From owner-svn-src-head@freebsd.org  Fri Jun  8 05:36:29 2018
Return-Path: <owner-svn-src-head@freebsd.org>
Delivered-To: svn-src-head@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 69BDB101106E;
 Fri,  8 Jun 2018 05:36:29 +0000 (UTC)
 (envelope-from kostikbel@gmail.com)
Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id D7FAE73E48;
 Fri,  8 Jun 2018 05:36:28 +0000 (UTC)
 (envelope-from kostikbel@gmail.com)
Received: from tom.home (kib@localhost [127.0.0.1])
 by kib.kiev.ua (8.15.2/8.15.2) with ESMTP id w585aDKA053768;
 Fri, 8 Jun 2018 08:36:16 +0300 (EEST)
 (envelope-from kostikbel@gmail.com)
DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua w585aDKA053768
Received: (from kostik@localhost)
 by tom.home (8.15.2/8.15.2/Submit) id w585aDkA053767;
 Fri, 8 Jun 2018 08:36:13 +0300 (EEST)
 (envelope-from kostikbel@gmail.com)
X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com
 using -f
Date: Fri, 8 Jun 2018 08:36:13 +0300
From: Konstantin Belousov <kostikbel@gmail.com>
To: Mateusz Guzik <mjguzik@gmail.com>
Cc: Ryan Libby <rlibby@freebsd.org>, Mark Johnston <markj@freebsd.org>,
 Justin Hibbits <jhibbits@freebsd.org>,
 src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: Re: svn commit: r334708 - head/sys/kern
Message-ID: <20180608053613.GI2450@kib.kiev.ua>
References: <201806061257.w56CvCwq089369@repo.freebsd.org>
 <20180606140311.GU2450@kib.kiev.ua> <20180608033242.GA54099@pesky>
 <CAHgpiFyOQf6B3oGFGMz3avXqrrP0i6Puy9HqLER1XG5xE67BeQ@mail.gmail.com>
 <CAGudoHENGpCxn_omxfaRLOAH5fP6qdFcmmqZ7He+pcC=-1HFKQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAGudoHENGpCxn_omxfaRLOAH5fP6qdFcmmqZ7He+pcC=-1HFKQ@mail.gmail.com>
User-Agent: Mutt/1.10.0 (2018-05-17)
X-Spam-Status: No, score=-2.0 required=5.0 tests=ALL_TRUSTED,BAYES_00,
 DKIM_ADSP_CUSTOM_MED,FREEMAIL_FROM,NML_ADSP_CUSTOM_MED autolearn=no
 autolearn_force=no version=3.4.1
X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on tom.home
X-BeenThere: svn-src-head@freebsd.org
X-Mailman-Version: 2.1.26
Precedence: list
List-Id: SVN commit messages for the src tree for head/-current
 <svn-src-head.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-head/>
List-Post: <mailto:svn-src-head@freebsd.org>
List-Help: <mailto:svn-src-head-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 08 Jun 2018 05:36:29 -0000

On Fri, Jun 08, 2018 at 07:03:04AM +0200, Mateusz Guzik wrote:
> Part of the problem is lack of primitives like READ_ONCE/WRITE_ONCE as
> seen in the linux kernel, someone should hack up equivalents.
Only replying to this statement right now.  What is the semantic of
the _ONCE operations ?  Isn't it the same as atomic_load/store (without
fences) ?