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authorDavid S. Miller <davem@davemloft.net>2019-06-18 05:48:13 +0300
committerDavid S. Miller <davem@davemloft.net>2019-06-18 06:20:36 +0300
commit13091aa30535b719e269f20a7bc34002bf5afae5 (patch)
treebd17956c3ce606a119fadbd43bfa1c0c10006984 /include/linux/cgroup.h
parentf97252a8c33f0e02f4ffbf61dc94cd38164007bc (diff)
parent29f785ff76b65696800b75c3d8e0b58e603bb1d0 (diff)
downloadlinux-13091aa30535b719e269f20a7bc34002bf5afae5.tar.xz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Honestly all the conflicts were simple overlapping changes, nothing really interesting to report. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/cgroup.h')
-rw-r--r--include/linux/cgroup.h14
1 files changed, 12 insertions, 2 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 49e8facf7c4a..93614d17ecc9 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -43,6 +43,9 @@
/* walk all threaded css_sets in the domain */
#define CSS_TASK_ITER_THREADED (1U << 1)
+/* internal flags */
+#define CSS_TASK_ITER_SKIPPED (1U << 16)
+
/* a css_task_iter should be treated as an opaque object */
struct css_task_iter {
struct cgroup_subsys *ss;
@@ -57,6 +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;
@@ -487,7 +491,7 @@ static inline struct cgroup_subsys_state *task_css(struct task_struct *task,
*
* Find the css for the (@task, @subsys_id) combination, increment a
* reference on and return it. This function is guaranteed to return a
- * valid css.
+ * valid css. The returned css may already have been offlined.
*/
static inline struct cgroup_subsys_state *
task_get_css(struct task_struct *task, int subsys_id)
@@ -497,7 +501,13 @@ task_get_css(struct task_struct *task, int subsys_id)
rcu_read_lock();
while (true) {
css = task_css(task, subsys_id);
- if (likely(css_tryget_online(css)))
+ /*
+ * Can't use css_tryget_online() here. A task which has
+ * PF_EXITING set may stay associated with an offline css.
+ * If such task calls this function, css_tryget_online()
+ * will keep failing.
+ */
+ if (likely(css_tryget(css)))
break;
cpu_relax();
}