cgroup: Fix cgroup_subsys::exit callback

Make the ::exit method act like ::attach, it is after all very nearly
the same thing.

The bug had no effect on correctness - fixing it is an optimization for
the scheduler. Also, later perf-cgroups patches rely on it.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Menage <menage@google.com>
LKML-Reference: <1297160655.13327.92.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2011-02-07 17:02:20 +01:00 committed by Ingo Molnar
parent b00560f2d4
commit d41d5a0163
3 changed files with 22 additions and 18 deletions

View File

@ -474,7 +474,8 @@ struct cgroup_subsys {
struct cgroup *old_cgrp, struct task_struct *tsk,
bool threadgroup);
void (*fork)(struct cgroup_subsys *ss, struct task_struct *task);
void (*exit)(struct cgroup_subsys *ss, struct task_struct *task);
void (*exit)(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct cgroup *old_cgrp, struct task_struct *task);
int (*populate)(struct cgroup_subsys *ss,
struct cgroup *cgrp);
void (*post_clone)(struct cgroup_subsys *ss, struct cgroup *cgrp);

View File

@ -4230,20 +4230,8 @@ void cgroup_post_fork(struct task_struct *child)
*/
void cgroup_exit(struct task_struct *tsk, int run_callbacks)
{
int i;
struct css_set *cg;
if (run_callbacks && need_forkexit_callback) {
/*
* modular subsystems can't use callbacks, so no need to lock
* the subsys array
*/
for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
if (ss->exit)
ss->exit(ss, tsk);
}
}
int i;
/*
* Unlink from the css_set task list if necessary.
@ -4261,7 +4249,24 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks)
task_lock(tsk);
cg = tsk->cgroups;
tsk->cgroups = &init_css_set;
if (run_callbacks && need_forkexit_callback) {
/*
* modular subsystems can't use callbacks, so no need to lock
* the subsys array
*/
for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
if (ss->exit) {
struct cgroup *old_cgrp =
rcu_dereference_raw(cg->subsys[i])->cgroup;
struct cgroup *cgrp = task_cgroup(tsk, i);
ss->exit(ss, cgrp, old_cgrp, tsk);
}
}
}
task_unlock(tsk);
if (cg)
put_css_set_taskexit(cg);
}

View File

@ -606,9 +606,6 @@ static inline struct task_group *task_group(struct task_struct *p)
struct task_group *tg;
struct cgroup_subsys_state *css;
if (p->flags & PF_EXITING)
return &root_task_group;
css = task_subsys_state_check(p, cpu_cgroup_subsys_id,
lockdep_is_held(&task_rq(p)->lock));
tg = container_of(css, struct task_group, css);
@ -8863,7 +8860,8 @@ cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
}
static void
cpu_cgroup_exit(struct cgroup_subsys *ss, struct task_struct *task)
cpu_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct cgroup *old_cgrp, struct task_struct *task)
{
/*
* cgroup_exit() is called in the copy_process() failure path.