On Wed, Dec 23, 2020 at 4:13 PM Christoph Hellwig <h...@infradead.org> wrote:
>
> On Wed, Dec 23, 2020 at 02:32:07PM +0800, Yongji Xie wrote:
> > Now I want to map/unmap some pages in an userland vma dynamically. The
> > vm_insert_page() is being used for mapping. In the unmapping case, it
> > looks like the zap_page_range() does what I want. So I export it.
> > Otherwise, we need some ways to notify userspace to trigger it with
> > madvise(MADV_DONTNEED), which might not be able to meet all our needs.
> > For example, unmapping some pages in a memory shrinker function.
> >
> > So I'd like to know what's the limitation to use zap_page_range() in a
> > module. And if we can't use it in a module, is there any acceptable
> > way to achieve that?
>
> I think the anser is: don't play funny games with unmapped outside of
> munmap.  Especially as synchronization is very hard to get right.

OK, I will try to let userspace do this.

Thanks,
Yongji

Reply via email to