From: Andrew Morton <akpm@osdl.org>
To: Caitlin Bestler <caitlin.bestler@gmail.com>
Cc: libor@topspin.com, hch@infradead.org,
linux-kernel@vger.kernel.org, openib-general@openib.org,
timur.tabi@ammasso.com
Subject: Re: [openib-general] Re: [PATCH][RFC][0/4] InfiniBand userspace verbs implementation
Date: Mon, 25 Apr 2005 17:10:50 -0700 [thread overview]
Message-ID: <20050425171050.5ba25918.akpm@osdl.org> (raw)
In-Reply-To: <469958e00504251637350cc8c@mail.gmail.com>
Caitlin Bestler <caitlin.bestler@gmail.com> wrote:
>
> >
> > > > This is because there is no file descriptor or anything else associated
> > > > with the pages which permits the kernel to clean stuff up on unclean
> > > > application exit. Also there are the obvious issues with permitting
> > > > pinning of unbounded amounts of memory.
> > >
> > > Correct, the driver must be able to determine that the process has died
> > > and clean up after it, so the pinned region in most implementations is
> > > associated with an open file descriptor.
> >
> > How is that association created?
>
>
> There is not a file descrptor, but there is an rnic handle. Both DAPL
> and IT-API require that process death will result in the handle and all
> of its dependent objects being released.
What's an "rnic handle", in Linux terms?
> The rnic handle can always be declared to be a "file descriptor" if
> that makes it follow normal OS conventions more precisiely.
Does that mean that the code has not yet been implemented?
Yes, a Linux fd is appropriate. But we don't have any sane way right now
of saying "you need to run put_page() against all these pages in the
->release() handler". That'll need to be coded by yourselves.
> There is also a need for some form of resource manager to approve
> creation of Memory Regions. Obviously you cannot have multiple
> applications claiming half of physical memory.
The kernel already has considerable resource management capabilities.
Please consider using/extending/generalising those before inventing
anything new. RLIMIT_MEMLOCK would be a starting point.
> But if you merely require the user to have root privileges in order
> to create a Memory Region, and then take a first-come first-served
> attitude, I don't think you end up with something that is truly a
> general purpose capability.
We don't want code in the kernel which will permit hostile unprivileged
users to trivially cause the box to lock up. RLIMIT_MEMLOCK and, if
necessary, CAP_IPC_LOCK sound appropriate here.
> A general purpose RDMA capability requires the ability to indefinitely
> pin large portions of user memory. It makes sense to integrate that
> with OS policy control over resource utilization and to integrate it with
> memory suspend/resume capabilities so that hotplug memory can
> be supported. What you can't do is downgrade a Memory Region so
> that it is no longer a memory region. Doing that means that you are
> not truly supporting RDMA.
next prev parent reply other threads:[~2005-04-26 0:11 UTC|newest]
Thread overview: 144+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-04 22:09 [PATCH][RFC][0/4] InfiniBand userspace verbs implementation Roland Dreier
2005-04-04 22:09 ` [PATCH][RFC][1/4] IB: core changes for userspace verbs Roland Dreier
2005-04-04 22:09 ` [PATCH][RFC][2/4] IB: userspace verbs main module Roland Dreier
2005-04-04 22:09 ` [PATCH][RFC][3/4] IB: userspace verbs mthca changes Roland Dreier
2005-04-04 22:09 ` [PATCH][RFC][4/4] IB: userspace verbs Kconfig/Makefile changes Roland Dreier
2005-04-04 22:49 ` [openib-general] [PATCH][RFC][3/4] IB: userspace verbs mthca changes Tom Duffy
2005-04-04 23:34 ` Roland Dreier
2005-04-21 0:37 ` [PATCH][MTHCA] fix sparc build WAS: " Tom Duffy
2005-04-21 0:38 ` David S. Miller
2005-04-11 14:22 ` [PATCH][RFC][0/4] InfiniBand userspace verbs implementation Troy Benjegerdes
2005-04-11 15:34 ` Roland Dreier
2005-04-11 16:33 ` Troy Benjegerdes
2005-04-11 16:56 ` Roland Dreier
2005-04-11 18:01 ` Troy Benjegerdes
2005-04-11 18:03 ` Roland Dreier
2005-04-12 0:13 ` Andrew Morton
2005-04-12 0:21 ` Roland Dreier
2005-04-12 18:23 ` Michael S. Tsirkin
2005-04-13 18:28 ` Roland Dreier
2005-04-13 19:32 ` Andrew Morton
2005-04-13 1:04 ` [openib-general] " Libor Michalek
2005-04-18 17:15 ` Timur Tabi
2005-04-26 3:31 ` Libor Michalek
2005-05-04 18:27 ` Timur Tabi
2005-05-05 18:48 ` Timur Tabi
2005-05-06 23:08 ` Timur Tabi
2005-05-07 13:18 ` Hugh Dickins
2005-05-07 14:45 ` Timur Tabi
2005-05-07 16:30 ` Hugh Dickins
2005-05-11 20:12 ` William Jordan
2005-05-11 20:42 ` Hugh Dickins
2005-05-11 22:52 ` Andrea Arcangeli
2005-05-11 22:49 ` Andrea Arcangeli
2005-05-11 22:53 ` Timur Tabi
2005-05-11 23:05 ` Andrea Arcangeli
2005-05-05 23:34 ` Libor Michalek
2005-04-18 16:22 ` Timur Tabi
2005-04-18 16:43 ` Christoph Hellwig
2005-04-18 16:45 ` Timur Tabi
2005-04-24 2:44 ` Andrew Morton
2005-04-24 14:23 ` Timur Tabi
2005-04-24 20:53 ` Greg KH
2005-04-24 21:52 ` Timur Tabi
2005-04-25 1:03 ` Greg KH
2005-04-25 4:12 ` Timur Tabi
2005-04-25 13:30 ` Dave Hansen
2005-04-25 13:15 ` Roland Dreier
2005-04-25 13:17 ` Christoph Hellwig
2005-04-25 14:16 ` Roland Dreier
2005-04-25 20:54 ` Andrew Morton
2005-04-25 21:12 ` Roland Dreier
2005-04-25 22:14 ` Andrew Morton
2005-04-25 22:21 ` Timur Tabi
2005-04-25 22:32 ` Andrew Morton
2005-04-25 23:58 ` Roland Dreier
2005-04-26 0:11 ` Andrew Morton
2005-04-26 0:23 ` Roland Dreier
2005-04-26 0:37 ` Andrew Morton
2005-04-26 2:21 ` Timur Tabi
2005-04-26 3:16 ` Andrew Morton
2005-04-26 3:38 ` Timur Tabi
2005-04-26 4:33 ` Andrew Morton
2005-04-26 14:07 ` Timur Tabi
2005-04-26 15:31 ` Roland Dreier
2005-04-26 15:42 ` [openib-general] " Libor Michalek
2005-04-26 15:49 ` Roland Dreier
2005-04-26 19:28 ` Andrew Morton
2005-04-26 20:14 ` Roland Dreier
2005-04-26 20:18 ` Timur Tabi
2005-04-26 20:37 ` Andrew Morton
2005-04-29 14:26 ` Bill Jordan
2005-04-29 15:56 ` Caitlin Bestler
2005-04-29 16:45 ` RDMA memory registration (was: [openib-general] Re: [PATCH][RFC][0/4] InfiniBand userspace verbs implementation) Roland Dreier
2005-04-29 17:23 ` Libor Michalek
2005-04-29 18:22 ` RDMA memory registration Brice Goglin
2005-04-29 18:31 ` Roland Dreier
2005-04-29 19:33 ` [openib-general] " Grant Grundler
2005-05-03 8:42 ` David Addison
2005-05-03 15:36 ` Grant Grundler
2005-04-29 19:43 ` RDMA memory registration (was: [openib-general] Re: [PATCH][RFC][0/4] InfiniBand userspace verbs implementation) Bill Jordan
2005-04-29 19:45 ` RDMA memory registration Roland Dreier
2005-04-29 17:04 ` [openib-general] Re: [PATCH][RFC][0/4] InfiniBand userspace verbs implementation Libor Michalek
2005-04-30 0:31 ` Caitlin Bestler
2005-05-03 18:43 ` Andy Isaacson
2005-05-03 19:04 ` Caitlin Bestler
2005-05-04 18:22 ` William Jordan
2005-05-05 1:27 ` Rik van Riel
2005-05-05 1:57 ` Andy Isaacson
2005-04-26 20:32 ` Andrew Morton
2005-04-26 21:23 ` Roland Dreier
2005-04-27 0:05 ` Andrew Morton
2005-04-27 2:13 ` Roland Dreier
2005-04-27 3:21 ` Caitlin Bestler
2005-04-27 3:15 ` Caitlin Bestler
2005-04-26 2:03 ` IWAMOTO Toshihiro
2005-04-26 2:16 ` Timur Tabi
2005-04-26 2:26 ` [openib-general] " Stephen Langdon
2005-04-25 22:23 ` Timur Tabi
2005-04-25 22:35 ` Andrew Morton
2005-04-25 22:42 ` Timur Tabi
2005-04-25 23:13 ` Andrew Morton
2005-04-25 23:21 ` Timur Tabi
2005-04-25 23:27 ` Andrew Morton
2005-04-26 0:08 ` Roland Dreier
2005-04-25 22:51 ` [openib-general] Re: [PATCH][RFC][0/4] InfiniBand userspace verbsimplementation Bob Woodruff
2005-04-25 23:13 ` Timur Tabi
2005-04-25 23:17 ` Andrew Morton
2005-04-25 23:29 ` Bob Woodruff
2005-04-25 23:17 ` [openib-general] Re: [PATCH][RFC][0/4] InfiniBand userspace verbs implementation Libor Michalek
2005-04-25 23:24 ` Andrew Morton
2005-04-25 23:37 ` Caitlin Bestler
2005-04-26 0:10 ` Andrew Morton [this message]
2005-04-26 3:55 ` Libor Michalek
2005-04-26 0:02 ` Roland Dreier
2005-04-26 6:12 ` Christoph Hellwig
2005-04-26 13:45 ` [openib-general] " Caitlin Bestler
2005-04-26 15:24 ` Timur Tabi
2005-04-25 19:11 ` Andy Isaacson
2005-04-18 16:09 ` Timur Tabi
2005-04-18 16:12 ` Roland Dreier
2005-04-18 16:50 ` Timur Tabi
2005-04-21 19:47 ` Pavel Machek
2005-04-18 16:16 ` Arjan van de Ven
2005-04-18 16:25 ` Timur Tabi
2005-04-18 19:40 ` Arjan van de Ven
2005-04-18 20:00 ` Timur Tabi
2005-04-18 20:05 ` Arjan van de Ven
2005-04-18 20:19 ` Timur Tabi
2005-04-18 20:07 ` [openib-general] " Bernhard Fischer
2005-04-21 2:17 ` Troy Benjegerdes
2005-04-21 3:07 ` Timur Tabi
2005-04-21 17:38 ` Andy Isaacson
2005-04-21 18:39 ` Timur Tabi
2005-04-21 19:56 ` Andy Isaacson
2005-04-21 20:07 ` Timur Tabi
2005-04-21 20:12 ` Chris Wright
2005-04-21 20:14 ` Timur Tabi
2005-04-21 20:25 ` Chris Wright
2005-04-21 20:30 ` Arjan van de Ven
2005-04-22 6:14 ` Greg KH
2005-04-22 17:55 ` Timur Tabi
2005-04-22 18:12 ` Arjan van de Ven
2005-04-29 0:56 ` Andrew Morton
[not found] <3VAeQ-1To-7@gated-at.bofh.it>
[not found] ` <3VNYt-4M4-15@gated-at.bofh.it>
2005-04-22 13:10 ` [openib-general] " Bodo Eggert <harvested.in.lkml@posting.7eggert.dyndns.org>
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20050425171050.5ba25918.akpm@osdl.org \
--to=akpm@osdl.org \
--cc=caitlin.bestler@gmail.com \
--cc=hch@infradead.org \
--cc=libor@topspin.com \
--cc=linux-kernel@vger.kernel.org \
--cc=openib-general@openib.org \
--cc=timur.tabi@ammasso.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).