From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Once a THP is added to the page cache, it cannot be dropped via
/proc/sys/vm/drop_caches. Fix this issue with proper handling in
invalidate_mapping_pages().
Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Tested-by: Song Liu <songliubraving@xxxxxx>
Signed-off-by: Song Liu <songliubraving@xxxxxx>
---
mm/truncate.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/mm/truncate.c b/mm/truncate.c
index 8563339041f6..dd9ebc1da356 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -592,6 +592,16 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping,
unlock_page(page);
continue;
}
+
+ /* Take a pin outside pagevec */
+ get_page(page);
+
+ /*
+ * Drop extra pins before trying to invalidate
+ * the huge page.
+ */
+ pagevec_remove_exceptionals(&pvec);
+ pagevec_release(&pvec);
}
ret = invalidate_inode_page(page);
@@ -602,6 +612,8 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping,
*/
if (!ret)
deactivate_file_page(page);
+ if (PageTransHuge(page))
+ put_page(page);
count += ret;
}
pagevec_remove_exceptionals(&pvec);
--
2.17.1
