On Oct 29, 2022, at 1:15 PM, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > (b) we could move the "page_remove_rmap()" into the "flush-and-free" path too > > And (b) would be fairly easy - same model as that dirty bit patch, > just a 'do page_remove_rmap too' - except page_remove_rmap() wants the > vma as well (and we delay the TLB flush over multiple vma's, so it's > not just a "save vma in mmu_gather”). (b) sounds reasonable and may potentially allow future performance improvements (batching, doing stuff without locks). It does appear to break a potential hidden assumption that rmap is removed while the ptl is acquired (at least in the several instances I samples). Yet, anyhow page_vma_mapped_walk() checks the PTE before calling the function, so it should be fine. I’ll give it a try.
