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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF45AEB64D9 for ; Tue, 4 Jul 2023 12:36:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230389AbjGDMgp (ORCPT ); Tue, 4 Jul 2023 08:36:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231406AbjGDMgj (ORCPT ); Tue, 4 Jul 2023 08:36:39 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 4BFCAE7B for ; Tue, 4 Jul 2023 05:36:36 -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 1738F2F4; Tue, 4 Jul 2023 05:37:18 -0700 (PDT) Received: from [10.1.35.40] (C02Z41KALVDN.cambridge.arm.com [10.1.35.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0FC6E3F762; Tue, 4 Jul 2023 05:36:33 -0700 (PDT) Message-ID: <6d389825-1fc0-5c16-7858-2290fd632682@arm.com> Date: Tue, 4 Jul 2023 13:36:32 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [PATCH v2 3/5] mm: Default implementation of arch_wants_pte_order() To: Yu Zhao , "Yin, Fengwei" Cc: Andrew Morton , Matthew Wilcox , "Kirill A. Shutemov" , David Hildenbrand , Catalin Marinas , Will Deacon , Anshuman Khandual , Yang Shi , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20230703135330.1865927-1-ryan.roberts@arm.com> <20230703135330.1865927-4-ryan.roberts@arm.com> From: Ryan Roberts In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/07/2023 04:59, Yu Zhao wrote: > On Mon, Jul 3, 2023 at 9:02 PM Yu Zhao wrote: >> >> On Mon, Jul 3, 2023 at 8:23 PM Yin, Fengwei wrote: >>> >>> >>> >>> On 7/3/2023 9:53 PM, Ryan Roberts wrote: >>>> 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 the order corresponding >>>> to 64K. >>>> >>>> Signed-off-by: Ryan Roberts >>>> --- >>>> include/linux/pgtable.h | 13 +++++++++++++ >>>> 1 file changed, 13 insertions(+) >>>> >>>> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h >>>> index a661a17173fa..f7e38598f20b 100644 >>>> --- a/include/linux/pgtable.h >>>> +++ b/include/linux/pgtable.h >>>> @@ -13,6 +13,7 @@ >>>> #include >>>> #include >>>> #include >>>> +#include >>>> >>>> #if 5 - defined(__PAGETABLE_P4D_FOLDED) - defined(__PAGETABLE_PUD_FOLDED) - \ >>>> defined(__PAGETABLE_PMD_FOLDED) != CONFIG_PGTABLE_LEVELS >>>> @@ -336,6 +337,18 @@ 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. >>>> + */ >>>> +static inline int arch_wants_pte_order(struct vm_area_struct *vma) >>>> +{ >>>> + return ilog2(SZ_64K >> PAGE_SHIFT); >>> Default value which is not related with any silicon may be: PAGE_ALLOC_COSTLY_ORDER? >>> >>> Also, current pcp list support cache page with order 0...PAGE_ALLOC_COSTLY_ORDER, 9. >>> If the pcp could cover the page, the pressure to zone lock will be reduced by pcp. >> >> The value of PAGE_ALLOC_COSTLY_ORDER is reasonable but again it's a >> s/w policy not a h/w preference. Besides, I don't think we can include >> mmzone.h in pgtable.h. > > I think we can make a compromise: > 1. change the default implementation of arch_has_hw_pte_young() to return 0, and > 2. in memory.c, we can try PAGE_ALLOC_COSTLY_ORDER for archs that > don't override arch_has_hw_pte_young(), or if its return value is too > large to fit. > This should also take care of the regression, right? I think you are suggesting that we use 0 as a sentinel which we then translate to PAGE_ALLOC_COSTLY_ORDER? I already have a max_anon_folio_order() function in memory.c (actually it is currently a macro defined as arch_wants_pte_order()). So it would become (I'll talk about the vma concern separately in the thread where you raised it): static inline int max_anon_folio_order(struct vm_area_struct *vma) { int order = arch_wants_pte_order(vma); return order ? order : PAGE_ALLOC_COSTLY_ORDER; } Correct? I don't see how it fixes the regression (assume you're talking about Speedometer) though? On arm64 arch_wants_pte_order() will still be returning order-4. 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 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 3BF51C0015E for ; Thu, 6 Jul 2023 01:30:08 +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:In-Reply-To:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=cKiYT9EP3w2QRypTG85wWvzBQkjrQCSZzacGzjggJGk=; b=mIOF11W5l3h4ND NQYW0okaVlBsRbM4xMzKUemCA5NsXqhedKW73l5Y2KJtJowzq/Pdue7G5oPRcObxotnw0VHtZmQNl fH9j4vVDBP31QnHSZRsu/mwrlEYEMk+tKuzmf5M2QKM2/9g40+1o8h9B6Q9xLCyD5CdVWvOTBsCEm nEu0WHmmEV3UZ2FnY9AUu81gzM06iCYe6NOt5AFMZmvZcQRDhs9PxX1q7457Dngf9JgjaT2N5lOr8 7k8YIfzzpCjtOWDOvjMAFXAvzcPVrMpDTDN1XLqS4grXx/4PFAaqSCLLQOLDCAKF1FC+aj9Z1TdEp 8MMELZD+4zegyYyi/LoA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qHDoX-00HZSg-1T; Thu, 06 Jul 2023 01:29:45 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qHDoR-00HZOm-00 for linux-arm-kernel@lists.infradead.org; Thu, 06 Jul 2023 01:29:42 +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 1738F2F4; Tue, 4 Jul 2023 05:37:18 -0700 (PDT) Received: from [10.1.35.40] (C02Z41KALVDN.cambridge.arm.com [10.1.35.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0FC6E3F762; Tue, 4 Jul 2023 05:36:33 -0700 (PDT) Message-ID: <6d389825-1fc0-5c16-7858-2290fd632682@arm.com> Date: Tue, 4 Jul 2023 13:36:32 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [PATCH v2 3/5] mm: Default implementation of arch_wants_pte_order() To: Yu Zhao , "Yin, Fengwei" Cc: Andrew Morton , Matthew Wilcox , "Kirill A. Shutemov" , David Hildenbrand , Catalin Marinas , Will Deacon , Anshuman Khandual , Yang Shi , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20230703135330.1865927-1-ryan.roberts@arm.com> <20230703135330.1865927-4-ryan.roberts@arm.com> From: Ryan Roberts In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230705_182939_130435_A0D6EAF4 X-CRM114-Status: GOOD ( 24.03 ) 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: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org T24gMDQvMDcvMjAyMyAwNDo1OSwgWXUgWmhhbyB3cm90ZToKPiBPbiBNb24sIEp1bCAzLCAyMDIz 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