[PATCH -V7 RESEND 10/21] swap: Support to count THP swapin and its fallback

2 new /proc/vmstat fields are added, "thp_swapin" and "thp_swapin_fallback" to count swapin a THP from swap device in one piece and fallback to normal page swapin. Signed-off-by: "Huang, Ying" Cc: "Kirill A. Shutemov" Cc: Andrea Arcangeli Cc: Michal Hocko Cc: Johannes Weiner Cc: Shaohua Li

[PATCH -V7 RESEND 10/21] swap: Support to count THP swapin and its fallback

2 new /proc/vmstat fields are added, "thp_swapin" and "thp_swapin_fallback" to count swapin a THP from swap device in one piece and fallback to normal page swapin. Signed-off-by: "Huang, Ying" Cc: "Kirill A. Shutemov" Cc: Andrea Arcangeli Cc: Michal Hocko Cc: Johannes Weiner Cc: Shaohua Li