Since readahead page will be charged on memcg too. We don't need to
check this exception now. Rmove them is safe as all user pages are
charged before use.
Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: cgroups@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
mm/memcontrol.c | 21 ++++-----------------
1 file changed, 4 insertions(+), 17 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e84c2b5596f2..9e44ae22d591 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1322,12 +1322,7 @@ struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgd
}
memcg = page->mem_cgroup;
- /*
- * Swapcache readahead pages are added to the LRU - and
- * possibly migrated - before they are charged.
- */
- if (!memcg)
- memcg = root_mem_cgroup;
+ VM_BUG_ON_PAGE(!memcg, page);
mz = mem_cgroup_page_nodeinfo(memcg, page);
lruvec = &mz->lruvec;
@@ -6897,10 +6892,8 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage)
if (newpage->mem_cgroup)
return;
- /* Swapcache readahead pages can get replaced before being charged */
memcg = oldpage->mem_cgroup;
- if (!memcg)
- return;
+ VM_BUG_ON_PAGE(!memcg, oldpage);
/* Force-charge the new page. The old one will be freed soon */
nr_pages = thp_nr_pages(newpage);
@@ -7094,10 +7087,7 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
return;
memcg = page->mem_cgroup;
-
- /* Readahead page, never charged */
- if (!memcg)
- return;
+ VM_BUG_ON_PAGE(!memcg, page);
/*
* In case the memcg owning these pages has been offlined and doesn't
@@ -7158,10 +7148,7 @@ int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
return 0;
memcg = page->mem_cgroup;
-
- /* Readahead page, never charged */
- if (!memcg)
- return 0;
+ VM_BUG_ON_PAGE(!memcg, page);
if (!entry.val) {
memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
--
1.8.3.1
