Re: [RFC v4 0/3] mm: zap pages with read mmap_sem in munmap for large mapping

From: Kirill A. Shutemov
Date: Wed Jul 11 2018 - 07:13:19 EST


On Wed, Jul 11, 2018 at 12:33:12PM +0200, Michal Hocko wrote:
> this is not a small change for something that could be achieved
> from the userspace trivially (just call madvise before munmap - library
> can hide this). Most workloads will even not care about races because
> they simply do not play tricks with mmaps and userspace MM. So why do we
> want to put the additional complexity into the kernel?

As I said before, kernel latency issues have to be addressed in kernel.
We cannot rely on userspace being kind here.

--
Kirill A. Shutemov