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-rw-r--r--include/linux/cgroup-defs.h1
-rw-r--r--include/linux/cgroup.h1
-rw-r--r--kernel/cgroup/cgroup.c44
3 files changed, 39 insertions, 7 deletions
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 77258d276f93..1615b9c17e02 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -216,6 +216,7 @@ struct css_set {
*/
struct list_head tasks;
struct list_head mg_tasks;
+ struct list_head dying_tasks;
/* all css_task_iters currently walking this cset */
struct list_head task_iters;
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 05ed2a209e74..0297f930a56e 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -60,6 +60,7 @@ struct css_task_iter {
struct list_head *task_pos;
struct list_head *tasks_head;
struct list_head *mg_tasks_head;
+ struct list_head *dying_tasks_head;
struct css_set *cur_cset;
struct css_set *cur_dcset;
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 035aee466bbf..a7df319c2e9a 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -739,6 +739,7 @@ struct css_set init_css_set = {
.dom_cset = &init_css_set,
.tasks = LIST_HEAD_INIT(init_css_set.tasks),
.mg_tasks = LIST_HEAD_INIT(init_css_set.mg_tasks),
+ .dying_tasks = LIST_HEAD_INIT(init_css_set.dying_tasks),
.task_iters = LIST_HEAD_INIT(init_css_set.task_iters),
.threaded_csets = LIST_HEAD_INIT(init_css_set.threaded_csets),
.cgrp_links = LIST_HEAD_INIT(init_css_set.cgrp_links),
@@ -1213,6 +1214,7 @@ static struct css_set *find_css_set(struct css_set *old_cset,
cset->dom_cset = cset;
INIT_LIST_HEAD(&cset->tasks);
INIT_LIST_HEAD(&cset->mg_tasks);
+ INIT_LIST_HEAD(&cset->dying_tasks);
INIT_LIST_HEAD(&cset->task_iters);
INIT_LIST_HEAD(&cset->threaded_csets);
INIT_HLIST_NODE(&cset->hlist);
@@ -4399,15 +4401,18 @@ static void css_task_iter_advance_css_set(struct css_task_iter *it)
it->task_pos = NULL;
return;
}
- } while (!css_set_populated(cset));
+ } while (!css_set_populated(cset) && !list_empty(&cset->dying_tasks));
if (!list_empty(&cset->tasks))
it->task_pos = cset->tasks.next;
- else
+ else if (!list_empty(&cset->mg_tasks))
it->task_pos = cset->mg_tasks.next;
+ else
+ it->task_pos = cset->dying_tasks.next;
it->tasks_head = &cset->tasks;
it->mg_tasks_head = &cset->mg_tasks;
+ it->dying_tasks_head = &cset->dying_tasks;
/*
* We don't keep css_sets locked across iteration steps and thus
@@ -4446,6 +4451,8 @@ static void css_task_iter_skip(struct css_task_iter *it,
static void css_task_iter_advance(struct css_task_iter *it)
{
+ struct task_struct *task;
+
lockdep_assert_held(&css_set_lock);
repeat:
if (it->task_pos) {
@@ -4462,17 +4469,32 @@ repeat:
if (it->task_pos == it->tasks_head)
it->task_pos = it->mg_tasks_head->next;
if (it->task_pos == it->mg_tasks_head)
+ it->task_pos = it->dying_tasks_head->next;
+ if (it->task_pos == it->dying_tasks_head)
css_task_iter_advance_css_set(it);
} else {
/* called from start, proceed to the first cset */
css_task_iter_advance_css_set(it);
}
- /* if PROCS, skip over tasks which aren't group leaders */
- if ((it->flags & CSS_TASK_ITER_PROCS) && it->task_pos &&
- !thread_group_leader(list_entry(it->task_pos, struct task_struct,
- cg_list)))
- goto repeat;
+ if (!it->task_pos)
+ return;
+
+ task = list_entry(it->task_pos, struct task_struct, cg_list);
+
+ if (it->flags & CSS_TASK_ITER_PROCS) {
+ /* if PROCS, skip over tasks which aren't group leaders */
+ if (!thread_group_leader(task))
+ goto repeat;
+
+ /* and dying leaders w/o live member threads */
+ if (!atomic_read(&task->signal->live))
+ goto repeat;
+ } else {
+ /* skip all dying ones */
+ if (task->flags & PF_EXITING)
+ goto repeat;
+ }
}
/**
@@ -6009,6 +6031,7 @@ void cgroup_exit(struct task_struct *tsk)
if (!list_empty(&tsk->cg_list)) {
spin_lock_irq(&css_set_lock);
css_set_move_task(tsk, cset, NULL, false);
+ list_add_tail(&tsk->cg_list, &cset->dying_tasks);
cset->nr_tasks--;
WARN_ON_ONCE(cgroup_task_frozen(tsk));
@@ -6034,6 +6057,13 @@ void cgroup_release(struct task_struct *task)
do_each_subsys_mask(ss, ssid, have_release_callback) {
ss->release(task);
} while_each_subsys_mask();
+
+ if (use_task_css_set_links) {
+ spin_lock_irq(&css_set_lock);
+ css_set_skip_task_iters(task_css_set(task), task);
+ list_del_init(&task->cg_list);
+ spin_unlock_irq(&css_set_lock);
+ }
}
void cgroup_free(struct task_struct *task)