Re: [PATCH v5] DAX: enable iostat for read/write

[Jeff Moyer]

Christoph Hellwig <hch@xxxxxxxxxxxxx> writes:

> On Thu, Jan 12, 2017 at 11:38:48AM -0700, Toshi Kani wrote:
>> DAX IO path does not support iostat, but its metadata IO path does.
>> Therefore, iostat shows metadata IO statistics only, which has been
>> confusing to users.
>> 
>> Add iostat support to the DAX read/write path.
>> 
>> Note, iostat still does not support the DAX mmap path as it allows
>> user applications to access directly.
>
> NAK.  DAX I/O should not be accounted for block device statistics.

Agreed, this is a layering violation.

Cheers,
Jeff