On Thu, Sep 04, 2025 at 01:57:29PM +0100, Kevin Brodsky wrote: Hi Kevin,
> When the lazy MMU mode was introduced eons ago, it wasn't made clear > whether such a sequence was legal: > > arch_enter_lazy_mmu_mode() > ... > arch_enter_lazy_mmu_mode() > ... > arch_leave_lazy_mmu_mode() > ... > arch_leave_lazy_mmu_mode() I did not take too deep - sorry if you already answered this. Quick question - whether a concern Ryan expressed is addressed in general case? https://lore.kernel.org/all/3cad01ea-b704-4156-807e-7a8364391...@arm.com/ enter_lazy_mmu for_each_pte { read/modify-write pte alloc_page enter_lazy_mmu make page valid exit_lazy_mmu write_to_page } exit_lazy_mmu <quote> This example only works because lazy_mmu doesn't support nesting. The "make page valid" operation is completed by the time of the inner exit_lazy_mmu so that the page can be accessed in write_to_page. If nesting was supported, the inner exit_lazy_mmu would become a nop and write_to_page would explode. </quote> ... Thanks!
