Move cgroup list to proper shared storage

Otherwise we have per-job lists, and that doesn't help very much
with cleaning up.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/cgroup.h b/cgroup.h
index 1c67ba8..b246ef8 100644
--- a/cgroup.h
+++ b/cgroup.h
@@ -3,14 +3,14 @@
 
 #ifdef FIO_HAVE_CGROUPS
 
-int cgroup_setup(struct thread_data *td);
+int cgroup_setup(struct thread_data *td, struct flist_head *list);
 void cgroup_shutdown(struct thread_data *td);
 
-void cgroup_kill(void);
+void cgroup_kill(struct flist_head *list);
 
 #else
 
-static inline int cgroup_setup(struct thread_data *td)
+static inline int cgroup_setup(struct thread_data *td, struct flist_head *list);
 {
 	td_verror(td, EINVAL, "cgroup_setup");
 	return 1;
@@ -20,7 +20,7 @@
 {
 }
 
-void cgroup_kill(void)
+void cgroup_kill(struct flist_head *list);
 {
 }