Re: [PATCH RFC v2 1/2] mm: Don't skip swap entry even if zap_details specified

[Peter Xu]

On Sun, Jan 23, 2022 at 10:51:57PM -0800, Hugh Dickins wrote:
> I don't know of any problem that needs fixing with the zero page:
> how do you suppose the zero page gets into a truncatable or hole-punchable
> mapping?  We use it for read faults in anonymous mappings.  And I told the
> story of how once-upon-a-time it could get inserted into any mapping by
> reading from /dev/zero, but that odd case was dropped years ago.  And I
> am open to (even encouraging) a change to make use of zero page for read
> faults of holes in shmem: but that's potential future work, which would
> require some changes elsewhere (though perhaps none here: the zero page
> could never be used for the result of a COW).
> 
> Please explain the zero page problem you hope to fix here.

After I tried to learn the old/new worlds of zero page somehow I thought there
can be zero pfns installed, but it seems not at all..

Please ignore above, sorry for the noise.

-- 
Peter Xu