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_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 02046C0044C for ; Thu, 1 Nov 2018 17:15:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A038A2064C for ; Thu, 1 Nov 2018 17:15:03 +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="gdTDPDZT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A038A2064C 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-nfs-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726232AbeKBCSx (ORCPT ); Thu, 1 Nov 2018 22:18:53 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:57006 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725843AbeKBCSx (ORCPT ); Thu, 1 Nov 2018 22:18:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=ma3LP1JT+d0hJ1ipGHv8/xbHP5Yk8y77+qZqZv7uYZ0=; b=gdTDPDZTLiwW6lM1tuILcZdvw qqVhAeWF4ynHujkSXNAEm/u7v6nK4ymMaziRzE5VoQilbCorYXURmXQXThpxN+5pzZJGmKAFeOYbV 2hkhje3QKPRjEozGs8wVDDesg5fzq3YFIxroaz3rpvmqOXq0izC3fW66p5U7s49Q3EfsoOy7q1cNe +fgoba1e0ElZACsL6oNJGyjYtkR70ojujtiT0RpOV3UhGXtMiO2FmeZwr+KLhJV7jBoBGqp+BxSkZ po3276nyM4q9EkqWYj72vF5FmU+E0W2bcNbN9C7BkL1+xjui2LPjpAqrw9onDSVX/SS/hmQX/qFw5 5jL0XRh2g==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gIGYE-0007Uw-ME; Thu, 01 Nov 2018 17:14:34 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 339352029F9FF; Thu, 1 Nov 2018 18:14:32 +0100 (CET) Date: Thu, 1 Nov 2018 18:14:32 +0100 From: Peter Zijlstra To: Eric Dumazet Cc: Trond Myklebust , "mark.rutland@arm.com" , "linux-kernel@vger.kernel.org" , "ralf@linux-mips.org" , "jlayton@kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "bfields@fieldses.org" , "linux-mips@linux-mips.org" , "linux@roeck-us.net" , "linux-nfs@vger.kernel.org" , "akpm@linux-foundation.org" , "will.deacon@arm.com" , "boqun.feng@gmail.com" , "paul.burton@mips.com" , "anna.schumaker@netapp.com" , "jhogan@kernel.org" , "netdev@vger.kernel.org" , "davem@davemloft.net" , "arnd@arndb.de" , "paulus@samba.org" , "mpe@ellerman.id.au" , "benh@kernel.crashing.org" , Paul McKenney , aryabinin@virtuozzo.com, dvyukov@google.com Subject: Re: [RFC PATCH] lib: Introduce generic __cmpxchg_u64() and use it where needed Message-ID: <20181101171432.GH3178@hirez.programming.kicks-ass.net> References: <1541015538-11382-1-git-send-email-linux@roeck-us.net> <20181031213240.zhh7dfcm47ucuyfl@pburton-laptop> <20181031220253.GA15505@roeck-us.net> <20181031233235.qbedw3pinxcuk7me@pburton-laptop> <4e2438a23d2edf03368950a72ec058d1d299c32e.camel@hammerspace.com> <20181101131846.biyilr2msonljmij@lakrids.cambridge.arm.com> <20181101145926.GE3178@hirez.programming.kicks-ass.net> <20181101163212.GF3159@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-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Thu, Nov 01, 2018 at 09:59:38AM -0700, Eric Dumazet wrote: > On 11/01/2018 09:32 AM, Peter Zijlstra wrote: > > >> Anyhow, if the atomic maintainers are willing to stand up and state for > >> the record that the atomic counters are guaranteed to wrap modulo 2^n > >> just like unsigned integers, then I'm happy to take Paul's patch. > > > > I myself am certainly relying on it. > > Could we get uatomic_t support maybe ? Whatever for; it'd be the exact identical same functions as for atomic_t, except for a giant amount of code duplication to deal with the new type. That is; today we merged a bunch of scripts that generates most of atomic*_t, so we could probably script uatomic*_t wrappers with minimal effort, but it would add several thousand lines of code to each compile for absolutely no reason what so ever. > This reminds me of this sooooo silly patch :/ > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=adb03115f4590baa280ddc440a8eff08a6be0cb7 Yes, that's stupid. UBSAN is just wrong there.