From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Weiny, Ira" Subject: RE: [PATCH v4 14/19] IB/core: Add IB_DEVICE_OPA_MAD_SUPPORT device cap flag Date: Wed, 11 Feb 2015 15:40:39 +0000 Message-ID: <2807E5FD2F6FDA4886F6618EAC48510E0CC244A8@CRSMSX101.amr.corp.intel.com> References: <1423092585-26692-1-git-send-email-ira.weiny@intel.com> <1423092585-26692-15-git-send-email-ira.weiny@intel.com> <54D52589.8020305@dev.mellanox.co.il> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <54D52589.8020305-LDSdmyG8hGV8YrgS2mwiifqBs+8SCbDb@public.gmane.org> Content-Language: en-US Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: 'Hal Rosenstock' Cc: "roland-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org" , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-rdma@vger.kernel.org > On 2/4/2015 6:29 PM, ira.weiny-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org wrote: > > From: Ira Weiny > > > > OPA MADs share a common header with IBTA MADs but with a different > > base version and an extended length. These "jumbo" MADs increase the > > performance of management traffic. > > > > Sharing a common header with IBTA MADs allows us to share most of the > > MAD processing code when dealing with OPA MADs in addition to > > supporting some IBTA MADs on OPA devices. > > > > Add a device capability flag to indicate OPA MAD support on the device. > > > > Signed-off-by: Ira Weiny > > > > --- > > include/rdma/ib_verbs.h | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h index > > 3ab4033..2614233 100644 > > --- a/include/rdma/ib_verbs.h > > +++ b/include/rdma/ib_verbs.h > > @@ -128,6 +128,10 @@ enum ib_device_cap_flags { > > IB_DEVICE_ON_DEMAND_PAGING = (1<<31), > > }; > > > > +enum ib_device_cap_flags2 { > > + IB_DEVICE_OPA_MAD_SUPPORT = 1 > > +}; > > + > > enum ib_signature_prot_cap { > > IB_PROT_T10DIF_TYPE_1 = 1, > > IB_PROT_T10DIF_TYPE_2 = 1 << 1, > > @@ -210,6 +214,7 @@ struct ib_device_attr { > > int sig_prot_cap; > > int sig_guard_cap; > > struct ib_odp_caps odp_caps; > > + u64 device_cap_flags2; > > u32 max_mad_size; > > }; > > > > Why is OPA support determined via a device capability flag ? What are the > tradeoffs for doing it this way versus the other choices that have been used in > the past for other RDMA technologies like RoCE, iWARP, usNIC, ... ? None of those technologies use the MAD stack for Subnet Management. Other MAD support is very limited (ie IB compatible PMA queries on the local port only). Do you have a suggestion for alternatives? Ira -- 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