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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0C125CCD193 for ; Thu, 23 Oct 2025 06:16:06 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2BDE78E0007; Thu, 23 Oct 2025 02:16:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 295868E0002; Thu, 23 Oct 2025 02:16:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1AB238E0007; Thu, 23 Oct 2025 02:16:06 -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 0607D8E0002 for ; Thu, 23 Oct 2025 02:16:06 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 8F577BC9C0 for ; Thu, 23 Oct 2025 06:16:05 +0000 (UTC) X-FDA: 84028368690.10.65C78A3 Received: from out30-111.freemail.mail.aliyun.com (out30-111.freemail.mail.aliyun.com [115.124.30.111]) by imf22.hostedemail.com (Postfix) with ESMTP id 396AEC0010 for ; Thu, 23 Oct 2025 06:16:01 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=linux.alibaba.com header.s=default header.b=Oz7tDJwM; dmarc=pass (policy=none) header.from=linux.alibaba.com; spf=pass (imf22.hostedemail.com: domain of ying.huang@linux.alibaba.com designates 115.124.30.111 as permitted sender) smtp.mailfrom=ying.huang@linux.alibaba.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1761200163; a=rsa-sha256; cv=none; b=0pNLp4DZjDh/MpGj0DOAVuWJjOXu3xNMfodnH+EsUeGQQi/ScR34csFLSgti+VJlwxXO0t q9WDrm3uJuYjB0uXMjVZe5l+NQLqBFVomlTy/Sq1NiDN5R1yqbRj0WacA8jK79mMGj1Ln6 2uWNlGUDC7gQksGw9IzVNUIsm/5LMcw= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=linux.alibaba.com header.s=default header.b=Oz7tDJwM; dmarc=pass (policy=none) header.from=linux.alibaba.com; spf=pass (imf22.hostedemail.com: domain of ying.huang@linux.alibaba.com designates 115.124.30.111 as permitted sender) smtp.mailfrom=ying.huang@linux.alibaba.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1761200163; 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:dkim-signature; bh=hhj1VLtSYO+AfqlDWQL1li1LYgXwZ69chK1m/bx772o=; b=cQSo8TSjSM/uKUzA7+Vmq0pXAFQEiPyShVboa8pBO2RJABJT4keUu33sSc96kVbfiWNXMA HvsXfMoGNxHRSe2J9UN9VuWFuXiYE//eTJrQFOEACnUlBUG3y88eGxgZSkINJR54uTc7Od ABIkcPVceetmQ8l2fX7wGFE2sGCY30M= DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1761200157; h=From:To:Subject:Date:Message-ID:MIME-Version:Content-Type; bh=hhj1VLtSYO+AfqlDWQL1li1LYgXwZ69chK1m/bx772o=; b=Oz7tDJwMASc/sBnzb8tuijEStdyfAngNV7W0jgMMEw5yZHgP4K8C2bo2rZXy3Pae18TIesBs/egYEa3HTkIleGO+WwTE0UV3w/QgDxvMneRVMNfABZjvRdePww0M2hw+odYE7Eq4hAUk8rvKYhPwK6ZcdiJWeUILpFm519+PKeM= Received: from DESKTOP-5N7EMDA(mailfrom:ying.huang@linux.alibaba.com fp:SMTPD_---0Wqq5ZkD_1761200155 cluster:ay36) by smtp.aliyun-inc.com; Thu, 23 Oct 2025 14:15:56 +0800 From: "Huang, Ying" To: Barry Song <21cnbao@gmail.com> Cc: Catalin Marinas , Will Deacon , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , Vlastimil Babka , Zi Yan , Baolin Wang , Ryan Roberts , Yang Shi , "Christoph Lameter (Ampere)" , Dev Jain , Anshuman Khandual , Yicong Yang , Kefeng Wang , Kevin Brodsky , Yin Fengwei , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH -v2 2/2] arm64, tlbflush: don't TLBI broadcast if page reused in write fault In-Reply-To: (Barry Song's message of "Thu, 23 Oct 2025 18:39:39 +1300") References: <20251013092038.6963-1-ying.huang@linux.alibaba.com> <20251013092038.6963-3-ying.huang@linux.alibaba.com> <87a51jfl44.fsf@DESKTOP-5N7EMDA> <871pmv9unr.fsf@DESKTOP-5N7EMDA> <875xc78es0.fsf@DESKTOP-5N7EMDA> <87a51j6zg7.fsf@DESKTOP-5N7EMDA> <87ms5j4444.fsf@DESKTOP-5N7EMDA> <87qzuu1kg2.fsf@DESKTOP-5N7EMDA> Date: Thu, 23 Oct 2025 14:15:53 +0800 Message-ID: <874irqywh2.fsf@DESKTOP-5N7EMDA> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Stat-Signature: kxc97oq9zorbfasiqanpmetmfbepdqhf X-Rspamd-Queue-Id: 396AEC0010 X-Rspamd-Server: rspam06 X-Rspam-User: X-HE-Tag: 1761200161-34180 X-HE-Meta: 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 ibmb7Pas I4RHbRvwIn0rCCFi0/NNhcl0OB1JVT06XryhQGYPopjKgKH83H/pxNrun55r8if9G0gLpeYUtjcHEKG3xxwy1I7pq0lPK66zcM9vXvSMYAsffPyXfdwkaqIbVNTBglTXvm9S33Ikm14gIPNn8RUT6K0yr/BF/7M8B6eC1ZdzoR+yDahfG8D9eFL16G38Ihybt1gJ/eyftTry1VKc5b/5Mr9C2VERRMyaa0T+8rL2y+YSrOD37kWcMXTkpscTDWwfHD/04VYkOOqj1hMETioOzoMNPcYhC81S5PeHn9SM669miIfc= 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: Barry Song <21cnbao@gmail.com> writes: >> > >> > A: >> > write pte >> > don't broadcast pte >> > tlbi >> > don't broadcast tlbi >> > >> > with >> > >> > B: >> > write pte >> > broadcast pte >> >> I suspect that pte will be broadcast, DVM broadcast isn't used for >> the memory coherency IIUC. > > I guess you=E2=80=99re right. By =E2=80=9Cbroadcast,=E2=80=9D I actually = meant the PTE becoming visible > to other CPUs. With a dsb(ish) before tlbi, other cores=E2=80=99 TLBs can= load the new > PTE after their TLB is shoot down. But as you said, if the hardware doesn= =E2=80=99t > propagate the updated PTE faster, it doesn=E2=80=99t seem to help reduce = page faults. > > As a side note, I=E2=80=99m curious about the data between dsb(nsh) and d= sb(ish) on > your platform. Perhaps because the number of CPU cores is small, I didn= =E2=80=99t see > any noticeable difference between them on phones. Sure. I can git it a try. Can you share the test case? >> >> > tlbi >> > don't broadcast tlbi >> > >> > I guess the gain comes from "don't broadcat tlbi" ? >> > With B, we should be able to share many existing code. >> >> Ryan has some plan to reduce the code duplication with the current >> solution. > > Ok. --- Best Regards, Huang, Ying