From 3e14a57b2416b7c94189b95baffd673cf5e0d0a3 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Wed, 6 Sep 2017 16:22:37 -0700 Subject: [PATCH] memcg, THP, swap: support move mem cgroup charge for THP swapped out PTE mapped THP (Transparent Huge Page) will be ignored when moving memory cgroup charge. But for THP which is in the swap cache, the memory cgroup charge for the swap of a tail-page may be moved in current implementation. That isn't correct, because the swap charge for all sub-pages of a THP should be moved together. Following the processing of the PTE mapped THP, the mem cgroup charge moving for the swap entry for a tail-page of a THP is ignored too. Link: http://lkml.kernel.org/r/20170724051840.2309-9-ying.huang@intel.com Signed-off-by: "Huang, Ying" Cc: Johannes Weiner Cc: Minchan Kim Cc: Michal Hocko Cc: Andrea Arcangeli Cc: "Kirill A . Shutemov" Cc: Dan Williams Cc: Hugh Dickins Cc: Jens Axboe Cc: Rik van Riel Cc: Ross Zwisler [for brd.c, zram_drv.c, pmem.c] Cc: Shaohua Li Cc: Vishal L Verma Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 3d3f7b1686ac..2ae315e4d9f6 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4639,8 +4639,11 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma, if (!ret || !target) put_page(page); } - /* There is a swap entry and a page doesn't exist or isn't charged */ - if (ent.val && !ret && + /* + * There is a swap entry and a page doesn't exist or isn't charged. + * But we cannot move a tail-page in a THP. + */ + if (ent.val && !ret && (!page || !PageTransCompound(page)) && mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) { ret = MC_TARGET_SWAP; if (target) -- 2.20.1