On Thu, Jan 26, 2017 at 02:57:48PM +0300, Kirill A. Shutemov wrote: > For filesystems that wants to be write-notified (has mkwrite), we will > encount write-protection faults for huge PMDs in shared mappings. > > The easiest way to handle them is to clear the PMD and let it refault as > wriable. ... of course, the filesystem could implement ->pmd_fault, and then it wouldn't hit this case ...