Matthew Wilcox wrote: > On Fri, Feb 23, 2024 at 03:50:33PM -0800, Dan Williams wrote: > > Certainly something like that would have satisified this sanity test use > > case. I will note that mm_account_fault() would need some help to figure > > out the size of the page table entry that got installed. Maybe > > extensions to vm_fault_reason to add VM_FAULT_P*D? That compliments > > VM_FAULT_FALLBACK to indicate whether, for example, the fallback went > > from PUD to PMD, or all the way back to PTE. > > ugh, no, it's more complicated than that. look at the recent changes to > set_ptes(). we can now install PTEs of many different sizes, depending > on the architecture. someday i look forward to supporting all the page > sizes on parisc (4k, 16k, 64k, 256k, ... 4G) Nice! There are enough bits in vm_fault_t to represent many page sizes instead of the entry type as I suggested, but I would defer to you or Dave on how to make "installed pte size" generically traceable per Dave's suggestion.