From: Frederic Weisbecker <fweisbec@gmail.com>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Paul Menage <paul@paulmenage.org>, Li Zefan <lizf@cn.fujitsu.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Aditya Kali <adityakali@google.com>,
Oleg Nesterov <oleg@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Kay Sievers <kay.sievers@vrfy.org>,
Tim Hockin <thockin@hockin.org>, Tejun Heo <tj@kernel.org>
Subject: [RFC PATCH 11/12] cgroups: Allow subsystems to cancel a fork
Date: Tue, 6 Sep 2011 02:13:05 +0200 [thread overview]
Message-ID: <1315267986-28937-12-git-send-email-fweisbec@gmail.com> (raw)
In-Reply-To: <1315267986-28937-1-git-send-email-fweisbec@gmail.com>
Let the subsystem's fork callback return an error value so
that they can cancel a fork. This is going to be used by
the task counter subsystem to implement the limit.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Menage <paul@paulmenage.org>
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>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Tim Hockin <thockin@hockin.org>
Cc: Tejun Heo <tj@kernel.org>
---
include/linux/cgroup.h | 14 +++++++++-----
kernel/cgroup.c | 23 +++++++++++++++++++----
kernel/cgroup_freezer.c | 6 ++++--
kernel/exit.c | 2 +-
kernel/fork.c | 7 +++++--
5 files changed, 38 insertions(+), 14 deletions(-)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 5e39341..253543b 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -32,9 +32,11 @@ extern int cgroup_lock_is_held(void);
extern bool cgroup_lock_live_group(struct cgroup *cgrp);
extern void cgroup_unlock(void);
extern void cgroup_fork(struct task_struct *p);
-extern void cgroup_fork_callbacks(struct task_struct *p);
+extern int cgroup_fork_callbacks(struct task_struct *p,
+ struct cgroup_subsys **failed_ss);
extern void cgroup_post_fork(struct task_struct *p);
-extern void cgroup_exit(struct task_struct *p, int run_callbacks);
+extern void cgroup_exit(struct task_struct *p, int run_callbacks,
+ struct cgroup_subsys *failed_ss);
extern int cgroupstats_build(struct cgroupstats *stats,
struct dentry *dentry);
extern int cgroup_load_subsys(struct cgroup_subsys *ss);
@@ -477,7 +479,7 @@ struct cgroup_subsys {
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);
+ int (*fork)(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,
@@ -634,9 +636,11 @@ struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id);
static inline int cgroup_init_early(void) { return 0; }
static inline int cgroup_init(void) { return 0; }
static inline void cgroup_fork(struct task_struct *p) {}
-static inline void cgroup_fork_callbacks(struct task_struct *p) {}
+static inline int cgroup_fork_callbacks(struct task_struct *p,
+ struct cgroup_subsys **failed_ss) {}
static inline void cgroup_post_fork(struct task_struct *p) {}
-static inline void cgroup_exit(struct task_struct *p, int callbacks) {}
+static inline void cgroup_exit(struct task_struct *p, int callbacks,
+ struct cgroup_subsys **failed_ss) {}
static inline void cgroup_lock(void) {}
static inline void cgroup_unlock(void) {}
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 73ee2fd..c99e9cc 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4538,8 +4538,11 @@ void cgroup_fork(struct task_struct *child)
* tasklist. No need to take any locks since no-one can
* be operating on this task.
*/
-void cgroup_fork_callbacks(struct task_struct *child)
+int cgroup_fork_callbacks(struct task_struct *child,
+ struct cgroup_subsys **failed_ss)
{
+ int err;
+
if (need_forkexit_callback) {
int i;
/*
@@ -4549,10 +4552,17 @@ void cgroup_fork_callbacks(struct task_struct *child)
*/
for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
- if (ss->fork)
- ss->fork(ss, child);
+ if (ss->fork) {
+ err = ss->fork(ss, child);
+ if (err) {
+ *failed_ss = ss;
+ return err;
+ }
+ }
}
}
+
+ return 0;
}
/**
@@ -4610,7 +4620,8 @@ void cgroup_post_fork(struct task_struct *child)
* which wards off any cgroup_attach_task() attempts, or task is a failed
* fork, never visible to cgroup_attach_task.
*/
-void cgroup_exit(struct task_struct *tsk, int run_callbacks)
+void cgroup_exit(struct task_struct *tsk, int run_callbacks,
+ struct cgroup_subsys *failed_ss)
{
struct css_set *cg;
int i;
@@ -4639,6 +4650,10 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks)
*/
for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
+
+ if (ss == failed_ss)
+ break;
+
if (ss->exit) {
struct cgroup *old_cgrp =
rcu_dereference_raw(cg->subsys[i])->cgroup;
diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index c1421a1..30a4332 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -187,7 +187,7 @@ static int freezer_can_attach_task(struct cgroup *cgrp, struct cgroup *old_cgrp,
return 0;
}
-static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
+static int freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
{
struct freezer *freezer;
@@ -207,7 +207,7 @@ static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
* following check.
*/
if (!freezer->css.cgroup->parent)
- return;
+ return 0;
spin_lock_irq(&freezer->lock);
BUG_ON(freezer->state == CGROUP_FROZEN);
@@ -216,6 +216,8 @@ static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
if (freezer->state == CGROUP_FREEZING)
freeze_task(task, true);
spin_unlock_irq(&freezer->lock);
+
+ return 0;
}
/*
diff --git a/kernel/exit.c b/kernel/exit.c
index 2913b35..abab32b 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -994,7 +994,7 @@ NORET_TYPE void do_exit(long code)
*/
perf_event_exit_task(tsk);
- cgroup_exit(tsk, 1);
+ cgroup_exit(tsk, 1, NULL);
if (group_dead)
disassociate_ctty(1);
diff --git a/kernel/fork.c b/kernel/fork.c
index f716436..989c5a0 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1058,6 +1058,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
int retval;
struct task_struct *p;
int cgroup_callbacks_done = 0;
+ struct cgroup_subsys *cgroup_failed_ss = NULL;
if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
return ERR_PTR(-EINVAL);
@@ -1316,8 +1317,10 @@ static struct task_struct *copy_process(unsigned long clone_flags,
/* Now that the task is set up, run cgroup callbacks if
* necessary. We need to run them before the task is visible
* on the tasklist. */
- cgroup_fork_callbacks(p);
+ retval = cgroup_fork_callbacks(p, &cgroup_failed_ss);
cgroup_callbacks_done = 1;
+ if (retval)
+ goto bad_fork_free_pid;
/* Need tasklist lock for parent etc handling! */
write_lock_irq(&tasklist_lock);
@@ -1423,7 +1426,7 @@ bad_fork_cleanup_cgroup:
#endif
if (clone_flags & CLONE_THREAD)
threadgroup_fork_read_unlock(current);
- cgroup_exit(p, cgroup_callbacks_done);
+ cgroup_exit(p, cgroup_callbacks_done, cgroup_failed_ss);
delayacct_tsk_free(p);
module_put(task_thread_info(p)->exec_domain->module);
bad_fork_cleanup_count:
--
1.7.5.4
next prev parent reply other threads:[~2011-09-06 0:14 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-06 0:12 [PATCH 00/12 v4][RESEND] cgroups: Task counter subsystem Frederic Weisbecker
2011-09-06 0:12 ` [PATCH 01/12] cgroups: Add res_counter_write_u64() API Frederic Weisbecker
2011-09-06 0:12 ` [PATCH 02/12] cgroups: New resource counter inheritance API Frederic Weisbecker
2011-09-06 22:17 ` Andrew Morton
2011-09-08 13:25 ` Frederic Weisbecker
2011-09-06 0:12 ` [PATCH 03/12] cgroups: Add previous cgroup in can_attach_task/attach_task callbacks Frederic Weisbecker
2011-09-06 0:12 ` [PATCH 04/12] cgroups: New cancel_attach_task subsystem callback Frederic Weisbecker
2011-09-06 0:12 ` [PATCH 05/12] cgroups: Ability to stop res charge propagation on bounded ancestor Frederic Weisbecker
2011-09-06 0:13 ` [PATCH 06/12] cgroups: Add res counter common ancestor searching Frederic Weisbecker
2011-09-06 22:21 ` Andrew Morton
2011-09-09 12:31 ` Frederic Weisbecker
2011-09-06 0:13 ` [PATCH 07/12] res_counter: Allow charge failure pointer to be null Frederic Weisbecker
2011-09-06 0:13 ` [PATCH 08/12] cgroups: Pull up res counter charge failure interpretation to caller Frederic Weisbecker
2011-09-06 22:26 ` Andrew Morton
2011-09-09 13:33 ` Frederic Weisbecker
2011-09-09 15:17 ` Andrew Morton
2011-09-06 0:13 ` [PATCH 09/12] cgroups: Add a task counter subsystem Frederic Weisbecker
2011-09-06 22:40 ` Andrew Morton
2011-09-13 15:13 ` Frederic Weisbecker
2011-09-06 0:13 ` [PATCH 10/12] cgroups: Add documentation for " Frederic Weisbecker
2011-09-06 22:41 ` Andrew Morton
2011-09-13 17:35 ` Frederic Weisbecker
2011-09-06 0:13 ` Frederic Weisbecker [this message]
2011-09-15 21:09 ` [RFC PATCH 11/12] cgroups: Allow subsystems to cancel a fork Andrew Morton
2011-10-01 15:29 ` Frederic Weisbecker
2011-09-06 0:13 ` [RFC PATCH 12/12] cgroups: Convert task counter to use the subsys fork callback Frederic Weisbecker
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