Re: [PATCH v2 0/7] Nesting support for lazy MMU mode

Lorenzo Stoakes
2025-09-08T16:56:53Z

On Mon, Sep 08, 2025 at 08:39:24AM +0100, Kevin Brodsky wrote:
> 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()
>
> It seems fair to say that nested calls to
> arch_{enter,leave}_lazy_mmu_mode() were not expected, and most
> architectures never explicitly supported it.

This is compiling with CONFIG_USERFAULTFD at all commits and series is
compiling with allmodconfig plus all mm selftests are passing so from my
side this looks good, thanks for addressing issues and rebasing! :)

Cheers, Lorenzo