提交 9f2115f9 编写于 作者: T Tejun Heo 提交者: Linus Torvalds

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: NTejun Heo <tj@kernel.org>
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Reviewed-by: NVladimir Davydov <vdavydov@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
上级 64219994
......@@ -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;
}
......
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