From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52921) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XrmuZ-0001Mt-Mq for qemu-devel@nongnu.org; Fri, 21 Nov 2014 07:02:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XrmuQ-0004Io-MZ for qemu-devel@nongnu.org; Fri, 21 Nov 2014 07:02:03 -0500 Received: from mail-wi0-x235.google.com ([2a00:1450:400c:c05::235]:42396) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XrmuQ-0004Ii-FY for qemu-devel@nongnu.org; Fri, 21 Nov 2014 07:01:54 -0500 Received: by mail-wi0-f181.google.com with SMTP id r20so8585299wiv.2 for ; Fri, 21 Nov 2014 04:01:52 -0800 (PST) Sender: Paolo Bonzini Message-ID: <546F29A9.5030501@redhat.com> Date: Fri, 21 Nov 2014 13:01:45 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1412358473-31398-1-git-send-email-dgilbert@redhat.com> <1412358473-31398-34-git-send-email-dgilbert@redhat.com> <54301FEE.10403@redhat.com> <20141120114502.GE5983@work-vm> In-Reply-To: <20141120114502.GE5983@work-vm> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v4 33/47] Postcopy: Postcopy startup in migration thread List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: aarcange@redhat.com, yamahata@private.email.ne.jp, quintela@redhat.com, cristian.klein@cs.umu.se, qemu-devel@nongnu.org, amit.shah@redhat.com, yanghy@cn.fujitsu.com On 20/11/2014 12:45, Dr. David Alan Gilbert wrote: > > For this case QEMU has atomic_read/atomic_set (corresponding to > > __ATOMIC_RELAXED in C/C++1x), so you could use those as well. > > Ah, so those look like they just volatile cast anyway. Yeah, but it explicitly shows that the assignment is a) for a multi-threaded operation b) using relaxed semantics. It attaches the information to the use instead of the variable; it just happens that volatile is the pre-C11 way to express those. Paolo