Re: [PATCH v2 0/5] mm: reduce mmap_lock contention and improve page fault performance

Matthew Wilcox
2026-04-30T12:37:28Z

On Thu, Apr 30, 2026 at 12:04:22PM +0800, Barry Song (Xiaomi) wrote:
> (1) If we need to wait for I/O completion, we still drop the per-VMA lock, as
> current page fault handling already does. Holding it for too long may introduce
> various priority inversion issues on mobile devices. After I/O completes, we
> retry the page fault with the per-VMA lock, rather than falling back to
> mmap_lock.

You're going to have to do better than that. You know I hate the
additional complexity you're adding. You need to explain why my idea of
ripping out all the complexity now that we have per-VMA locks doesn't
work.