memcg: remove redundant code

- try_get_mem_cgroup_from_mm() calls rcu_read_lock/unlock by itself, so we
  don't have to call them in task_in_mem_cgroup().
- *mz is not used in __mem_cgroup_uncharge_common().
- we don't have to call lookup_page_cgroup() in mem_cgroup_end_migration()
  after we've cleared PCG_MIGRATION of @oldpage.
- remove empty comment.
- remove redundant empty line in mem_cgroup_cache_charge().

Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Daisuke Nishimura 2010-08-10 18:02:59 -07:00 committed by Linus Torvalds
parent 2bd9bb206b
commit bd0d24bfe8

View File

@ -840,9 +840,7 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
struct mem_cgroup *curr = NULL;
task_lock(task);
rcu_read_lock();
curr = try_get_mem_cgroup_from_mm(task->mm);
rcu_read_unlock();
task_unlock(task);
if (!curr)
return 0;
@ -2092,7 +2090,6 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
if (!(gfp_mask & __GFP_WAIT)) {
struct page_cgroup *pc;
pc = lookup_page_cgroup(page);
if (!pc)
return 0;
@ -2286,7 +2283,6 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
{
struct page_cgroup *pc;
struct mem_cgroup *mem = NULL;
struct mem_cgroup_per_zone *mz;
if (mem_cgroup_disabled())
return NULL;
@ -2340,7 +2336,6 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
* special functions.
*/
mz = page_cgroup_zoneinfo(pc);
unlock_page_cgroup(pc);
memcg_check_events(mem, page);
@ -2652,11 +2647,8 @@ void mem_cgroup_end_migration(struct mem_cgroup *mem,
ClearPageCgroupMigration(pc);
unlock_page_cgroup(pc);
if (unused != oldpage)
pc = lookup_page_cgroup(unused);
__mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE);
pc = lookup_page_cgroup(used);
/*
* If a page is a file cache, radix-tree replacement is very atomic
* and we can skip this check. When it was an Anon page, its mapcount
@ -3800,8 +3792,6 @@ static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
return 0;
}
/*
*/
static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
struct cftype *cft, u64 val)
{