On 25.09.21 22:54, Nadav Amit wrote:
From: Nadav Amit <namit@xxxxxxxxxx> Currently, using mprotect() to unprotect a memory region or uffd to unprotect a memory region causes a TLB flush. At least on x86, as protection is promoted, no TLB flush is needed. Add an arch-specific pte_may_need_flush() which tells whether a TLB flush is needed based on the old PTE and the new one. Implement an x86 pte_may_need_flush(). For x86, PTE protection promotion or changes of software bits does require a flush, also add logic that considers the dirty-bit. Changes to the access-bit do not trigger a TLB flush, although architecturally they should, as Linux considers the access-bit as a hint.
Is the added LOC worth the benefit? IOW, do we have some benchmark that really benefits from that?
-- Thanks, David / dhildenb
