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Date: Fri, 22 Feb 2002 12:49:10 +0100
From: Steffen Persvold <sp@scali.com>
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To: "Jeff V. Merkey" <jmerkey@vger.timpanogas.org>
CC: "David S. Miller" <davem@redhat.com>, jgarzik@mandrakesoft.com,
        linux-kernel@vger.kernel.org, jmerkey@timpanogas.org
Subject: Re: ioremap()/PCI sickness in 2.4.18-rc2
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"Jeff V. Merkey" wrote:
> 
> On Wed, Feb 20, 2002 at 07:44:58PM +0100, Steffen Persvold wrote:
> > On Wed, 20 Feb 2002, David S. Miller wrote:
> >
> > >    From: Jeff Garzik <jgarzik@mandrakesoft.com>
> > >    Date: Wed, 20 Feb 2002 12:26:12 -0500
> > >
> > >    type abuse aside, and alpha bugs aside, this looks ok... what is the
> > >    value of as->msize?
> > >
> > > Jeff and Jeff, the problem is one of two things:
> > >
> > > 1) when you have ~2GB of memory the vmalloc pool is very small
> > >    and this it the same place ioremap allocations come from
> > >
> > > 2) the BIOS or Linus is not assigning resources of the device
> > >    properly, or it simple can't because the available PCI MEM space
> > >    with this much memory is too small
> > >
> > > I note that one of the resources of the card is 16MB or so.
> >
> > Hi guys,
> >
> > There is actually no need to have all three regions mapped at all times is
> > there Jeff ? In the Scali ICM driver we actually doesn't ioremap() the
> > prefetchable space at all because this is done with the mmap() method to
> > the userspace clients. If you have a kernel space client though ioremap()
> > is used, but only the parts of it that is needed (based on the number of
> > nodes in the cluser and the shared memory size per node).
> >
> > Regards,
> >
> 
> I am not using the adapters in user space, I am using them in kernel
> space with a distributed RAID agent and file system.  This is a general
> issue with Hugo's SISCI and IRM drivers and Linux.  They all need to work
> in every configuration.  If it works with less than 1 GB is should work
> with > 1GB of memory.
> 
> I am looking through get_vm_area() since this is where the bug is.  Your
> Scali drivers are not the Dolphin released IRM/SISCI but custom drivers
> you guys sell with **YOUR** software versions, and they are far from
> general purpose.
> 

Jeff,

I really don't think you're in a position to say wether the Scali driver is
general purpose or not, but in any case this issue is OT. My point is that it
is not a good idea to keep the prefetchable area mapped at all times. The ICM
driver also has kernel clients (e.g. a ethernet emulation driver) and they only
ioremap() the areas which is needed based upon the number of nodes in the
cluster they communicate with (and only a few Kbytes is mapped from each node). 

Regards,
-- 
  Steffen Persvold   | Scalable Linux Systems |   Try out the world's best
 mailto:sp@scali.com |  http://www.scali.com  | performing MPI implementation:
Tel: (+47) 2262 8950 |   Olaf Helsets vei 6   |      - ScaMPI 1.13.8 -
Fax: (+47) 2262 8951 |   N0621 Oslo, NORWAY   | >320MBytes/s and <4uS latency
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