From mboxrd@z Thu Jan 1 00:00:00 1970 From: srinivas eeda Date: Wed, 17 Feb 2010 16:59:33 -0800 Subject: [Ocfs2-devel] [PATCH 3/3] o2net: correct keepalive message protocol In-Reply-To: <4B7C80C1.4060400@oracle.com> References: <1264740671-908-1-git-send-email-srinivas.eeda@oracle.com> <1264740671-908-4-git-send-email-srinivas.eeda@oracle.com> <20100217055641.GI13798@mail.oracle.com> <4B7C345E.6000504@oracle.com> <4B7C706F.7060807@oracle.com> <4B7C732A.8000204@oracle.com> <4B7C720E.3060401@oracle.com> <4B7C7F94.206@oracle.com> <4B7C80C1.4060400@oracle.com> Message-ID: <4B7C90F5.5000909@oracle.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com Ok, I'll modify the patch. Are messages queued on o2net_wq and execution of o2net_process_message is always done in the context of o2net thread and are synchronized? On 2/17/2010 3:50 PM, Sunil Mushran wrote: > My understanding was that we'll also requeue after sending a keepalive. > As in, not wait for the response to requeue. But we'll still be smart > about > it in the sense that not send a hb even if the nodes are communicating > otherwise. > > Srinivas Eeda wrote: >> In old code a node cancels and re queues keep alive message when it >> hears from the other node. If it didn't hear in 2 seconds, queued >> message gets fired which sends a keep alive message. And a re queue >> happens only after it hears from the other node. >> >> With the new change, a node sends keep alive every 2 seconds. >> >> Sunil Mushran wrote: >>> How will it double? The node will send a keepalive only if it has >>> not heard from the other node for 2 secs. >>> >>> Srinivas Eeda wrote: >>>> No harm, just doubles heartbeat messages which is not required at all. >>>> >>>> Sunil Mushran wrote: >>>>> What's the harm in leaving it in? >>>>> >>>>> Srinivas Eeda wrote: >>>>>> Each node that has this patch would send a >>>>>> O2NET_MSG_KEEP_REQ_MAGIC every 2 seconds(default). So, nodes >>>>>> without this patch would always receive a heartbeat message every >>>>>> 2 seconds. >>>>>> >>>>>> Nodes without this patch will send(respond) with >>>>>> O2NET_MSG_KEEP_RESP_MAGIC for every keep alive packet they >>>>>> received. So nodes with this patch will always receive a response >>>>>> message. >>>>>> >>>>>> So, in a mixed setup, both nodes will always hear the heartbeat >>>>>> from each other :). >>>>>> >>>>>> thanks, >>>>>> --Srini >>>>>> >>>>>> >>>>>> >>>>>> Joel Becker wrote: >>>>>> >>>>>>> On Thu, Jan 28, 2010 at 08:51:11PM -0800, Srinivas Eeda wrote: >>>>>>> >>>>>>>> case O2NET_MSG_KEEP_REQ_MAGIC: >>>>>>>> - o2net_sendpage(sc, o2net_keep_resp, >>>>>>>> - sizeof(*o2net_keep_resp)); >>>>>>>> + /* Each node now sends keepalive message every >>>>>>>> + * keepalive time interval. Hence no need for >>>>>>>> response >>>>>>>> + */ >>>>>>>> goto out; >>>>>>>> >>>>>>> You still have to send the response. Think about a mixed >>>>>>> environment where some nodes have this fix and some do not. The >>>>>>> older >>>>>>> software is still waiting on the response. >>>>>>> The newer version can just ignore any responses it gets from >>>>>>> other nodes. But it has to send responses out just in case the >>>>>>> other >>>>>>> node is older. >>>>>>> The only other alternative is to bump the o2net protocol >>>>>>> version, and that means the cluster has to be shut down to >>>>>>> upgrade. Not >>>>>>> a good choice. >>>>>>> >>>>>>> Joel >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> Ocfs2-devel mailing list >>>>>> Ocfs2-devel at oss.oracle.com >>>>>> http://oss.oracle.com/mailman/listinfo/ocfs2-devel >>>>>> >>>>> >>>> >>> >> >