James Bottomley wrote:
On Tue, 2007-08-21 at 17:34 -0700, [EMAIL PROTECTED] wrote:
The term "posted DMA" is used to describe this behavior in the Altix
Device Driver Writer's Guide, but it may be confusing things here.
Maybe a better term will suggest itself if I can clarify....
OK, but posted DMA has a pretty specific meaning in terms of PCI, hence
the confusion.
Maybe it would be more better to refer to this as 'out of order DMA'?
On Altix, DMA from a device isn't guaranteed to arrive in host memory
in the order it was sent from the device. This reordering can happen
in the NUMA interconnect (it's specifically not a PCI reordering.)
This is mmiowb and read_relaxed() again, isn't it?
I believe it's the same problem, except this time it's when exposing
structures to userland.
Cheers,
Jes
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