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 E16C6C433EF for ; Wed, 2 Mar 2022 12:32:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6A4CC8D0003; Wed, 2 Mar 2022 07:32:03 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 652D18D0001; Wed, 2 Mar 2022 07:32:03 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 569A28D0003; Wed, 2 Mar 2022 07:32:03 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0212.hostedemail.com [216.40.44.212]) by kanga.kvack.org (Postfix) with ESMTP id 4660C8D0001 for ; Wed, 2 Mar 2022 07:32:03 -0500 (EST) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 0FE3182FC7 for ; Wed, 2 Mar 2022 12:32:03 +0000 (UTC) X-FDA: 79199383326.24.E08B4EB Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf13.hostedemail.com (Postfix) with ESMTP id 8298720009 for ; Wed, 2 Mar 2022 12:32:02 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A02FC61912; Wed, 2 Mar 2022 12:32:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 03B6FC340E9; Wed, 2 Mar 2022 12:31:57 +0000 (UTC) Date: Wed, 2 Mar 2022 12:31:54 +0000 From: Catalin Marinas To: Muchun Song Cc: will@kernel.org, akpm@linux-foundation.org, david@redhat.com, bodeddub@amazon.com, osalvador@suse.de, mike.kravetz@oracle.com, rientjes@google.com, mark.rutland@arm.com, james.morse@arm.com, song.bao.hua@hisilicon.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, duanxiongchun@bytedance.com, fam.zheng@bytedance.com, smuchun@gmail.com Subject: Re: [PATCH v2 RESEND 1/2] arm64: avoid flushing icache multiple times on contiguous HugeTLB Message-ID: References: <20220302084624.33340-1-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220302084624.33340-1-songmuchun@bytedance.com> X-Rspamd-Queue-Id: 8298720009 X-Stat-Signature: bb7t8ai665ohd4dxhuf54zq4adbej8yx X-Rspam-User: Authentication-Results: imf13.hostedemail.com; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none); spf=pass (imf13.hostedemail.com: domain of cmarinas@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=cmarinas@kernel.org X-Rspamd-Server: rspam03 X-HE-Tag: 1646224322-490059 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 Wed, Mar 02, 2022 at 04:46:23PM +0800, Muchun Song wrote: > When a contiguous HugeTLB page is mapped, set_pte_at() will be called > CONT_PTES/CONT_PMDS times. Therefore, __sync_icache_dcache() will > flush cache multiple times if the page is executable (to ensure > the I-D cache coherency). However, the first flushing cache already > covers subsequent cache flush operations. So only flusing cache > for the head page if it is a HugeTLB page to avoid redundant cache > flushing. In the next patch, it is also depends on this change > since the tail vmemmap pages of HugeTLB is mapped with read-only > meanning only head page struct can be modified. > > Signed-off-by: Muchun Song Reviewed-by: Catalin Marinas (for this patch only, I have yet to figure out whether Anshuman's and Mark's comments have been addressed in patch 2) -- Catalin