From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx193.postini.com [74.125.245.193]) by kanga.kvack.org (Postfix) with SMTP id 73B7A6B0002 for ; Tue, 16 Apr 2013 00:20:52 -0400 (EDT) Received: by mail-ie0-f171.google.com with SMTP id e11so77567iej.30 for ; Mon, 15 Apr 2013 21:20:51 -0700 (PDT) Message-ID: <516CD19C.6080508@gmail.com> Date: Tue, 16 Apr 2013 12:20:44 +0800 From: Simon Jeons MIME-Version: 1.0 Subject: Re: [LSF/MM TOPIC] Hardware initiated paging of user process pages, hardware access to the CPU page tables of user processes References: <5114DF05.7070702@mellanox.com> <516BBCB5.7050303@gmail.com> In-Reply-To: Content-Type: multipart/alternative; boundary="------------000405040503050909090509" Sender: owner-linux-mm@kvack.org List-ID: To: Jerome Glisse Cc: Michel Lespinasse , Shachar Raindel , lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, Andrea Arcangeli , Roland Dreier , Haggai Eran , Or Gerlitz , Sagi Grimberg , Liran Liss This is a multi-part message in MIME format. --------------000405040503050909090509 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Hi Jerome, On 04/15/2013 11:38 PM, Jerome Glisse wrote: > On Mon, Apr 15, 2013 at 4:39 AM, Simon Jeons > wrote: > > Hi Jerome, > On 02/10/2013 12:29 AM, Jerome Glisse wrote: > > On Sat, Feb 9, 2013 at 1:05 AM, Michel Lespinasse > > wrote: > > On Fri, Feb 8, 2013 at 3:18 AM, Shachar Raindel > > wrote: > > Hi, > > We would like to present a reference implementation > for safely sharing > memory pages from user space with the hardware, > without pinning. > > We will be happy to hear the community feedback on our > prototype > implementation, and suggestions for future improvements. > > We would also like to discuss adding features to the > core MM subsystem to > assist hardware access to user memory without pinning. > > This sounds kinda scary TBH; however I do understand the > need for such > technology. > > I think one issue is that many MM developers are > insufficiently aware > of such developments; having a technology presentation > would probably > help there; but traditionally LSF/MM sessions are more > interactive > between developers who are already quite familiar with the > technology. > I think it would help if you could send in advance a detailed > presentation of the problem and the proposed solutions > (and then what > they require of the MM layer) so people can be better > prepared. > > And first I'd like to ask, aren't IOMMUs supposed to > already largely > solve this problem ? (probably a dumb question, but that > just tells > you how much you need to explain :) > > For GPU the motivation is three fold. With the advance of GPU > compute > and also with newer graphic program we see a massive increase > in GPU > memory consumption. We easily can reach buffer that are bigger > than > 1gbytes. So the first motivation is to directly use the memory the > user allocated through malloc in the GPU this avoid copying > 1gbytes of > data with the cpu to the gpu buffer. The second and mostly > important > > > The pinned memory you mentioned is the memory user allocated or > the memory of gpu buffer? > > > Memory user allocated, we don't want to pin this memory. After this idea merged, we don't need to allocate memory for integrated GPU buffer and discrete GPU don't need to have its own memory, correct? > > Cheers, > Jerome --------------000405040503050909090509 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit
Hi Jerome,
On 04/15/2013 11:38 PM, Jerome Glisse wrote:
On Mon, Apr 15, 2013 at 4:39 AM, Simon Jeons <simon.jeons@gmail.com> wrote:
Hi Jerome,
On 02/10/2013 12:29 AM, Jerome Glisse wrote:
On Sat, Feb 9, 2013 at 1:05 AM, Michel Lespinasse <walken@google.com> wrote:
On Fri, Feb 8, 2013 at 3:18 AM, Shachar Raindel <raindel@mellanox.com> wrote:
Hi,

We would like to present a reference implementation for safely sharing
memory pages from user space with the hardware, without pinning.

We will be happy to hear the community feedback on our prototype
implementation, and suggestions for future improvements.

We would also like to discuss adding features to the core MM subsystem to
assist hardware access to user memory without pinning.
This sounds kinda scary TBH; however I do understand the need for such
technology.

I think one issue is that many MM developers are insufficiently aware
of such developments; having a technology presentation would probably
help there; but traditionally LSF/MM sessions are more interactive
between developers who are already quite familiar with the technology.
I think it would help if you could send in advance a detailed
presentation of the problem and the proposed solutions (and then what
they require of the MM layer) so people can be better prepared.

And first I'd like to ask, aren't IOMMUs supposed to already largely
solve this problem ? (probably a dumb question, but that just tells
you how much you need to explain :)
For GPU the motivation is three fold. With the advance of GPU compute
and also with newer graphic program we see a massive increase in GPU
memory consumption. We easily can reach buffer that are bigger than
1gbytes. So the first motivation is to directly use the memory the
user allocated through malloc in the GPU this avoid copying 1gbytes of
data with the cpu to the gpu buffer. The second and mostly important

The pinned memory you mentioned is the memory user allocated or the memory of gpu buffer?

Memory user allocated, we don't want to pin this memory.

After this idea merged, we don't need to allocate memory for integrated GPU buffer and discrete GPU don't need to have its own memory, correct?


Cheers,
Jerome

--------------000405040503050909090509-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org