From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hal Rosenstock Subject: Re: [PATCH 0/7] Increase maximum Infiniband HCAs per-system Date: Mon, 1 Feb 2010 07:55:54 -0500 Message-ID: References: <20100129214039.17745.38679.stgit@bob.kio> <20100129234145.GC5177@ldl.fc.hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20100129234145.GC5177-e+Ta4ugHZmL3oGB3hsPCZA@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Alex Chiang Cc: Roland Dreier , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, justin.chen-VXdhtT5mjnY@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rdma@vger.kernel.org On Fri, Jan 29, 2010 at 6:41 PM, Alex Chiang wrote: > * Roland Dreier : >> >> Have you considered drivers/infiniband/core/user_mad.c and ucm.c? > > Ah, darn. I had not considered those drivers. You're gonna make > me learn a lot more about IB than I'd originally intended. ;) > >> I think user_mad.c is somewhat more important, as that is what >> allows an adapter to be used for running the SM. =C2=A0So I think >> we're still left with some potential issues around lots of >> adapters in one system. =C2=A0(I think use of ucm by real apps is >> minimal to nonexistent, but someday we should deal with that >> too) > > Ok, a quick glance through those drivers shows: > > =C2=A0 =C2=A0 =C2=A0 =C2=A0enum { > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0IB_UMAD_MAX_PO= RTS =C2=A0=3D 64, > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0IB_UMAD_MAX_AG= ENTS =3D 32, > > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0IB_UMAD_MAJOR = =C2=A0 =C2=A0 =C2=A0=3D 231, > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0IB_UMAD_MINOR_= BASE =3D 0 > =C2=A0 =C2=A0 =C2=A0 =C2=A0}; > > and > > =C2=A0 =C2=A0 =C2=A0 =C2=A0enum { > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0IB_UCM_MAJOR =3D= 231, > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0IB_UCM_BASE_MI= NOR =3D 224, > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0IB_UCM_MAX_DEV= ICES =3D 32 > =C2=A0 =C2=A0 =C2=A0 =C2=A0}; > > They're all sharing the same major number, so they'll all have to > get the same treatment as the uverbs driver wrt overflow (to > prevent minor number overlap). > > What I'm a little unsure of is, does IB_UMAD_MAX_AGENTS need to > double too? We don't export the agent id in the filesystem > anywhere, but we do give it to the user via an ioctl. That's just > used for book keeping purposes but... > > Currently, there are 2x as many ports as there are agents. Do we > want to keep that ratio, or would it be ok to have 4x as many > ports as there are agents? I think it's 2x as many ports as devices (based on the common HCAs being 2 ports max). This should be maintained as that is still the case. -- Hal > > Thanks (and sorry for the n00b questions). > > /ac > -- > 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 =C2=A0http://vger.kernel.org/majordomo-info.ht= ml > -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html