MADV_FREE needs pmd_dirty and pmd_mkclean for detecting recent
overwrite of the contents since MADV_FREE syscall is called for
THP page.
This patch adds pmd_dirty and pmd_mkclean for THP page MADV_FREE
support.
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Acked-by: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>