[PATCH 3/8] cgroups: Add previous cgroup in can_attach_task/attach_task callbacks

Frederic Weisbecker
2011-07-29T16:14:53Z

This is to prepare the integration of a new max number of proc
cgroup subsystem. We'll need to release some resources from the
previous cgroup.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Aditya Kali <adityakali@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
---
block/blk-cgroup.c | 10 ++++++----
include/linux/cgroup.h | 5 +++--
kernel/cgroup.c | 10 ++++++----
kernel/cgroup_freezer.c | 3 ++-
kernel/cpuset.c | 6 ++++--
kernel/events/core.c | 5 +++--
kernel/sched.c | 6 ++++--
7 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index bcaf16e..d1bfe88 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -30,8 +30,8 @@ EXPORT_SYMBOL_GPL(blkio_root_cgroup);

static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *,
struct cgroup *);
-static int blkiocg_can_attach_task(struct cgroup *, struct task_struct *);
-static void blkiocg_attach_task(struct cgroup *, struct task_struct *);
+static int blkiocg_can_attach_task(struct cgroup *, struct cgroup *, struct task_struct *);
+static void blkiocg_attach_task(struct cgroup *, struct cgroup *, struct task_struct *);
static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *);
static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *);

@@ -1614,7 +1614,8 @@ done:
* of the main cic data structures. For now we allow a task to change
* its cgroup only if it's the only owner of its ioc.
*/
-static int blkiocg_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
+static int blkiocg_can_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
+ struct task_struct *tsk)
{
struct io_context *ioc;
int ret = 0;
@@ -1629,7 +1630,8 @@ static int blkiocg_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
return ret;
}

-static void blkiocg_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
+static void blkiocg_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
+ struct task_struct *tsk)
{
struct io_context *ioc;

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index ab4ac0c..e8288a0 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -468,11 +468,12 @@ struct cgroup_subsys {
void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp);
int (*can_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct task_struct *tsk);
- int (*can_attach_task)(struct cgroup *cgrp, struct task_struct *tsk);
+ int (*can_attach_task)(struct cgroup *cgrp, struct cgroup *old_cgrp,
+ struct task_struct *tsk);
void (*cancel_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct task_struct *tsk);
void (*pre_attach)(struct cgroup *cgrp);
- void (*attach_task)(struct cgroup *cgrp, struct task_struct *tsk);
+ void (*attach_task)(struct cgroup *cgrp, struct cgroup *old_cgrp, struct task_struct *tsk);
void (*attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct cgroup *old_cgrp, struct task_struct *tsk);
void (*fork)(struct cgroup_subsys *ss, struct task_struct *task);
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2731d11..c3ee4cf 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1841,7 +1841,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
}
}
if (ss->can_attach_task) {
- retval = ss->can_attach_task(cgrp, tsk);
+ retval = ss->can_attach_task(cgrp, oldcgrp, tsk);
if (retval) {
failed_ss = ss;
goto out;
@@ -1857,7 +1857,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
if (ss->pre_attach)
ss->pre_attach(cgrp);
if (ss->attach_task)
- ss->attach_task(cgrp, tsk);
+ ss->attach_task(cgrp, oldcgrp, tsk);
if (ss->attach)
ss->attach(ss, cgrp, oldcgrp, tsk);
}
@@ -2072,7 +2072,9 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
/* run on each task in the threadgroup. */
for (i = 0; i < group_size; i++) {
tsk = flex_array_get_ptr(group, i);
- retval = ss->can_attach_task(cgrp, tsk);
+ oldcgrp = task_cgroup_from_root(tsk, root);
+
+ retval = ss->can_attach_task(cgrp, oldcgrp, tsk);
if (retval) {
failed_ss = ss;
cancel_failed_ss = true;
@@ -2135,7 +2137,7 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
/* attach each task to each subsystem */
for_each_subsys(root, ss) {
if (ss->attach_task)
- ss->attach_task(cgrp, tsk);
+ ss->attach_task(cgrp, oldcgrp, tsk);
}
/* if the thread is PF_EXITING, it can just get skipped. */
retval = cgroup_task_migrate(cgrp, oldcgrp, tsk, true);
diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index e691818..c1421a1 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -175,7 +175,8 @@ static int freezer_can_attach(struct cgroup_subsys *ss,
return 0;
}

-static int freezer_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
+static int freezer_can_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
+ struct task_struct *tsk)
{
rcu_read_lock();
if (__cgroup_freezing_or_frozen(tsk)) {
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 9c9b754..f66c9b4 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1390,7 +1390,8 @@ static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cont,
return 0;
}

-static int cpuset_can_attach_task(struct cgroup *cgrp, struct task_struct *task)
+static int cpuset_can_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
+ struct task_struct *task)
{
return security_task_setscheduler(task);
}
@@ -1418,7 +1419,8 @@ static void cpuset_pre_attach(struct cgroup *cont)
}

/* Per-thread attachment work. */
-static void cpuset_attach_task(struct cgroup *cont, struct task_struct *tsk)
+static void cpuset_attach_task(struct cgroup *cont, struct cgroup *old,
+ struct task_struct *tsk)
{
int err;
struct cpuset *cs = cgroup_cs(cont);
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 9efe710..3daf0eb 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7403,7 +7403,8 @@ static int __perf_cgroup_move(void *info)
}

static void
-perf_cgroup_attach_task(struct cgroup *cgrp, struct task_struct *task)
+perf_cgroup_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
+ struct task_struct *task)
{
task_function_call(task, __perf_cgroup_move, task);
}
@@ -7419,7 +7420,7 @@ static void perf_cgroup_exit(struct cgroup_subsys *ss, struct cgroup *cgrp,
if (!(task->flags & PF_EXITING))
return;

- perf_cgroup_attach_task(cgrp, task);
+ perf_cgroup_attach_task(cgrp, old_cgrp, task);
}

struct cgroup_subsys perf_subsys = {
diff --git a/kernel/sched.c b/kernel/sched.c
index fde6ff9..cbe0556 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -8943,7 +8943,8 @@ cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
}

static int
-cpu_cgroup_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
+cpu_cgroup_can_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
+ struct task_struct *tsk)
{
#ifdef CONFIG_RT_GROUP_SCHED
if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
@@ -8957,7 +8958,8 @@ cpu_cgroup_can_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
}

static void
-cpu_cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
+cpu_cgroup_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
+ struct task_struct *tsk)
{
sched_move_task(tsk);
}
--
1.7.5.4