On Tue, May 15, 2018 at 01:43:23PM +0300, Boaz Harrosh wrote: > Yes I know, but that is exactly the point of this flag. I know that this > address is only ever accessed from a single core. Because it is an mmap (vma) > of an O_TMPFILE-exclusive file created in a core-pinned thread and I allow > only that thread any kind of access to this vma. Both the filehandle and the > mmaped pointer are kept on the thread stack and have no access from outside. > > So the all point of this flag is the kernel driver telling mm that this > address is enforced to only be accessed from one core-pinned thread. What happens when the userspace part -- there is one, right, how else do you get an mm to stick a vma in -- simply does a full address range probe scan? Something like this really needs a far more detailed Changelog that explains how its to be used and how it is impossible to abuse. Esp. that latter is _very_ important.
