On 9/15/20 7:32 AM, Matthew Wilcox wrote:

On Tue, Sep 15, 2020 at 08:59:23PM +0800, Muchun Song wrote:

quoted

This patch series will free some vmemmap pages(struct page structures)
associated with each hugetlbpage when preallocated to save memory.

It would be lovely to be able to do this.  Unfortunately, it's completely
impossible right now.  Consider, for example, get_user_pages() called
on the fifth page of a hugetlb page.

Yeah, exactly.

Does this series survive the in-kernel selftests/?  If so, sounds like
we need to add a new selftest.