From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pradeep Satyanarayana Subject: Re: how to preserve QP over HA events for librdmacm applications Date: Thu, 20 Sep 2012 13:57:45 -0700 Message-ID: <505B8349.4050402@linux.vnet.ibm.com> References: <5059E82E.9020600@mellanox.com> <1828884A29C6694DAF28B7E6B8A8237346A8E418@ORSMSX101.amr.corp.intel.com> <5059EA48.1040407@mellanox.com> <46C75A5F-AD9F-45CF-A441-B7D5F60709D8@ornl.gov> <1828884A29C6694DAF28B7E6B8A8237346A8E47E@ORSMSX101.amr.corp.intel.com> <86756672-ADCC-4EF0-A24C-19C4A0EB8188@ornl.gov> <505B5470.9030707@linux.vnet.ibm.com> <1828884A29C6694DAF28B7E6B8A8237346A8E77F@ORSMSX101.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1828884A29C6694DAF28B7E6B8A8237346A8E77F-P5GAC/sN6hmkrb+BlOpmy7fspsVTdybXVpNB7YpNyf8@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Hefty, Sean" Cc: "Atchley, Scott" , Alex Rosenbaum , Or Gerlitz , "linux-rdma (linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org)" List-Id: linux-rdma@vger.kernel.org On 09/20/2012 01:10 PM, Hefty, Sean wrote: >> What if you say pre-created a second (fail over) QP for HA purposes all >> under the covers of a single socket? And both QPs were connected before >> the failure. Not sure if that would work with the same CM id though. If >> not, we will need to rdma_connect() the second QP after failure. > > CM IDs are not shared across devices, and can't be reused for different QPs until the first connection has been torn down and gone through timewait. For IB, you probably want path migration capabilities. > Fair enough, I understand one needs to use a different CM id. For the IB case I was thinking of avoiding APM (since that is limited to a device -isn't that so?). > Anything more generic should really be handled by the application. Migrating a connection between devices also requires using different CQs, PDs, MRs, etc. > Is PD device specific? Couldn't one reuse the same CQs and MRs, even though the QP is different? Of course only one QP would be active at any time. Thanks Pradeep -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html