On Thu, Jan 20, 2022 at 5:46 PM David Hildenbrand <david@xxxxxxxxxx> wrote: > > I'm, not concerned about fork(), I'm concerned about other false positives. Without a fork(), you won't have the THP marked for COW, so is it really an issue? > Here is what I currently have, I hope that makes sense: >From a quick look, that patch looks fine to me, but there might be something I'm missing... And who knows what odd usage patterns there might be in this area. The whole odd Android thing with forking that zygote process. Because that zygote thing _does_ use THP, I think, and it's where the wrong-way COW thing mattered. Obviously doing COW is the right thing to do, and that case doesn't want any sharing of pages (all copies), but it might be worth at least checking that it works and there isn't some odd performance gotcha. Linus