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=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, 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 DB105C5CFE7 for ; Wed, 11 Jul 2018 17:01:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 903E420C0C for ; Wed, 11 Jul 2018 17:01:17 +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="aMMBqbFF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 903E420C0C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388648AbeGKRG2 (ORCPT ); Wed, 11 Jul 2018 13:06:28 -0400 Received: from merlin.infradead.org ([205.233.59.134]:55548 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726460AbeGKRG2 (ORCPT ); Wed, 11 Jul 2018 13:06:28 -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=u3ddxNs9NdvaDqomWC07aM/o1rUlf2A9SwOsqRd5acI=; b=aMMBqbFFjzRw3UPwzIsayYlxV 68CCeZQaIPqLebyXIjX9kKRgB5jFjEvpp4/vUDnDeDzhchrbrKPL6GGB/r7mnNb8B/1Qce364JSZm j3Ou34wIB4X/x32m5zgfA5gqGk6EPQfJWDcu2DoZEqlg/JkMeDP6xB8LghpNHH83M6V8kJ3T/FJsW 3oBoX1VdP8+GjEo4yy6yTbfCb6aI2sOj6ldbzx3fX92ZRqwe9YFelrZ8mFsCr341QylUQqrFP6oOv Dd2P30DpgcGci7UeR8DrYoJIDEm5EVmzmSJDmElnw9ShLSz0x+Slhyt4siR9cut5bI0Ssnem58Djv riUBPRiTw==; 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 1fdIU3-0004xT-MO; Wed, 11 Jul 2018 17:00:55 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 2B6EA20289CB4; Wed, 11 Jul 2018 19:00:53 +0200 (CEST) Date: Wed, 11 Jul 2018 19:00:53 +0200 From: Peter Zijlstra To: Will Deacon Cc: Andrea Parri , Alan Stern , "Paul E. McKenney" , LKMM Maintainers -- Akira Yokosawa , Boqun Feng , Daniel Lustig , David Howells , Jade Alglave , Luc Maranget , Nicholas Piggin , Kernel development list Subject: Re: [PATCH v2] tools/memory-model: Add extra ordering for locks and remove it for ordinary release/acquire Message-ID: <20180711170053.GM2476@hirez.programming.kicks-ass.net> References: <20180710093821.GA5414@andrea> <20180711094310.GA13963@arm.com> <20180711123421.GA9673@andrea> <20180711155751.GC18477@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180711155751.GC18477@arm.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 11, 2018 at 04:57:51PM +0100, Will Deacon wrote: > It might be simple to model, but I worry this weakens our locking > implementations to a point where they will not be understood by the average > kernel developer. As I've said before, I would prefer "full" RCsc locking, Another vote for RCsc locks. The (in)famous hold-out is of course PowerPC, but it now looks like RISC-V is following where they I really rather wish they didn't.