Re: [PATCH v8 1/1] f2fs: dax: implement direct access

[Christoph Hellwig]

On Wed, Jul 26, 2017 at 09:53:07AM -0700, Dan Williams wrote:
> It allows for opt-in for applications, or administrators of those
> applications, that know the type of access.

That's BS.  We need to provide the best possible way to access the
media to an application.  And whether that's DAX or the page cache
is an implementation detail that should not matter to the application.

Which doesn't mean there shouldn't be ways to override the default
that the kernel chose based on hardware details, but it's certainly
not something for the application to hardcode, but something for
the adminstrator to decide.