Re: alpha iommu fixes

[Ivan Kokshaysky]

On Sun, May 20, 2001 at 04:40:13AM +0200, Andrea Arcangeli wrote:
> I was only talking about when you get the "pci_map_sg failed" because
> you have not 3 but 300 scsi disks connected to your system and you are
> writing to all them at the same time allocating zillons of pte, and one
> of your drivers (possibly not even a storage driver) is actually not
> checking the reval of the pci_map_* functions. You don't need a pte
> memleak to trigger it, even regardless of the fact I grown the dynamic
> window to 1G which makes it 8 times harder to trigger than in mainline.

I think you're too pessimistic. Don't mix "disks" and "controllers" --
SCSI adapter with 10 drives attached is a single DMA agent, not 10 agents.

If you're so concerned about Big Iron, go ahead and implement 64-bit PCI
support, it would be right long-term solution. I'm pretty sure that
high-end servers use mostly this kind of hardware.

Oh, well. This doesn't mean that I'm disagreed with what you said. :-)
Driver writers must realize that pci mappings are limited resources.

Ivan.