cgroup: introduce cgroup_taskset and use it in subsys->can_attach(), cancel_attach() and attach()
Currently, there's no way to pass multiple tasks to cgroup_subsys
methods necessitating the need for separate per-process and per-task
methods. This patch introduces cgroup_taskset which can be used to
pass multiple tasks and their associated cgroups to cgroup_subsys
methods.
Three methods - can_attach(), cancel_attach() and attach() - are
converted to use cgroup_taskset. This unifies passed parameters so
that all methods have access to all information. Conversions in this
patchset are identical and don't introduce any behavior change.
-v2: documentation updated as per Paul Menage's suggestion.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul Menage <paul@paulmenage.org>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: James Morris <jmorris@namei.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 6aff93c..81640e7 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5298,8 +5298,9 @@
static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
struct cgroup *cgroup,
- struct task_struct *p)
+ struct cgroup_taskset *tset)
{
+ struct task_struct *p = cgroup_taskset_first(tset);
int ret = 0;
struct mem_cgroup *memcg = mem_cgroup_from_cont(cgroup);
@@ -5337,7 +5338,7 @@
static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
struct cgroup *cgroup,
- struct task_struct *p)
+ struct cgroup_taskset *tset)
{
mem_cgroup_clear_mc();
}
@@ -5454,9 +5455,9 @@
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
struct cgroup *cont,
- struct cgroup *old_cont,
- struct task_struct *p)
+ struct cgroup_taskset *tset)
{
+ struct task_struct *p = cgroup_taskset_first(tset);
struct mm_struct *mm = get_task_mm(p);
if (mm) {
@@ -5471,19 +5472,18 @@
#else /* !CONFIG_MMU */
static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
struct cgroup *cgroup,
- struct task_struct *p)
+ struct cgroup_taskset *tset)
{
return 0;
}
static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
struct cgroup *cgroup,
- struct task_struct *p)
+ struct cgroup_taskset *tset)
{
}
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
struct cgroup *cont,
- struct cgroup *old_cont,
- struct task_struct *p)
+ struct cgroup_taskset *tset)
{
}
#endif