On Thu, Oct 01, 2020 at 11:17:13AM -0700, Ralph Campbell wrote: > This is still an RFC because after looking at the pmem/dax code some > more, I realized that the ZONE_DEVICE struct pages are being inserted > into the process' page tables with vmf_insert_mixed() and a zero > refcount on the ZONE_DEVICE struct page. This is sort of OK because > insert_pfn() increments the reference count on the pgmap which is what > prevents memunmap_pages() from freeing the struct pages and it doesn't > check for a non-zero struct page reference count. > But, any calls to get_page() will hit the VM_BUG_ON_PAGE() that > checks for a reference count == 0. This seems to have gone quiet. What needs to happen to resurrect this?
