On Mon, Oct 11, 2021 at 09:06:37AM +0100, Christoph Hellwig wrote: > 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. 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.