Re: [PATCH 1/3 v3] dma: document dma_{un}map_{single|sg}_attrs() interface

akepner
2008-03-05T18:14:45Z

On Fri, Feb 29, 2008 at 12:37:56PM -0600, James Bottomley wrote:
> ....
> To be honest, I still don't like the name. SYNC_ON_WRITE is the SN2
> implementation. What it's actually doing is implementing strict
> ordering semantics. I think it should really be
> DMA_ATTR_STRICT_ORDERING (with a corresponding
> DMA_ATTR_RELAXED_ORDERING)....

I've been thinking about a new name, but don't like
DMA_ATTR_STRICT_ORDERING.

What I'm trying to do is to establish order (across
a NUMA fabric) of DMA to different memory regions, i.e.,
DMA to memory region A forces all outstanding DMA (to
memory regions B, C,....) to complete first.

DMA_ATTR_STRICT_ORDERING sounds like a PCI thing to me,
and this is a NUMA interconnect thing.

--
Arthur