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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 800E3C43381 for ; Tue, 19 Feb 2019 03:08:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4CC9E2064C for ; Tue, 19 Feb 2019 03:08:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726000AbfBSDIz (ORCPT ); Mon, 18 Feb 2019 22:08:55 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:39718 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725613AbfBSDIz (ORCPT ); Mon, 18 Feb 2019 22:08:55 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4CB1480D; Mon, 18 Feb 2019 19:08:54 -0800 (PST) Received: from [10.162.40.139] (p8cg001049571a15.blr.arm.com [10.162.40.139]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0EB4C3F575; Mon, 18 Feb 2019 19:08:50 -0800 (PST) Subject: Re: [PATCH] arm64: mm: enable per pmd page table lock To: Yu Zhao , Catalin Marinas , Will Deacon Cc: "Aneesh Kumar K . V" , Andrew Morton , Nick Piggin , Peter Zijlstra , Joel Fernandes , "Kirill A . Shutemov" , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org References: <20190214211642.2200-1-yuzhao@google.com> From: Anshuman Khandual Message-ID: Date: Tue, 19 Feb 2019 08:38:54 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190214211642.2200-1-yuzhao@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/15/2019 02:46 AM, Yu Zhao wrote: > Switch from per mm_struct to per pmd page table lock by enabling > ARCH_ENABLE_SPLIT_PMD_PTLOCK. This provides better granularity for > large system. > > I'm not sure if there is contention on mm->page_table_lock. Given > the option comes at no cost (apart from initializing more spin > locks), why not enable it now. > This has similar changes to what I had posted part of the general page table page accounting clean up series on arm64 last month. https://www.spinics.net/lists/arm-kernel/msg701954.html