From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41495) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ybt9f-0004gL-Uw for qemu-devel@nongnu.org; Sat, 28 Mar 2015 12:00:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ybt9Z-0004fR-Ql for qemu-devel@nongnu.org; Sat, 28 Mar 2015 12:00:11 -0400 Received: from mail-wg0-x232.google.com ([2a00:1450:400c:c00::232]:34837) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ybt9Z-0004db-L3 for qemu-devel@nongnu.org; Sat, 28 Mar 2015 12:00:05 -0400 Received: by wgdm6 with SMTP id m6so128494987wgd.2 for ; Sat, 28 Mar 2015 09:00:05 -0700 (PDT) Sender: Paolo Bonzini Message-ID: <5516D000.3010107@redhat.com> Date: Sat, 28 Mar 2015 17:00:00 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1424883128-9841-1-git-send-email-dgilbert@redhat.com> <1424883128-9841-18-git-send-email-dgilbert@redhat.com> <20150312093049.GW11973@voom.redhat.com> <20150326163327.GG2370@work-vm> <20150327041353.GD2900@voom.fritz.box> <20150327104851.GC2685@work-vm> In-Reply-To: <20150327104851.GC2685@work-vm> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v5 17/45] Add wrappers and handlers for sending/receiving the postcopy-ram migration messages. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" , David Gibson Cc: aarcange@redhat.com, yamahata@private.email.ne.jp, quintela@redhat.com, qemu-devel@nongnu.org, amit.shah@redhat.com, yanghy@cn.fujitsu.com On 27/03/2015 11:48, Dr. David Alan Gilbert wrote: > > So, I like the idea of one message per action in principle - but only > > if that action really is well-defined without reference to what > > operations come before and after it. If there are hidden dependencies > > about what actions have to come in what order, I'd rather bake that > > into the command structure. > > In no way is it hidden; the commands match the state transitions. So is there only one writer thread? In which states can the other threads read the postcopy state, and why is sequential consistency important? That is, in threads other than the writer, how does reading the state interact with other reads and writes? Paolo