On Thu, Dec 22, 2011 at 01:50:46PM +0800, Li Zefan wrote: > > @@ -2091,6 +2010,10 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader) > > * rcu or tasklist locked. instead, build an array of all threads in the > > * group - group_rwsem prevents new threads from appearing, and if > > * threads exit, this will just be an over-estimate. > > + * > > + * While creating the list, also make sure css_sets exist for all > > + * threads to be migrated. we use find_css_set, which allocates a new > > + * one if necessary. > > */ > > group_size = get_nr_threads(leader); > > /* flex_array supports very large thread-groups better than kmalloc. */ > > @@ -2137,6 +2060,12 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader) > > /* nothing to do if this task is already in the cgroup */ > > if (ent.cgrp == cgrp) > > continue; > > + ent.cg = find_css_set(tsk->cgroups, cgrp); > > unfortunately This won't work, because we are holding tasklist_lock. I believe we can remove tasklist_lock now (in a seperate patch). It was there in order to protect while_each_thread() against exec but now we have threadgroup_lock(). I think we only need to use rcu_read_lock() to protect against concurrent removal in exit. > > + if (!ent.cg) { > > + retval = -ENOMEM; > > + group_size = i; > > + goto out_list_teardown; > > + } > > retval = flex_array_put(group, i, &ent, GFP_ATOMIC); > > BUG_ON(retval != 0); > > i++; -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html