On Fri, Nov 06, 2020 at 01:26:50PM -0800, Ralph Campbell wrote:
On 11/6/20 12:03 AM, Christoph Hellwig wrote:
I hate the extra pin count magic here. IMHO we really need to finish off the series to get rid of the extra references on the ZONE_DEVICE pages first.
First, thanks for the review comments.
I don't like the extra refcount either, that is why I tried to fix that up before resending this series. However, you didn't like me just fixing the refcount only for device private pages and I don't know the dax/pmem code and peer-to-peer PCIe uses of ZONE_DEVICE pages well enough to say how long it will take me to fix all the use cases. So I wanted to make progress on the THP migration code in the mean time.
I think P2P is pretty trivial, given that ZONE_DEVICE pages are used like a normal memory allocator. DAX is the interesting case, any specific help that you need with that?