On Thu, 31 Aug 2017, Christoph Hellwig wrote: > The whole VMA games here look entirely bogus you can't just drop > and reacquire mmap_sem for example. > And splitting vmas looks just > as promblematic. I didn't just decide to do that on a whim. I spent quite some time looking at page fault code paths and make sure it is fine to reaquire the lock. There are existing code paths that drop the lock entirely and return with no locks so this is already expected by the core code. > As a minimum you really must see the linux-mm list can get some > feedback there. Good point. You added linux-mm to CC so I'll wait for their comments. Nicolas