If move_charge flag is set, memcg tries to move memory charges to the destnation css. The current implementation migrates memory whenever any thread of a process is migrated making the behavior somewhat arbitrary. Let's tie memory operations to the threadgroup leader so that memory is migrated only when the leader is migrated. While this is a behavior change, given the inherent fuziness, this change is not too likely to be noticed and allows us to clearly define who owns the memory (always the leader) and helps the planned atomic multi-process migration. Signed-off-by: Tejun Heo <tj@xxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxx> --- mm/memcontrol.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b1b834d..74fcea3 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5014,6 +5014,9 @@ static int mem_cgroup_can_attach(struct cgroup_subsys_state *css, return 0; p = cgroup_taskset_first(tset); + if (!thread_group_leader(p)) + return 0; + from = mem_cgroup_from_task(p); VM_BUG_ON(from == memcg); -- 2.4.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>