From 67e465a77ba658635309ee00b367bec6555ea544 Mon Sep 17 00:00:00 2001 From: Balbir Singh Date: Thu, 7 Feb 2008 00:13:54 -0800 Subject: Memory controller: task migration Allow tasks to migrate from one cgroup to the other. We migrate mm_struct's mem_cgroup only when the thread group id migrates. Signed-off-by: Balbir Singh Cc: Pavel Emelianov Cc: Paul Menage Cc: Peter Zijlstra Cc: "Eric W. Biederman" Cc: Nick Piggin Cc: Kirill Korotaev Cc: Herbert Poetzl Cc: David Rientjes Cc: Vaidyanathan Srinivasan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) (limited to 'mm/memcontrol.c') diff --git a/mm/memcontrol.c b/mm/memcontrol.c index ebca767292dc..b25df2a9d024 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -326,11 +326,46 @@ static int mem_cgroup_populate(struct cgroup_subsys *ss, ARRAY_SIZE(mem_cgroup_files)); } +static void mem_cgroup_move_task(struct cgroup_subsys *ss, + struct cgroup *cont, + struct cgroup *old_cont, + struct task_struct *p) +{ + struct mm_struct *mm; + struct mem_cgroup *mem, *old_mem; + + mm = get_task_mm(p); + if (mm == NULL) + return; + + mem = mem_cgroup_from_cont(cont); + old_mem = mem_cgroup_from_cont(old_cont); + + if (mem == old_mem) + goto out; + + /* + * Only thread group leaders are allowed to migrate, the mm_struct is + * in effect owned by the leader + */ + if (p->tgid != p->pid) + goto out; + + css_get(&mem->css); + rcu_assign_pointer(mm->mem_cgroup, mem); + css_put(&old_mem->css); + +out: + mmput(mm); + return; +} + struct cgroup_subsys mem_cgroup_subsys = { .name = "memory", .subsys_id = mem_cgroup_subsys_id, .create = mem_cgroup_create, .destroy = mem_cgroup_destroy, .populate = mem_cgroup_populate, + .attach = mem_cgroup_move_task, .early_init = 1, }; -- cgit v1.2.3