Re: [Lsf-pc] [LSF/MM TOPIC] The end of the DAX experiment

From: Dan Williams
Date: Thu Feb 14 2019 - 15:20:25 EST

On Thu, Feb 14, 2019 at 12:09 PM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
> On Thu, Feb 14, 2019 at 11:31:24AM -0800, Dan Williams wrote:
> > On Thu, Feb 14, 2019 at 11:10 AM Jerome Glisse <jglisse@xxxxxxxxxx> wrote:
> > > I am just again working on my struct page mapping patchset as well as
> > > the generic page write protection that sits on top. I hope to be able
> > > to post the v2 in couple weeks. You can always look at my posting last
> > > year to see more details.
> >
> > Yes, I have that in mind as one of the contenders. However, it's not
> > clear to me that its a suitable fit for filesystem-reflink. Others
> > have floated the 'page proxy' idea, so it would be good to discuss the
> > merits of the general approaches.
> ... and my preferred option of putting pfn entries in the page cache.

Another option to include the discussion.

> Or is that what you meant by "page proxy"?

Page proxy would be an object that a filesystem could allocate to
point back to a single physical 'struct page *'. The proxy would
contain an override for page->index.