Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit d9654322 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Linus Torvalds
Browse files

thp: increase split_huge_page() success rate 



During freeze_page(), we remove the page from rmap.  It munlocks the
page if it was mlocked.  clear_page_mlock() uses thelru cache, which
temporary pins the page.

Let's drain the lru cache before checking page's count vs.  mapcount.
The change makes mlocked page split on first attempt, if it was not
pinned by somebody else.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 49071d43

mm/huge_memory.c

+6 −0
Original line number Diff line number Diff line
@@ -3201,6 +3201,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) 
	struct page *head = compound_head(page);

	struct anon_vma *anon_vma;

	int count, mapcount, ret;

	bool mlocked;



	VM_BUG_ON_PAGE(is_huge_zero_page(page), page);

	VM_BUG_ON_PAGE(!PageAnon(page), page);
@@ -3231,9 +3232,14 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) 
		goto out_unlock;

	}



	mlocked = PageMlocked(page);

	freeze_page(anon_vma, head);

	VM_BUG_ON_PAGE(compound_mapcount(head), head);



	/* Make sure the page is not on per-CPU pagevec as it takes pin */

	if (mlocked)

		lru_add_drain();



	/* Prevent deferred_split_scan() touching ->_count */

	spin_lock(&split_queue_lock);

	count = page_count(head);