Received: by 2002:ac0:a5a6:0:0:0:0:0 with SMTP id m35-v6csp472708imm; Thu, 30 Aug 2018 03:40:28 -0700 (PDT) X-Google-Smtp-Source: ANB0VdZoTu2RQWR8qHpIcV5AbMgkr9mInjuYvuNhBs/jyTC1Bthf+ewbs2Z507QI9laARoukUwX8 X-Received: by 2002:a62:1089:: with SMTP id 9-v6mr9933449pfq.30.1535625628790; Thu, 30 Aug 2018 03:40:28 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1535625628; cv=none; d=google.com; s=arc-20160816; b=BYX5Rx53ZPa4ubbRS2ps13YVQX55X9B8UGPNVzmVKFjOxpBXmVkIQ/DivlwAeOUYUi /Lra8h9om/QdpXrbWmaFbVcQd6sGkvgdFTB+HxhJtfTmrExaDZwIy2aaqTRN4QYd3Xk6 sEHpH96svH7b3/4+/AqWAfSWoUozzkAgbsk38iy+Ty3b1TBtYX31pHk1CaCiY9cEOk2X /T87GMT4baZR6C3PEA1K17GX7aO3hMxTucsBzFGx+2iceOWGBSgSmwc8laCyeO6zE69c zTHzE9tuzWGEA4N5rPHXXgV+uW8UYrh5egRMVPG9qqTAo8+WT8ft2k7R4jZBwCWvx69o qknA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date:dkim-signature:arc-authentication-results; bh=7vglJ+NZ4ZmZvWkw+w6q7eF3N8xslbTy/DARKonGKgo=; b=fzOPLOlCJieJJVAT4UOgwxMzKV0C2GwLKH/QGU4Gkf8B8mK4OfR/RE8x7yObyzbsoD DBLJNkJFXxEvlm0WrEdfkR84PyQu1bdvxLuWnv6apYaE95mzE9MOiftqvVur6gnnGfc4 zLxoaNfbJBdsTCnmJiXoUGASbZzBgTaHN8pFBJqB0FJa5hVD0QLlPr1gON1QFo01sXt8 L893Wnzo2qdKHb/VgrIuGRo/FOqDWhlR7mBoM1aVIiu9PhlbAynqdn7cEIVFNmK2BL7a JrN3DWnjJpyB41capor8Png3RmXjdTDRDaGLSbYq0Byvg87jja7ZFg8Z4tdHqqrPnIbC kvTA== ARC-Authentication-Results: i=1; mx.google.com; dkim=fail header.i=@infradead.org header.s=merlin.20170209 header.b=K851uWF5; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id c17-v6si6283355pge.273.2018.08.30.03.40.13; Thu, 30 Aug 2018 03:40:28 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=fail header.i=@infradead.org header.s=merlin.20170209 header.b=K851uWF5; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728432AbeH3Oki (ORCPT + 99 others); Thu, 30 Aug 2018 10:40:38 -0400 Received: from merlin.infradead.org ([205.233.59.134]:33348 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728311AbeH3Okh (ORCPT ); Thu, 30 Aug 2018 10:40:37 -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=7vglJ+NZ4ZmZvWkw+w6q7eF3N8xslbTy/DARKonGKgo=; b=K851uWF5RgWAbj/vPmWA8yYRS MLqzj+iDYTxLYKegi6vyUn74FiNbsLvUp1V58+icaBCCokHTf3jq33o4o22/ubezCPksTu9CLJE/h zFeb+PEpM0DJd25TLKqc+mc82+1zOoPy3ZnyVlrwenR4GSTH4A0cNdwe0lkR6U8m9lOMaiUWPrQux ws9jQuj9lEgABcrxQx7/Lad4pDoHqtbifqZWI3xbbUMTHqY0+XIRs7aVGkZkLJlD0iicMm1tcic8w siCZWE0A3vIPBNS9nltbLKz1BQQVkUjzRrRTtZbzM1crqYP30BVzBGv9TTEtZfjIZMkN7wdB0EUh2 WT2yyAv5w==; 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 1fvKLx-00085r-RK; Thu, 30 Aug 2018 10:39:06 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 877042024EB08; Thu, 30 Aug 2018 12:39:04 +0200 (CEST) Date: Thu, 30 Aug 2018 12:39:04 +0200 From: Peter Zijlstra To: Rich Felker Cc: Thomas Gleixner , linux-kernel@vger.kernel.org Subject: Re: futex_cmpxchg_enabled breakage Message-ID: <20180830103904.GA24160@hirez.programming.kicks-ass.net> References: <20180829222221.GA22017@brightrain.aerifal.cx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180829222221.GA22017@brightrain.aerifal.cx> 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, Aug 29, 2018 at 06:22:21PM -0400, Rich Felker wrote: > If there are archs that support SMP but don't provide their own Then throw it out the window and drive over it with a tank. Seriously, an SMP architecture that doesn't have native cmpxchg (or equivalent) is not worth anybodies time.