Re: [RFC PATCH 02/11] rust: add `pages` module for handling page allocation

[Matthew Wilcox]

On Fri, May 05, 2023 at 06:42:02AM +0200, Andreas Hindborg wrote:
> 
> Matthew Wilcox <willy@xxxxxxxxxxxxx> writes:
> 
> > On Wed, May 03, 2023 at 11:06:59AM +0200, Andreas Hindborg wrote:
> >> From: Andreas Hindborg <a.hindborg@xxxxxxxxxxx>
> >> 
> >> This patch adds support for working with pages of order 0. Support for pages
> >> with higher order is deferred. Page allocation flags are fixed in this patch.
> >> Future work might allow the user to specify allocation flags.
> >> 
> >> This patch is a heavily modified version of code available in the rust tree [1],
> >> primarily adding support for multiple page mapping strategies.
> >
> > This also seems misaligned with the direction of Linux development.
> > Folios are the future, pages are legacy.  Please, ask about what's
> > going on before wasting time on the past.
> 
> I see, thanks for the heads up! In this case I wanted to do an
> apples-apples comparison to the C null_blk driver. Since that is using
> kmap I wanted to have that. But let's bind to the folio_* APIs in the
> future, that would make sense.

Well, kmap() is essentially a no-op on 64-bit systems, so it's not
terribly relevant to doing a comparison.