# Re: \[PATCH v10 7/7\] mm: Don't split THP page when syscall is called

- From: Kirill A. Shutemov \<hidden\>
- Date: 2014-07-08 09:48:33 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2014/07/4289386
- Thread: https://ratatoskr.run/linux-mm/2014/07/4288002/t.md

```text
On Tue, Jul 08, 2014 at 10:30:38AM +0900, Minchan Kim wrote:
> Actually, I did but found no problem except CONFIG_DEBUG_VM but rollback
> after peeking [1].
> When I read the description in detail by your review, I think we can remove
> BUG_ON(PageTransHuge(page)) in try_to_unmap and go with no split for lazyfree
> page because they are not in swapcache any more so the assumption of [1] is
> not valid. Will do it in next revision.

No. try_to_unmap() knows nothing about PMDs, so page_check_address() will
always return NULL for THP and you will not unmap anything.

-- 
 Kirill A. Shutemov

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