summaryrefslogtreecommitdiff
path: root/include/linux/cgroup.h
diff options
context:
space:
mode:
authorTejun Heo <tj@kernel.org>2017-05-15 09:34:01 -0400
committerTejun Heo <tj@kernel.org>2017-07-21 11:14:51 -0400
commitbc2fb7ed089ffd16d26e1d95b898a37d2b37d201 (patch)
tree87675b436609b0a31ffde08798c761876e6c4db0 /include/linux/cgroup.h
parent715c809d9a9e38d8fb9476757ddaf64c1a9f767f (diff)
cgroup: add @flags to css_task_iter_start() and implement CSS_TASK_ITER_PROCS
css_task_iter currently always walks all tasks. With the scheduled cgroup v2 thread support, the iterator would need to handle multiple types of iteration. As a preparation, add @flags to css_task_iter_start() and implement CSS_TASK_ITER_PROCS. If the flag is not specified, it walks all tasks as before. When asserted, the iterator only walks the group leaders. For now, the only user of the flag is cgroup v2 "cgroup.procs" file which no longer needs to skip non-leader tasks in cgroup_procs_next(). Note that cgroup v1 "cgroup.procs" can't use the group leader walk as v1 "cgroup.procs" doesn't mean "list all thread group leaders in the cgroup" but "list all thread group id's with any threads in the cgroup". While at it, update cgroup_procs_show() to use task_pid_vnr() instead of task_tgid_vnr(). As the iteration guarantees that the function only sees group leaders, this doesn't change the output and will allow sharing the function for thread iteration. Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'include/linux/cgroup.h')
-rw-r--r--include/linux/cgroup.h6
1 files changed, 5 insertions, 1 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 308b10797a54..cae5831ae650 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -36,9 +36,13 @@
#define CGROUP_WEIGHT_DFL 100
#define CGROUP_WEIGHT_MAX 10000
+/* walk only threadgroup leaders */
+#define CSS_TASK_ITER_PROCS (1U << 0)
+
/* a css_task_iter should be treated as an opaque object */
struct css_task_iter {
struct cgroup_subsys *ss;
+ unsigned int flags;
struct list_head *cset_pos;
struct list_head *cset_head;
@@ -129,7 +133,7 @@ struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset,
struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset,
struct cgroup_subsys_state **dst_cssp);
-void css_task_iter_start(struct cgroup_subsys_state *css,
+void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags,
struct css_task_iter *it);
struct task_struct *css_task_iter_next(struct css_task_iter *it);
void css_task_iter_end(struct css_task_iter *it);