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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0AD17C2D0A8 for ; Wed, 23 Sep 2020 08:43:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D37B32220D for ; Wed, 23 Sep 2020 08:43:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726647AbgIWInV (ORCPT ); Wed, 23 Sep 2020 04:43:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:45882 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726130AbgIWInV (ORCPT ); Wed, 23 Sep 2020 04:43:21 -0400 Received: from gaia (unknown [31.124.44.166]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DF505221F0; Wed, 23 Sep 2020 08:43:19 +0000 (UTC) Date: Wed, 23 Sep 2020 09:43:17 +0100 From: Catalin Marinas To: Gavin Shan Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, mark.rutland@arm.com, anshuman.khandual@arm.com, robin.murphy@arm.com, will@kernel.org, shan.gavin@gmail.com Subject: Re: [PATCH v2 0/2] arm64/mm: Enable color zero pages Message-ID: <20200923084317.GA13434@gaia> References: <20200923053721.28873-1-gshan@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200923053721.28873-1-gshan@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Gavin, On Wed, Sep 23, 2020 at 03:37:19PM +1000, Gavin Shan wrote: > The feature of color zero pages isn't enabled on arm64, meaning all > read-only (anonymous) VM areas are backed up by same zero page. It > leads pressure to L1 (data) cache on reading data from them. This > tries to enable color zero pages. > > PATCH[1/2] decouples the zero PGD table from zero page > PATCH[2/2] allocates the needed zero pages according to L1 cache size To save you (and potential reviewers) some time, please include in the cover letter details of a realistic workload/benchmark that is improved by this patchset, backed by numbers. Just because it's doable and the patches aren't too complex is not a good enough reason for merging. Thanks. -- Catalin