From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35242) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d0N6H-0001Yv-TW for qemu-devel@nongnu.org; Tue, 18 Apr 2017 02:58:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d0N6E-0003Cn-QC for qemu-devel@nongnu.org; Tue, 18 Apr 2017 02:58:58 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:3439 helo=dggrg02-dlp.huawei.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_ARCFOUR_SHA1:16) (Exim 4.71) (envelope-from ) id 1d0N6D-0003Bn-Pf for qemu-devel@nongnu.org; Tue, 18 Apr 2017 02:58:54 -0400 References: <1487734936-43472-1-git-send-email-zhang.zhanghailiang@huawei.com> <1487734936-43472-3-git-send-email-zhang.zhanghailiang@huawei.com> <134776c2-a85d-d06f-5f98-2e664f9c8ca9@cn.fujitsu.com> <58F06AA1.2010301@huawei.com> <9b42232a-e86f-2d61-7987-7a0559d6f705@redhat.com> <58F4A12C.5070404@huawei.com> From: Hailiang Zhang Message-ID: <58F5B902.8030105@huawei.com> Date: Tue, 18 Apr 2017 14:58:10 +0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH 02/15] colo-compare: implement the process of checkpoint List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jason Wang , Zhang Chen , qemu-devel@nongnu.org Cc: xuquan8@huawei.com, xiecl.fnst@cn.fujitsu.com, dgilbert@redhat.com, lizhijian@cn.fujitsu.com On 2017/4/18 11:55, Jason Wang wrote: > > On 2017年04月17日 19:04, Hailiang Zhang wrote: >> Hi Jason, >> >> On 2017/4/14 14:38, Jason Wang wrote: >>> On 2017年04月14日 14:22, Hailiang Zhang wrote: >>>> Hi Jason, >>>> >>>> On 2017/4/14 13:57, Jason Wang wrote: >>>>> On 2017年02月22日 17:31, Zhang Chen wrote: >>>>>> On 02/22/2017 11:42 AM, zhanghailiang wrote: >>>>>>> While do checkpoint, we need to flush all the unhandled packets, >>>>>>> By using the filter notifier mechanism, we can easily to notify >>>>>>> every compare object to do this process, which runs inside >>>>>>> of compare threads as a coroutine. >>>>>> Hi~ Jason and Hailiang. >>>>>> >>>>>> I will send a patch set later about colo-compare notify mechanism for >>>>>> Xen like this patch. >>>>>> I want to add a new chardev socket way in colo-comapre connect to Xen >>>>>> colo, for notify >>>>>> checkpoint or failover, Because We have no choice to use this way >>>>>> communicate with Xen codes. >>>>>> That's means we will have two notify mechanism. >>>>>> What do you think about this? >>>>>> >>>>>> >>>>>> Thanks >>>>>> Zhang Chen >>>>> I was thinking the possibility of using similar way to for colo >>>>> compare. >>>>> E.g can we use socket? This can saves duplicated codes more or less. >>>> Since there are too many sockets used by filter and COLO, (Two unix >>>> sockets and two >>>> tcp sockets for each vNIC), I don't want to introduce more ;) , but >>>> i'm not sure if it is >>>> possible to make it more flexible and optional, abstract these >>>> duplicated codes, >>>> pass the opened fd (No matter eventfd or socket fd ) as parameter, for >>>> example. >>>> Is this way acceptable ? >>>> >>>> Thanks, >>>> Hailiang >>> Yes, that's kind of what I want. We don't want to use two message >>> format. Passing a opened fd need management support, we still need a >>> fallback if there's no management on top. For qemu/kvm, we can do all >>> stuffs transparent to the cli by e.g socketpair() or others, but the key >>> is to have a unified message format. >> After a deeper investigation, i think we can re-use most codes, since >> there is no >> existing way to notify xen (no ?), we still needs notify chardev >> socket (Be used to notify xen, it is optional.) >> (http://patchwork.ozlabs.org/patch/733431/ "COLO-compare: Add Xen >> notify chardev socket handler frame") > Yes and actually you can use this for bi-directional communication. The > only differences is the implementation of comparing. > >> Besides, there is an existing qmp comand 'xen-colo-do-checkpoint', > I don't see this in master? Er, it has been merged already, please see migration/colo.c, void qmp_xen_colo_do_checkpoint(Error **errp); >> we can re-use it to notify >> colo-compare objects and other filter objects to do checkpoint, for >> the opposite direction, we use >> the notify chardev socket (Only for xen). > Just want to make sure I understand the design, who will trigger this > command? Management? The command will be issued by XEN (xc_save ?), the original existing xen-colo-do-checkpoint command now only be used to notify block replication to do checkpoint, we can re-use it for filters too. > Can we just use the socket? I don't quite understand ... Just as the codes showed bellow, in this scenario, XEN notifies colo-compare and fiters do checkpoint by using qmp command, and colo-compare notifies XEN about net inconsistency event by using the new socket. >> So the codes will be like: >> diff --git a/migration/colo.c b/migration/colo.c >> index 91da936..813c281 100644 >> --- a/migration/colo.c >> +++ b/migration/colo.c >> @@ -224,7 +224,19 @@ ReplicationStatus >> *qmp_query_xen_replication_status(Error **errp) >> >> void qmp_xen_colo_do_checkpoint(Error **errp) >> { >> + Error *local_err = NULL; >> + >> replication_do_checkpoint_all(errp); >> + /* Notify colo-compare and other filters to do checkpoint */ >> + colo_notify_compares_event(NULL, COLO_CHECKPOINT, &local_err); >> + if (local_err) { >> + error_propagate(errp, local_err); >> + return; >> + } >> + colo_notify_filters_event(COLO_CHECKPOINT, &local_err); >> + if (local_err) { >> + error_propagate(errp, local_err); >> + } >> } >> >> static void colo_send_message(QEMUFile *f, COLOMessage msg, >> diff --git a/net/colo-compare.c b/net/colo-compare.c >> index 24e13f0..de975c5 100644 >> --- a/net/colo-compare.c >> +++ b/net/colo-compare.c >> @@ -391,6 +391,9 @@ static void colo_compare_inconsistent_notify(void) >> { >> notifier_list_notify(&colo_compare_notifiers, >> migrate_get_current()); KVM will use this notifier/callback way, and in this way, we can avoid the redundant socket. >> + if (s->notify_dev) { >> + /* Do something, notify remote side through notify dev */ >> + } >> } If we have a notify socket configured, we will send the message about net inconsistent event. >> >> void colo_compare_register_notifier(Notifier *notify) >> >> How about this scenario ？ > See my reply above, and we need unify the message format too. Raw string > is ok but we'd better have something like TLV or others. Agreed, we need it to be more standard. Thanks, Hailiang > Thanks > >>> Thoughts? >>> >>> Thanks >>> >>>>> Thanks >>>>> >>>>> >>>>> . >>>>> >>> . >>> >> >> > > . >