mm: memcontrol: prepare move_account for removal of private page type counters

When memcg uses the generic vmstat counters, it doesn't need to do
anything at charging and uncharging time.  It does, however, need to
migrate counts when pages move to a different cgroup in move_account.

Prepare the move_account function for the arrival of NR_FILE_PAGES,
NR_ANON_MAPPED, NR_ANON_THPS etc.  by having a branch for files and a
branch for anon, which can then divided into sub-branches.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: http://lkml.kernel.org/r/20200508183105.225460-8-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ff45bef46ffe1b66f6b061ca9d8d3de49548c20f..f82ae37237609afff73472c2f9cb123c892b339a 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5434,7 +5434,6 @@ static int mem_cgroup_move_account(struct page *page,
        struct pglist_data *pgdat;
        unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
        int ret;
-       bool anon;
 
        VM_BUG_ON(from == to);
        VM_BUG_ON_PAGE(PageLRU(page), page);
@@ -5452,25 +5451,27 @@ static int mem_cgroup_move_account(struct page *page,
        if (page->mem_cgroup != from)
                goto out_unlock;
 
-       anon = PageAnon(page);
-
        pgdat = page_pgdat(page);
        from_vec = mem_cgroup_lruvec(from, pgdat);
        to_vec = mem_cgroup_lruvec(to, pgdat);
 
        lock_page_memcg(page);
 
-       if (!anon && page_mapped(page)) {
-               __mod_lruvec_state(from_vec, NR_FILE_MAPPED, -nr_pages);
-               __mod_lruvec_state(to_vec, NR_FILE_MAPPED, nr_pages);
-       }
+       if (!PageAnon(page)) {
+               if (page_mapped(page)) {
+                       __mod_lruvec_state(from_vec, NR_FILE_MAPPED, -nr_pages);
+                       __mod_lruvec_state(to_vec, NR_FILE_MAPPED, nr_pages);
+               }
 
-       if (!anon && PageDirty(page)) {
-               struct address_space *mapping = page_mapping(page);
+               if (PageDirty(page)) {
+                       struct address_space *mapping = page_mapping(page);
 
-               if (mapping_cap_account_dirty(mapping)) {
-                       __mod_lruvec_state(from_vec, NR_FILE_DIRTY, -nr_pages);
-                       __mod_lruvec_state(to_vec, NR_FILE_DIRTY, nr_pages);
+                       if (mapping_cap_account_dirty(mapping)) {
+                               __mod_lruvec_state(from_vec, NR_FILE_DIRTY,
+                                                  -nr_pages);
+                               __mod_lruvec_state(to_vec, NR_FILE_DIRTY,
+                                                  nr_pages);
+                       }
                }
        }