Ying" , Zi Yan , Luis Chamberlain , Itaru Kitayama , "Kirill A. Shutemov" , John Hubbard , David Rientjes , Vlastimil Babka , Hugh Dickins , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v6 7/9] arm64/mm: Override arch_wants_pte_order() Message-ID: References: <20230929114421.3761121-1-ryan.roberts@arm.com> <20230929114421.3761121-8-ryan.roberts@arm.com> <0fb0840f-02f0-4103-a6be-eeb4fcc16f8f@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0fb0840f-02f0-4103-a6be-eeb4fcc16f8f@arm.com> X-Rspam-User: X-Stat-Signature: zmp5z9md7kgf1zuaxf1a76f6tjoqsrjx X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: D6B11100036 X-HE-Tag: 1696334732-873276 X-HE-Meta: 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 CcRWVide LYzLCXxk9naqs1pzqAssEQzeJg3uGGHMkj9ZrypcNpp1m0QlC20OQ4ugf9xO3jII3vyof8uFFYHAV61eUa7EIDv0W8xp2P4oMhiv4b/go7oZvFRVmuY89poUybFUHLQcMWk5S/sas7LhAtMXLE7XxiEFinhwonv1C5DZNzNRuUHeOx6IOp7lYgqROMNNiJPP6icLBZbj+9AZ2eD8OtxrLjqCGEJ+Gn4wNMocKKIsJrfdX2FHmZ8r5lUR1fZje9snoKZDb+KKBCiofINuXIjffHyt3HyIJbNHtuR0y8erj+NVRacz5IzsWXUvVVMaMTxJWh7vccb1mp7xRJyDj9y1jRTmhDF8bTNVMRaW11xPdC0baoSiD6hpau1Ga2ei1XONJLeY12xOXomWtq7eB88J47D2AMeffd1bRo6lG6bqa+LJflxVDLoIG5GCukquLLKk4W/RL X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Oct 03, 2023 at 08:32:29AM +0100, Ryan Roberts wrote: > On 02/10/2023 16:21, Catalin Marinas wrote: > > On Fri, Sep 29, 2023 at 12:44:18PM +0100, Ryan Roberts wrote: > >> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > >> index 7f7d9b1df4e5..e3d2449dec5c 100644 > >> --- a/arch/arm64/include/asm/pgtable.h > >> +++ b/arch/arm64/include/asm/pgtable.h > >> @@ -1110,6 +1110,16 @@ extern pte_t ptep_modify_prot_start(struct vm_area_struct *vma, > >> extern void ptep_modify_prot_commit(struct vm_area_struct *vma, > >> unsigned long addr, pte_t *ptep, > >> pte_t old_pte, pte_t new_pte); > >> + > >> +#define arch_wants_pte_order arch_wants_pte_order > >> +static inline int arch_wants_pte_order(void) > >> +{ > >> + /* > >> + * Many arm64 CPUs support hardware page aggregation (HPA), which can > >> + * coalesce 4 contiguous pages into a single TLB entry. > >> + */ > >> + return 2; > >> +} > > > > I haven't followed the discussions on previous revisions of this series > > but I wonder why not return a bitmap from arch_wants_pte_order(). For > > arm64 we may want an order 6 at some point (contiguous ptes) with a > > fallback to order 2 as the next best. > > This sounds like good idea to me - I'll implement it, assuming there is a next > rev. (Or in the unlikely event that this is the only pending change, I'd rather > defer it to when we actually need it with the contpte series). Fine by me, at the moment there wouldn't be any user, so a patch on top later would do. > Side note: I don't think order-6 is ever a contpte size? Its order-4 for 4K, > order-7 for 16k and order-5 for 64k. Yes, it's order-4 for 4K pages (I was thinking too much of the "64" in 64KB). -- Catalin