From: KAMEZAWA Hiroyuki remove_list/add_list uses page_cgroup_zoneinfo() in it. So, it's called twice before and after lock. mz = page_cgroup_zoneinfo(); lock(); mz = page_cgroup_zoneinfo(); .... unlock(); And address of mz never changes. This is not good. This patch fixes this behavior. Signed-off-by: KAMEZAWA Hiroyuki Cc: Balbir Singh Cc: Pavel Emelyanov Signed-off-by: Andrew Morton --- mm/memcontrol.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff -puN mm/memcontrol.c~memcg-remove-redundant-function-calls mm/memcontrol.c --- a/mm/memcontrol.c~memcg-remove-redundant-function-calls +++ a/mm/memcontrol.c @@ -275,10 +275,10 @@ static void unlock_page_cgroup(struct pa bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup); } -static void __mem_cgroup_remove_list(struct page_cgroup *pc) +static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz, + struct page_cgroup *pc) { int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE; - struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc); if (from) MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) -= 1; @@ -289,10 +289,10 @@ static void __mem_cgroup_remove_list(str list_del_init(&pc->lru); } -static void __mem_cgroup_add_list(struct page_cgroup *pc) +static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz, + struct page_cgroup *pc) { int to = pc->flags & PAGE_CGROUP_FLAG_ACTIVE; - struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc); if (!to) { MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1; @@ -618,7 +618,7 @@ retry: mz = page_cgroup_zoneinfo(pc); spin_lock_irqsave(&mz->lru_lock, flags); - __mem_cgroup_add_list(pc); + __mem_cgroup_add_list(mz, pc); spin_unlock_irqrestore(&mz->lru_lock, flags); unlock_page_cgroup(page); @@ -674,7 +674,7 @@ void mem_cgroup_uncharge_page(struct pag if (--(pc->ref_cnt) == 0) { mz = page_cgroup_zoneinfo(pc); spin_lock_irqsave(&mz->lru_lock, flags); - __mem_cgroup_remove_list(pc); + __mem_cgroup_remove_list(mz, pc); spin_unlock_irqrestore(&mz->lru_lock, flags); page_assign_page_cgroup(page, NULL); @@ -736,7 +736,7 @@ void mem_cgroup_page_migration(struct pa mz = page_cgroup_zoneinfo(pc); spin_lock_irqsave(&mz->lru_lock, flags); - __mem_cgroup_remove_list(pc); + __mem_cgroup_remove_list(mz, pc); spin_unlock_irqrestore(&mz->lru_lock, flags); page_assign_page_cgroup(page, NULL); @@ -748,7 +748,7 @@ void mem_cgroup_page_migration(struct pa mz = page_cgroup_zoneinfo(pc); spin_lock_irqsave(&mz->lru_lock, flags); - __mem_cgroup_add_list(pc); + __mem_cgroup_add_list(mz, pc); spin_unlock_irqrestore(&mz->lru_lock, flags); unlock_page_cgroup(newpage); _