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 D4283E75433 for ; Tue, 3 Oct 2023 07:32:38 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 077BA6B01B3; Tue, 3 Oct 2023 03:32:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 027476B01F0; Tue, 3 Oct 2023 03:32:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E31276B01F1; Tue, 3 Oct 2023 03:32:37 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id D05F66B01B3 for ; Tue, 3 Oct 2023 03:32:37 -0400 (EDT) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id A6094B37B3 for ; Tue, 3 Oct 2023 07:32:37 +0000 (UTC) X-FDA: 81303332754.20.6846120 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf16.hostedemail.com (Postfix) with ESMTP id 95D7C18000F for ; Tue, 3 Oct 2023 07:32:35 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=none; spf=pass (imf16.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1696318356; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FVpaoZVlYC0SQsn3P6GvLjvnV4rdyJlVcXP8PuYK2TU=; b=3KdgFMv5qFK7Q3h1oV4OMmoAwAwbx3e8Cg/Wy60+hWx76xT3MhmFYqt33bXjkJozV1EJA6 o3qeSXY1MNsVTqhtB+6GVTz0IyVVJuicSf6YyBbwR4iRZhfGdSxYDkKpWO1vo3CSPm9W5L qAPW0ZCrlQPAy+7yOg8nVDXsBT9975k= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1696318356; a=rsa-sha256; cv=none; b=fVyirPW5Gn1VHoT/QFwfdYo/gDjz2V35MQVcRo8tHpnI7OyyW8NMpy4RijFU4o/Rxzd0ut 4HvKd6nhNK/awhC15EUKnApZZMhUCEMXFaAKB/qoGhmhvxTKSvEvoyxWCsh+Qy0f0+yL51 8oLdcMe58fsDSPzhsTL0n87fxlyaBDs= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=none; spf=pass (imf16.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com; dmarc=pass (policy=none) header.from=arm.com 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 C668DC15; Tue, 3 Oct 2023 00:33:12 -0700 (PDT) Received: from [10.57.66.79] (unknown [10.57.66.79]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4E17F3F59C; Tue, 3 Oct 2023 00:32:31 -0700 (PDT) Message-ID: <0fb0840f-02f0-4103-a6be-eeb4fcc16f8f@arm.com> Date: Tue, 3 Oct 2023 08:32:29 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 7/9] arm64/mm: Override arch_wants_pte_order() Content-Language: en-GB To: Catalin Marinas 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 References: <20230929114421.3761121-1-ryan.roberts@arm.com> <20230929114421.3761121-8-ryan.roberts@arm.com> From: Ryan Roberts In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 95D7C18000F X-Rspam-User: X-Stat-Signature: h5jcyyqbwjqt5qcbscjoasy5oxp9gojh X-Rspamd-Server: rspam03 X-HE-Tag: 1696318355-993022 X-HE-Meta: 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 hPXnoBIj guhYMnHxTV7SMDirKXIQ2hHbhE2LBR48szgsCMFuTSpbQMqquCjuV/5k0Zbluiey52307jGmaEWwbsn46+bUfr6RJTuBKlCj0YPA9MOBGmhvl2Y65a6LeNkDQ02miJu5hzuZgzmHDIRdHx0giygpUnSylVdhkwNc1vft5CQK6Nqy1Mc3loUmP7sb2yyT7UPKc6t/RIIBD6amy91ObsI1FjE4ReLWsSOInzgHrHOE7Nm1k+UMa53GVdBGcAiFxr2cxH/w1IVrdtb35h00k9nuQ4Dc/2JCpt2Y5L1rSoBaZPqWxyLlPfS0A7pn0XxHjFvwI/FmSHn5te2r510et7H2N2GweOwYtMs3Glh2a 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 02/10/2023 16:21, Catalin Marinas wrote: > On Fri, Sep 29, 2023 at 12:44:18PM +0100, Ryan Roberts wrote: >> Define an arch-specific override of arch_wants_pte_order() so that when >> anon_orders=recommend is set, large folios will be allocated for >> anonymous memory with an order that is compatible with arm64's HPA uarch >> feature. >> >> Reviewed-by: Yu Zhao >> Signed-off-by: Ryan Roberts > > Acked-by: Catalin Marinas > >> 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). This is just a hangover from the "MVP" approach that I was persuing in v5, where we didn't want to configure too many orders for fear of fragmentation. But in v6 I've introduced UABI to configure the set of orders, and this function feeds into the special "recommend" set. So I think it is appropriate that this API allows expression of multiple orders as you suggest. 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.