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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2016-01-15 16:54:43 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-15 17:56:32 -0800
commitd965432234db94ee8e185f8fd8e3181bed7459fd (patch)
treeb24228d9bd6ef31b1b710327933c3ce334b85a63
parent49071d436b51b58aeaf7abcd1877f38ca0146e31 (diff)
downloadlinux-d965432234db94ee8e185f8fd8e3181bed7459fd.tar.bz2
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: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Sasha Levin <sasha.levin@oracle.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/huge_memory.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index a0b910a0c2cb..882b04449904 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -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);