Re: [PATCH 1/2] hugetlbfs: extend hugetlb_vma_lock to private VMAs

[Matthew Wilcox]

On Tue, Sep 19, 2023 at 10:16:09PM -0400, riel@xxxxxxxxxxx wrote:
> From: Rik van Riel <riel@xxxxxxxxxxx>
> 
> Extend the locking scheme used to protect shared hugetlb mappings
> from truncate vs page fault races, in order to protect private
> hugetlb mappings (with resv_map) against MADV_DONTNEED.
> 
> Add a read-write semaphore to the resv_map data structure, and
> use that from the hugetlb_vma_(un)lock_* functions, in preparation
> for closing the race between MADV_DONTNEED and page faults.

This feels an awful lot like the invalidate_lock in struct address_space
which was recently added by Jan Kara.