mm: memcg: move pc lookup point to commit_charge()
None of the callsites actually need the page_cgroup descriptor
themselves, so just pass the page and do the look up in there.
We already had two bugs (6568d4a 'mm: memcg: update the correct soft
limit tree during migration' and 'memcg: fix Bad page state after
replace_page_cache') where the passed page and pc were not referring
to the same page frame.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index b868def..31ab9c3 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2476,10 +2476,10 @@
static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg,
struct page *page,
unsigned int nr_pages,
- struct page_cgroup *pc,
enum charge_type ctype,
bool lrucare)
{
+ struct page_cgroup *pc = lookup_page_cgroup(page);
struct zone *uninitialized_var(zone);
bool was_on_lru = false;
bool anon;
@@ -2716,7 +2716,6 @@
{
struct mem_cgroup *memcg = NULL;
unsigned int nr_pages = 1;
- struct page_cgroup *pc;
bool oom = true;
int ret;
@@ -2730,11 +2729,10 @@
oom = false;
}
- pc = lookup_page_cgroup(page);
ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom);
if (ret == -ENOMEM)
return ret;
- __mem_cgroup_commit_charge(memcg, page, nr_pages, pc, ctype, false);
+ __mem_cgroup_commit_charge(memcg, page, nr_pages, ctype, false);
return 0;
}
@@ -2831,16 +2829,13 @@
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg,
enum charge_type ctype)
{
- struct page_cgroup *pc;
-
if (mem_cgroup_disabled())
return;
if (!memcg)
return;
cgroup_exclude_rmdir(&memcg->css);
- pc = lookup_page_cgroup(page);
- __mem_cgroup_commit_charge(memcg, page, 1, pc, ctype, true);
+ __mem_cgroup_commit_charge(memcg, page, 1, ctype, true);
/*
* Now swap is on-memory. This means this page may be
* counted both as mem and swap....double count.
@@ -3298,14 +3293,13 @@
* page. In the case new page is migrated but not remapped, new page's
* mapcount will be finally 0 and we call uncharge in end_migration().
*/
- pc = lookup_page_cgroup(newpage);
if (PageAnon(page))
ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
else if (page_is_file_cache(page))
ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
else
ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
- __mem_cgroup_commit_charge(memcg, newpage, 1, pc, ctype, false);
+ __mem_cgroup_commit_charge(memcg, newpage, 1, ctype, false);
return ret;
}
@@ -3392,8 +3386,7 @@
* the newpage may be on LRU(or pagevec for LRU) already. We lock
* LRU while we overwrite pc->mem_cgroup.
*/
- pc = lookup_page_cgroup(newpage);
- __mem_cgroup_commit_charge(memcg, newpage, 1, pc, type, true);
+ __mem_cgroup_commit_charge(memcg, newpage, 1, type, true);
}
#ifdef CONFIG_DEBUG_VM