On Mon, Oct 11, 2021 at 09:06:37AM +0100, Christoph Hellwig wrote:Hi, Matthew
Can we please just get proper pagecache THP (through folios) merged
instead of piling hacks over hacks here? The whole readonly THP already
was more than painful enough due to all the hacks involved.
This was my initial reaction too.
But read the patches. They're nothing to do with the implementation of
THP / folios in the page cache. They're all to make sure that mappings
are PMD aligned.
At the beginning, we don't introduce the new sysfs interface, just re-use 'transparent_hugepage/enabled'. But In some production system, they
I think there's a lot to criticise in the patches (eg, a system-wide
setting is probably a bad idea. and a lot of this stuff seems to
be fixing userspace bugs in the kernel). But let's criticise what's
actually in the patches, because these are problems that exist regardless
of RO_THP vs folios.