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authorTejun Heo <tj@kernel.org>2015-09-09 01:01:10 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-09-09 01:35:28 +0300
commit9f2115f93b88e5e8d48b87b153e36a537afb58cb (patch)
tree9e978b13e9fb24d33908ca6e9a066c3645d9f2fd /mm
parent64219994898c8689c3d57668996f476f8c2d398c (diff)
downloadlinux-9f2115f93b88e5e8d48b87b153e36a537afb58cb.tar.xz
memcg: restructure mem_cgroup_can_attach()
Restructure it to lower nesting level and help the planned threadgroup leader iteration changes. This is pure reorganization. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/memcontrol.c61
1 files changed, 32 insertions, 29 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6935f77589e7..191d8aa5da71 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4834,10 +4834,12 @@ static void mem_cgroup_clear_mc(void)
static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
struct cgroup_taskset *tset)
{
- struct task_struct *p = cgroup_taskset_first(tset);
- int ret = 0;
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+ struct mem_cgroup *from;
+ struct task_struct *p;
+ struct mm_struct *mm;
unsigned long move_flags;
+ int ret = 0;
/*
* We are now commited to this value whatever it is. Changes in this
@@ -4845,36 +4847,37 @@ static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
* So we need to save it, and keep it going.
*/
move_flags = READ_ONCE(memcg->move_charge_at_immigrate);
- if (move_flags) {
- struct mm_struct *mm;
- struct mem_cgroup *from = mem_cgroup_from_task(p);
+ if (!move_flags)
+ return 0;
- VM_BUG_ON(from == memcg);
+ p = cgroup_taskset_first(tset);
+ from = mem_cgroup_from_task(p);
- mm = get_task_mm(p);
- if (!mm)
- return 0;
- /* We move charges only when we move a owner of the mm */
- if (mm->owner == p) {
- VM_BUG_ON(mc.from);
- VM_BUG_ON(mc.to);
- VM_BUG_ON(mc.precharge);
- VM_BUG_ON(mc.moved_charge);
- VM_BUG_ON(mc.moved_swap);
-
- spin_lock(&mc.lock);
- mc.from = from;
- mc.to = memcg;
- mc.flags = move_flags;
- spin_unlock(&mc.lock);
- /* We set mc.moving_task later */
-
- ret = mem_cgroup_precharge_mc(mm);
- if (ret)
- mem_cgroup_clear_mc();
- }
- mmput(mm);
+ VM_BUG_ON(from == memcg);
+
+ mm = get_task_mm(p);
+ if (!mm)
+ return 0;
+ /* We move charges only when we move a owner of the mm */
+ if (mm->owner == p) {
+ VM_BUG_ON(mc.from);
+ VM_BUG_ON(mc.to);
+ VM_BUG_ON(mc.precharge);
+ VM_BUG_ON(mc.moved_charge);
+ VM_BUG_ON(mc.moved_swap);
+
+ spin_lock(&mc.lock);
+ mc.from = from;
+ mc.to = memcg;
+ mc.flags = move_flags;
+ spin_unlock(&mc.lock);
+ /* We set mc.moving_task later */
+
+ ret = mem_cgroup_precharge_mc(mm);
+ if (ret)
+ mem_cgroup_clear_mc();
}
+ mmput(mm);
return ret;
}