On 7/22/21 3:24 AM, Matthew Wilcox wrote:

On Wed, Jul 14, 2021 at 02:48:30PM -0700, Andrew Morton wrote:

quoted

On Wed, 14 Jul 2021 20:35:28 +0100 Joao Martins [off-list ref] wrote:

quoted

This series, attempts at minimizing 'struct page' overhead by
pursuing a similar approach as Muchun Song series "Free some vmemmap
pages of hugetlb page"[0] but applied to devmap/ZONE_DEVICE which is now
in mmotm. 

[0] https://lore.kernel.org/linux-mm/20210308102807.59745-1-songmuchun@bytedance.com/ (local)

[0] is now in mainline.

This patch series looks like it'll clash significantly with the folio
work and it is pretty thinly reviewed, so I think I'll take a pass for
now.  Matthew, thoughts?

I had a look through it, and I don't see anything that looks like it'll
clash with the folio patches.  

FWIW, I had tried this last week, and this series applies cleanly on top of your 130+
patch series for Folios.

The folio work really touches the page
cache for now, and this seems mostly to touch the devmap paths.

/me nods -- it really is about devmap infra for usage in device-dax for persistent memory.

Perhaps I should do s/pagemaps/devmap/ throughout the series to avoid confusion.

It would be nice to convert the devmap code to folios too, but that
can wait.  The mess with page refcounts needs to be sorted out first.

I suppose you refer to fixing the current zone-device elevated page ref count?

https://lore.kernel.org/linux-mm/20210717192135.9030-3-alex.sierra@amd.com/ (local)