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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: "David S. Miller" <davem@davemloft.net>
Cc: grundler@parisc-linux.org, linux-pci@atrey.karlin.mff.cuni.cz,
	Linux Kernel list <linux-kernel@vger.kernel.org>,
	Greg KH <greg@kroah.com>,
	bjorn.helgaas@hp.com, "David S. Miller" <davem@redhat.com>
Subject: Re: pci-sysfs resource mmap broken (and PATCH)
Date: Thu, 28 Apr 2005 17:46:38 +1000	[thread overview]
Message-ID: <1114674398.7183.257.camel@gaston> (raw)
In-Reply-To: <20050428002209.12bd3f37.davem@davemloft.net>

On Thu, 2005-04-28 at 00:22 -0700, David S. Miller wrote:
> On Thu, 28 Apr 2005 17:21:19 +1000
> Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
> 
> > I have a real net big performance improvement on X by doing that
> > trick ... the sysfs mmap API doesn't really provide a mean to do
> > it explicitely from userland (unlike the ioctl with the old proc api)
> 
> You can refine your test to "if PCI class is display or VGA" and the
> prefetchability is set in the BAR, then elide the guard PTE
> protection bit.

Yes, but I was also thinking about some of those Myrinet kind of things
who also provide large PCI shared memory region ...

I may end up adding an explicit list of classes/vid/did that are
"allowed" to use the trick to avoid problems.

Ben.



  reply	other threads:[~2005-04-28  7:49 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-04-26  5:33 pci-sysfs resource mmap broken Benjamin Herrenschmidt
2005-04-26  6:09 ` Benjamin Herrenschmidt
2005-04-26  6:36   ` Greg KH
2005-04-26  9:24   ` Russell King
2005-04-26 16:30 ` Grant Grundler
2005-04-26 22:47   ` Benjamin Herrenschmidt
2005-04-27  3:55     ` Grant Grundler
2005-04-27  4:30       ` Benjamin Herrenschmidt
2005-04-27  4:28         ` David S. Miller
2005-04-27  4:39           ` Benjamin Herrenschmidt
2005-04-27  4:46     ` pci-sysfs resource mmap broken (and PATCH) Benjamin Herrenschmidt
2005-04-27 23:13     ` Benjamin Herrenschmidt
2005-04-28  5:33       ` Grant Grundler
2005-04-28  5:37         ` David S. Miller
2005-04-28  6:39           ` Benjamin Herrenschmidt
2005-04-28  6:50             ` David S. Miller
2005-04-28  7:21               ` Benjamin Herrenschmidt
2005-04-28  7:22                 ` David S. Miller
2005-04-28  7:46                   ` Benjamin Herrenschmidt [this message]
2005-04-28 15:11               ` Grant Grundler
2005-04-28 22:47                 ` Benjamin Herrenschmidt
2005-04-28 23:38                   ` Grant Grundler
2005-04-29 15:42                     ` David S. Miller
2005-04-29 22:16                       ` Jesse Barnes
2005-04-28  6:35         ` Benjamin Herrenschmidt
2005-05-03  5:37           ` pci-sysfs resource mmap broken PATCH#2 Benjamin Herrenschmidt

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