| Message ID | 20210330101531.82752-2-songmuchun@bytedance.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Use obj_cgroup APIs to charge the LRU pages | expand |
On Tue, Mar 30, 2021 at 06:15:17PM +0800, Muchun Song wrote: > The pages aren't accounted at the root level, so do not charge the page > to the root memcg in page replacement. Although we do not display the > value (mem_cgroup_usage) so there shouldn't be any actual problem, but > there is a WARN_ON_ONCE in the page_counter_cancel(). Who knows if it > will trigger? So it is better to fix it. > > Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 249bf6b4d94c..d0c4f6e91e17 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6936,9 +6936,11 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage) /* Force-charge the new page. The old one will be freed soon */ nr_pages = thp_nr_pages(newpage); - page_counter_charge(&memcg->memory, nr_pages); - if (do_memsw_account()) - page_counter_charge(&memcg->memsw, nr_pages); + if (!mem_cgroup_is_root(memcg)) { + page_counter_charge(&memcg->memory, nr_pages); + if (do_memsw_account()) + page_counter_charge(&memcg->memsw, nr_pages); + } css_get(&memcg->css); commit_charge(newpage, memcg);
The pages aren't accounted at the root level, so do not charge the page to the root memcg in page replacement. Although we do not display the value (mem_cgroup_usage) so there shouldn't be any actual problem, but there is a WARN_ON_ONCE in the page_counter_cancel(). Who knows if it will trigger? So it is better to fix it. Signed-off-by: Muchun Song <songmuchun@bytedance.com> --- mm/memcontrol.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)