Re: [PATCH 1/3] blk-mq: add an API to estimate hardware queue node

[Christoph Hellwig]

On Fri, Mar 25, 2016 at 02:36:30PM -0700, Shaohua Li wrote:
> we allocate most data structure in device's node, but some data
> structures are not for DMA and mostly used by specific cpus/node which
> could diff from device's node. Allocating such hot data in device's
> node doesn't make sense. Add an API to estimate hardware queue node.
> This can be used before blk-mq actually establishes the mapping. This
> API runs slow, but it only used in initialization time.

I think this is the wrong way around.  I've got some proprotype code
that just leaves the cpu assignments to the drivers and picks it up
in blk-mq.  Give me a few days to post it..