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 9B5AFC46CA2 for ; Tue, 19 Dec 2023 08:18:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 37B578D000F; Tue, 19 Dec 2023 03:18:27 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 32A998D0005; Tue, 19 Dec 2023 03:18:27 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1F2668D000F; Tue, 19 Dec 2023 03:18:27 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 0F2D98D0005 for ; Tue, 19 Dec 2023 03:18:27 -0500 (EST) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id D9C7414022C for ; 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imf10.hostedemail.com; dkim=none; spf=pass (imf10.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-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1702973904; a=rsa-sha256; cv=none; b=7/hfBgBXP1g31QWoYhKO6SuirkLK9PuM1umLXeouQjr9yz4ljfuHKFLEhYJwe6zqaJQ1OB rtPfSQ+XrEyPeyUjC/wafSnlKTXoQ8hw2tLwZcE93dr7wONB7X9cQ4Ls6daqiWtRTr2uao 9lPMbBlRfJY/S83HgG8WTWzMBr7jO/4= 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 45EB31FB; Tue, 19 Dec 2023 00:19:07 -0800 (PST) Received: from [10.57.75.230] (unknown [10.57.75.230]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E3D2F3F738; Tue, 19 Dec 2023 00:18:18 -0800 (PST) Message-ID: Date: Tue, 19 Dec 2023 08:18:17 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 01/16] mm: thp: Batch-collapse PMD with set_ptes() Content-Language: en-GB To: David Hildenbrand , Catalin Marinas , Will Deacon , Ard Biesheuvel , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Zenghui Yu , Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , Andrew Morton , Anshuman Khandual , Matthew Wilcox , Yu Zhao , Mark Rutland , Kefeng Wang , John Hubbard , Zi Yan , Barry Song <21cnbao@gmail.com>, Alistair Popple , Yang Shi Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20231218105100.172635-1-ryan.roberts@arm.com> <20231218105100.172635-2-ryan.roberts@arm.com> <8ce9f79c-be2f-4fa2-b356-39436a1d108a@redhat.com> From: Ryan Roberts In-Reply-To: <8ce9f79c-be2f-4fa2-b356-39436a1d108a@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 52C1BC001A X-Rspam-User: X-Stat-Signature: d9n6rfax66c4fwuaxf9o3ssspmwkxuoh X-Rspamd-Server: rspam01 X-HE-Tag: 1702973904-854521 X-HE-Meta: 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 F5Q== 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: List-Subscribe: List-Unsubscribe: On 18/12/2023 17:40, David Hildenbrand wrote: > On 18.12.23 11:50, Ryan Roberts wrote: >> Refactor __split_huge_pmd_locked() so that a present PMD can be >> collapsed to PTEs in a single batch using set_ptes(). It also provides a >> future opportunity to batch-add the folio to the rmap using David's new >> batched rmap APIs. > > I'd drop that sentence and rather just say "In the future, we might get rid of > the remaining manual loop by using rmap batching.". OK fair enough. Will fix for next version. > >> >> This should improve performance a little bit, but the real motivation is >> to remove the need for the arm64 backend to have to fold the contpte >> entries. Instead, since the ptes are set as a batch, the contpte blocks >> can be initially set up pre-folded (once the arm64 contpte support is >> added in the next few patches). This leads to noticeable performance >> improvement during split. >> > Acked-by: David Hildenbrand Thanks!