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-rw-r--r--include/linux/cgroup.h34
1 files changed, 29 insertions, 5 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 2357733a0a8..88e86346072 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -141,15 +141,36 @@ enum {
CGRP_WAIT_ON_RMDIR,
};
+/* which pidlist file are we talking about? */
+enum cgroup_filetype {
+ CGROUP_FILE_PROCS,
+ CGROUP_FILE_TASKS,
+};
+
+/*
+ * A pidlist is a list of pids that virtually represents the contents of one
+ * of the cgroup files ("procs" or "tasks"). We keep a list of such pidlists,
+ * a pair (one each for procs, tasks) for each pid namespace that's relevant
+ * to the cgroup.
+ */
struct cgroup_pidlist {
- /* protects the other fields */
- struct rw_semaphore mutex;
+ /*
+ * used to find which pidlist is wanted. doesn't change as long as
+ * this particular list stays in the list.
+ */
+ struct { enum cgroup_filetype type; struct pid_namespace *ns; } key;
/* array of xids */
pid_t *list;
/* how many elements the above list has */
int length;
/* how many files are using the current array */
int use_count;
+ /* each of these stored in a list by its cgroup */
+ struct list_head links;
+ /* pointer to the cgroup we belong to, for list removal purposes */
+ struct cgroup *owner;
+ /* protects the other fields */
+ struct rw_semaphore mutex;
};
struct cgroup {
@@ -190,9 +211,12 @@ struct cgroup {
*/
struct list_head release_list;
- /* we will have two separate pidlists, one for pids (the tasks file)
- * and one for tgids (the procs file). */
- struct cgroup_pidlist tasks, procs;
+ /*
+ * list of pidlists, up to two for each namespace (one for procs, one
+ * for tasks); created on demand.
+ */
+ struct list_head pidlists;
+ struct mutex pidlist_mutex;
/* For RCU-protected deletion */
struct rcu_head rcu_head;