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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 9831EC4360F for ; Thu, 4 Apr 2019 09:39:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D1C8205F4 for ; Thu, 4 Apr 2019 09:39:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ecz0z6kR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732057AbfDDJjS (ORCPT ); Thu, 4 Apr 2019 05:39:18 -0400 Received: from merlin.infradead.org ([205.233.59.134]:53550 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729287AbfDDJjQ (ORCPT ); Thu, 4 Apr 2019 05:39:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=RidMHjcG2n3Ka1GU8mcjqYcEO6QOzS8K6B8jmbrnzjM=; b=ecz0z6kR40bYeXQnEgfyDpmst xY0vGJfXamJKzNLe1he9e54Rkp1VEZLV/ekoxE++1vO2NcdiNfDhBh/Tn2Bkf3aYiMpSQSdCzE3br ni4iKI0K2gwBu7QqaztS2nN9lelc+0o44fpwWJdr9ut3uvnTJuuIfg90As1116uESzQ+euS3qLgd6 5LvjYHgmdWo4BYuI1QkR0kGkn+Y30Ixtow9woivM3ntTSO7Fy4uZMhTO+MYjaZxijAVCmo2RDVOqF X/wGWbha4BaS4Ee6mhTyivtx5Q2LqYiFYjImLqgQsiOMbbqP39r4NTn5B3eximGavnVYv4b+V6Nc8 2qq24y6sQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hBypq-0002Nt-00; Thu, 04 Apr 2019 09:39:02 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 721CC2038C23E; Thu, 4 Apr 2019 11:38:59 +0200 (CEST) Date: Thu, 4 Apr 2019 11:38:59 +0200 From: Peter Zijlstra To: Juergen Gross Cc: Alex Kogan , Waiman Long , 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, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, x86@kernel.org, steven.sistare@oracle.com, daniel.m.jordan@oracle.com, dave.dice@oracle.com, rahul.x.yadav@oracle.com Subject: Re: [PATCH v2 3/5] locking/qspinlock: Introduce CNA into the slow path of qspinlock Message-ID: <20190404093859.GU4038@hirez.programming.kicks-ass.net> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 04, 2019 at 07:05:24AM +0200, Juergen Gross wrote: > Without PARAVIRT_SPINLOCK this would be just an alternative() then? That could maybe work yes. This is all early enough. > Maybe the resulting code would be much more readable if we'd just > make PARAVIRT_SPINLOCK usable without the other PARAVIRT hooks? So > splitting up PARAVIRT into PARAVIRT_GUEST (timer hooks et al) and > the patching infrastructure, with PARAVIRT_GUEST and PARAVIRT_SPINLOCK > selecting PARAVIRT, and PARAVIRT_XXL selecting PARAVIRT_GUEST. Well, ideally we'll get static_call() sorted and use that.