[PATCH 07/18] mm: memcontrol: prepare move_account for removal of private page type counters

Johannes Weiner
2020-04-20T22:12:54Z

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>
---
mm/memcontrol.c | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e3e8913a5b28..ac6f2b073a5a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5374,7 +5374,6 @@ 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);
@@ -5392,25 +5391,27 @@ 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);
+ }
}
}

--
2.26.0