The real advantage of userfaults if compared to regular virtual memory
management of mremap/mprotect is that the userfaults in all their
operations never involve heavyweight structures like vmas (in fact the
-``userfaultfd`` runtime load never takes the mmap_sem for writing).
+``userfaultfd`` runtime load never takes the mmap_lock for writing).
Vmas are not suitable for page- (or hugepage) granular fault tracking
when dealing with virtual address spaces that could span