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_HELO_NONE,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 7CBEDC04AB5 for ; Thu, 6 Jun 2019 15:33:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A5EF20684 for ; Thu, 6 Jun 2019 15:33:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729441AbfFFPdC (ORCPT ); Thu, 6 Jun 2019 11:33:02 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46566 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729306AbfFFPdB (ORCPT ); Thu, 6 Jun 2019 11:33:01 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D950C550BB; Thu, 6 Jun 2019 15:32:54 +0000 (UTC) Received: from llong.remote.csb (dhcp-17-85.bos.redhat.com [10.18.17.85]) by smtp.corp.redhat.com (Postfix) with ESMTP id B88DC7D901; Thu, 6 Jun 2019 15:32:46 +0000 (UTC) Subject: Re: [PATCH v2 3/5] locking/qspinlock: Introduce CNA into the slow path of qspinlock To: Alex Kogan , Peter Zijlstra Cc: linux@armlinux.org.uk, mingo@redhat.com, will.deacon@arm.com, arnd@arndb.de, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Thomas Gleixner , bp@alien8.de, hpa@zytor.com, x86@kernel.org, Steven Sistare , Daniel Jordan , dave.dice@oracle.com, Rahul Yadav References: <20190329152006.110370-1-alex.kogan@oracle.com> <20190329152006.110370-4-alex.kogan@oracle.com> <60a3a2d8-d222-73aa-2df1-64c9d3fa3241@redhat.com> <20190402094320.GM11158@hirez.programming.kicks-ass.net> <6AEDE4F2-306A-4DF9-9307-9E3517C68A2B@oracle.com> <20190403160112.GK4038@hirez.programming.kicks-ass.net> <20190605204003.GC3402@hirez.programming.kicks-ass.net> <6426D627-77EE-471C-B02A-A85271B666E9@oracle.com> From: Waiman Long Organization: Red Hat Message-ID: <409b5d52-1f7d-7f60-04c7-e791e069239f@redhat.com> Date: Thu, 6 Jun 2019 11:32:46 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <6426D627-77EE-471C-B02A-A85271B666E9@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Thu, 06 Jun 2019 15:33:01 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/6/19 11:21 AM, Alex Kogan wrote: >>> Also, the paravirt code is under arch/x86, while CNA is generic (not >>> x86-specific). Do you still want to see CNA-related patching residing >>> under arch/x86? >>> >>> We still need a config option (something like NUMA_AWARE_SPINLOCKS) to >>> enable CNA patching under this config only, correct? >> There is the static_call() stuff that could be generic; I posted a new >> version of that today (x86 only for now, but IIRC there's arm64 patches >> for that around somewhere too). > The static_call technique appears as the more desirable long-term approach, but I think it would be prudent to keep the patches decoupled for now so we can move forward with less entanglements. > So unless anyone objects, we will work on plugging into the existing patching for pv. > And we will keep that code under arch/x86, but will be open for any suggestion to move it elsewhere. > If you mean making the CNV code depends on PARAVIRT_SPINLOCKS for now, that is fine. The code should be under kernel/locking. You shouldn't put it somewhere under arch/x86. -Longman