From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752587AbcB2KCQ (ORCPT <rfc822;w@1wt.eu>);
	Mon, 29 Feb 2016 05:02:16 -0500
Received: from bombadil.infradead.org ([198.137.202.9]:54464 "EHLO
	bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1751126AbcB2KCO (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Mon, 29 Feb 2016 05:02:14 -0500
Date: Mon, 29 Feb 2016 11:01:10 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Russell King <linux@arm.linux.org.uk>, Ingo Molnar <mingo@redhat.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-api <linux-api@vger.kernel.org>, Paul Turner <pjt@google.com>,
        Andrew Hunter <ahh@google.com>, Andy Lutomirski <luto@amacapital.net>,
        Andi Kleen <andi@firstfloor.org>, Dave Watson <davejwatson@fb.com>,
        Chris Lameter <cl@linux.com>, Ben Maurer <bmaurer@fb.com>,
        rostedt <rostedt@goodmis.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Josh Triplett <josh@joshtriplett.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Michael Kerrisk <mtk.manpages@gmail.com>
Subject: Re: [PATCH v4 1/5] getcpu_cache system call: cache CPU number of
 running thread
Message-ID: <20160229100110.GH6356@twins.programming.kicks-ass.net>
References: <alpine.DEB.2.11.1602261719440.3638@nanos>
 <967083634.8940.1456507201156.JavaMail.zimbra@efficios.com>
 <alpine.DEB.2.11.1602261855100.3638@nanos>
 <724964987.9217.1456518255392.JavaMail.zimbra@efficios.com>
 <7096DA23-3908-40DC-A46B-C4CF2252CEE8@zytor.com>
 <1150363257.9781.1456533630895.JavaMail.zimbra@efficios.com>
 <56D14132.5050100@zytor.com>
 <2053850250.10158.1456582501604.JavaMail.zimbra@efficios.com>
 <20160227145809.GD6356@twins.programming.kicks-ass.net>
 <CA+55aFysWipEagSdgeXbLx+Au4vomvyttdNFJtM+HffmBECQiA@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CA+55aFysWipEagSdgeXbLx+Au4vomvyttdNFJtM+HffmBECQiA@mail.gmail.com>
User-Agent: Mutt/1.5.21 (2012-12-30)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Sat, Feb 27, 2016 at 10:35:28AM -0800, Linus Torvalds wrote:
> On Sat, Feb 27, 2016 at 6:58 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > Paul's patches have the following structure:
> >
> > struct thread_local_abi {
> >         union {
> >                 struct {
> >                         u32     cpu_id;
> >                         u32     seq;
> >                 };
> >                 u64 cpu_seq;
> >         };
> >         unsigned long post_commit_ip;
> > };
> 
> Please don't do "unsigned long" in ABI structures any more.
> 
> Make it u64, and make sure it is 64-bit aligned (which it would be in
> this case). Make it so that we don't have to have separate compat
> paths.

Yes, for sure. I was 'only' trying to reflect the state of the last rseq
patches. But yes, I should have called that out and avoided 'confusion'.