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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2011-02-07 17:02:20 +0100
committerIngo Molnar <mingo@elte.hu>2011-02-16 13:30:47 +0100
commitd41d5a01631af821d3a3447e6613a316f5ee6c25 (patch)
tree405ab6bc24e06a64dc17ccafb6daead1400cb29e
parentb00560f2d4de69bb12f66f9605985b516df98d77 (diff)
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>
-rw-r--r--include/linux/cgroup.h3
-rw-r--r--kernel/cgroup.c31
-rw-r--r--kernel/sched.c6
3 files changed, 22 insertions, 18 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index ce104e33cd2..38117d93733 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -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);
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index b24d7027b83..f6495f33a35 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -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);
}
diff --git a/kernel/sched.c b/kernel/sched.c
index e142e92f38d..79e611cd83d 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -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.