Re: [PATCH v8 2/9] mmap: make mlock_future_check() global

David Hildenbrand
2020-11-10T17:17:45Z

On 10.11.20 16:14, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> It will be used by the upcoming secret memory implementation.
>
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
> mm/internal.h | 3 +++
> mm/mmap.c | 5 ++---
> 2 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/mm/internal.h b/mm/internal.h
> index c43ccdddb0f6..ae146a260b14 100644
> --- a/mm/internal.h
> +++ b/mm/internal.h
> @@ -348,6 +348,9 @@ static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
> extern void mlock_vma_page(struct page *page);
> extern unsigned int munlock_vma_page(struct page *page);
>
> +extern int mlock_future_check(struct mm_struct *mm, unsigned long flags,
> + unsigned long len);
> +
> /*
> * Clear the page's PageMlocked(). This can be useful in a situation where
> * we want to unconditionally remove a page from the pagecache -- e.g.,
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 61f72b09d990..c481f088bd50 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -1348,9 +1348,8 @@ static inline unsigned long round_hint_to_min(unsigned long hint)
> return hint;
> }
>
> -static inline int mlock_future_check(struct mm_struct *mm,
> - unsigned long flags,
> - unsigned long len)
> +int mlock_future_check(struct mm_struct *mm, unsigned long flags,
> + unsigned long len)
> {
> unsigned long locked, lock_limit;
>
>

So, an interesting question is if you actually want to charge secretmem
pages against mlock now, or if you want a dedicated secretmem cgroup
controller instead?

--
Thanks,

David / dhildenb