diff options
| -rw-r--r-- | kernel/cpuset.c | 41 |
1 files changed, 15 insertions, 26 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 918bee9dc7a2..6868c1e78917 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -752,7 +752,7 @@ static int update_cpumask(struct cpuset *cs, char *buf) trialcs = *cs; /* - * An empty cpus_allowed is ok if there are no tasks in the cpuset. + * An empty cpus_allowed is ok only if the cpuset has no tasks. * Since cpulist_parse() fails on an empty mask, we special case * that parsing. The validate_change() call ensures that cpusets * with tasks have cpus. @@ -809,7 +809,7 @@ static int update_cpumask(struct cpuset *cs, char *buf) * so that the migration code can allocate pages on these nodes. * * Call holding cgroup_mutex, so current's cpuset won't change - * during this call, as cgroup_mutex holds off any attach_task() + * during this call, as manage_mutex holds off any cpuset_attach() * calls. Therefore we don't need to take task_lock around the * call to guarantee_online_mems(), as we know no one is changing * our task's cpuset. @@ -1661,8 +1661,8 @@ void cpuset_do_move_task(struct task_struct *tsk, struct cgroup_scanner *scan) * @from: cpuset in which the tasks currently reside * @to: cpuset to which the tasks will be moved * - * Called with manage_sem held - * callback_mutex must not be held, as attach_task() will take it. + * Called with cgroup_mutex held + * callback_mutex must not be held, as cpuset_attach() will take it. * * The cgroup_scan_tasks() function will scan all the tasks in a cgroup, * calling callback functions for each. @@ -1689,18 +1689,18 @@ static void move_member_tasks_to_cpuset(struct cpuset *from, struct cpuset *to) * last CPU or node from a cpuset, then move the tasks in the empty * cpuset to its next-highest non-empty parent. * - * The parent cpuset has some superset of the 'mems' nodes that the - * newly empty cpuset held, so no migration of memory is necessary. - * - * Called with both manage_sem and callback_sem held + * Called with cgroup_mutex held + * callback_mutex must not be held, as cpuset_attach() will take it. */ static void remove_tasks_in_empty_cpuset(struct cpuset *cs) { struct cpuset *parent; - /* the cgroup's css_sets list is in use if there are tasks - in the cpuset; the list is empty if there are none; - the cs->css.refcnt seems always 0 */ + /* + * The cgroup's css_sets list is in use if there are tasks + * in the cpuset; the list is empty if there are none; + * the cs->css.refcnt seems always 0. + */ if (list_empty(&cs->css.cgroup->css_sets)) return; @@ -1709,14 +1709,8 @@ static void remove_tasks_in_empty_cpuset(struct cpuset *cs) * has online cpus, so can't be empty). */ parent = cs->parent; - while (cpus_empty(parent->cpus_allowed)) { - /* - * this empty cpuset should now be considered to - * have been used, and therefore eligible for - * release when empty (if it is notify_on_release) - */ + while (cpus_empty(parent->cpus_allowed)) parent = parent->parent; - } move_member_tasks_to_cpuset(cs, parent); } @@ -1725,10 +1719,6 @@ static void remove_tasks_in_empty_cpuset(struct cpuset *cs) * Walk the specified cpuset subtree and look for empty cpusets. * The tasks of such cpuset must be moved to a parent cpuset. * - * Note that such a notify_on_release cpuset must have had, at some time, - * member tasks or cpuset descendants and cpus and memory, before it can - * be a candidate for release. - * * Called with cgroup_mutex held. We take callback_mutex to modify * cpus_allowed and mems_allowed. * @@ -1764,8 +1754,8 @@ static void scan_for_empty_cpusets(const struct cpuset *root) cpus_and(cp->cpus_allowed, cp->cpus_allowed, cpu_online_map); nodes_and(cp->mems_allowed, cp->mems_allowed, node_states[N_HIGH_MEMORY]); - if ((cpus_empty(cp->cpus_allowed) || - nodes_empty(cp->mems_allowed))) { + if (cpus_empty(cp->cpus_allowed) || + nodes_empty(cp->mems_allowed)) { /* Move tasks from the empty cpuset to a parent */ mutex_unlock(&callback_mutex); remove_tasks_in_empty_cpuset(cp); @@ -1773,7 +1763,6 @@ static void scan_for_empty_cpusets(const struct cpuset *root) } } mutex_unlock(&callback_mutex); - return; } /* @@ -2207,7 +2196,7 @@ void __cpuset_memory_pressure_bump(void) * - Used for /proc/<pid>/cpuset. * - No need to task_lock(tsk) on this tsk->cpuset reference, as it * doesn't really matter if tsk->cpuset changes after we read it, - * and we take cgroup_mutex, keeping attach_task() from changing it + * and we take cgroup_mutex, keeping cpuset_attach() from changing it * anyway. */ static int proc_cpuset_show(struct seq_file *m, void *unused_v) |
