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authorLinus Torvalds <torvalds@linux-foundation.org>2015-09-02 08:04:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-09-02 08:04:23 -0700
commit8bdc69b764013a9b5ebeef7df8f314f1066c5d79 (patch)
tree335dcb29c9ba06142917121d551575d360eca63e /kernel/cgroup.c
parent76ec51ef5edfe540bbc3c61b860f88deb8e6a37b (diff)
parent20f1f4b5ffb870631bf4a4e7c7ba10e3528ae6a6 (diff)
downloadop-kernel-dev-8bdc69b764013a9b5ebeef7df8f314f1066c5d79.zip
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Merge branch 'for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo: - a new PIDs controller is added. It turns out that PIDs are actually an independent resource from kmem due to the limited PID space. - more core preparations for the v2 interface. Once cpu side interface is settled, it should be ready for lifting the devel mask. for-4.3-unified-base was temporarily branched so that other trees (block) can pull cgroup core changes that blkcg changes depend on. - a non-critical idr_preload usage bug fix. * 'for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: pids: fix invalid get/put usage cgroup: introduce cgroup_subsys->legacy_name cgroup: don't print subsystems for the default hierarchy cgroup: make cftype->private a unsigned long cgroup: export cgrp_dfl_root cgroup: define controller file conventions cgroup: fix idr_preload usage cgroup: add documentation for the PIDs controller cgroup: implement the PIDs subsystem cgroup: allow a cgroup subsystem to reject a fork
Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r--kernel/cgroup.c122
1 files changed, 101 insertions, 21 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index b89f316..f3f5cd5 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -145,6 +145,7 @@ static const char *cgroup_subsys_name[] = {
* part of that cgroup.
*/
struct cgroup_root cgrp_dfl_root;
+EXPORT_SYMBOL_GPL(cgrp_dfl_root);
/*
* The default hierarchy always exists but is hidden until mounted for the
@@ -186,6 +187,9 @@ static u64 css_serial_nr_next = 1;
static unsigned long have_fork_callback __read_mostly;
static unsigned long have_exit_callback __read_mostly;
+/* Ditto for the can_fork callback. */
+static unsigned long have_canfork_callback __read_mostly;
+
static struct cftype cgroup_dfl_base_files[];
static struct cftype cgroup_legacy_base_files[];
@@ -207,7 +211,7 @@ static int cgroup_idr_alloc(struct idr *idr, void *ptr, int start, int end,
idr_preload(gfp_mask);
spin_lock_bh(&cgroup_idr_lock);
- ret = idr_alloc(idr, ptr, start, end, gfp_mask);
+ ret = idr_alloc(idr, ptr, start, end, gfp_mask & ~__GFP_WAIT);
spin_unlock_bh(&cgroup_idr_lock);
idr_preload_end();
return ret;
@@ -1027,10 +1031,13 @@ static const struct file_operations proc_cgroupstats_operations;
static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft,
char *buf)
{
+ struct cgroup_subsys *ss = cft->ss;
+
if (cft->ss && !(cft->flags & CFTYPE_NO_PREFIX) &&
!(cgrp->root->flags & CGRP_ROOT_NOPREFIX))
snprintf(buf, CGROUP_FILE_NAME_MAX, "%s.%s",
- cft->ss->name, cft->name);
+ cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name,
+ cft->name);
else
strncpy(buf, cft->name, CGROUP_FILE_NAME_MAX);
return buf;
@@ -1332,9 +1339,10 @@ static int cgroup_show_options(struct seq_file *seq,
struct cgroup_subsys *ss;
int ssid;
- for_each_subsys(ss, ssid)
- if (root->subsys_mask & (1 << ssid))
- seq_printf(seq, ",%s", ss->name);
+ if (root != &cgrp_dfl_root)
+ for_each_subsys(ss, ssid)
+ if (root->subsys_mask & (1 << ssid))
+ seq_printf(seq, ",%s", ss->legacy_name);
if (root->flags & CGRP_ROOT_NOPREFIX)
seq_puts(seq, ",noprefix");
if (root->flags & CGRP_ROOT_XATTR)
@@ -1447,7 +1455,7 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
}
for_each_subsys(ss, i) {
- if (strcmp(token, ss->name))
+ if (strcmp(token, ss->legacy_name))
continue;
if (ss->disabled)
continue;
@@ -1666,7 +1674,7 @@ static int cgroup_setup_root(struct cgroup_root *root, unsigned long ss_mask)
lockdep_assert_held(&cgroup_mutex);
- ret = cgroup_idr_alloc(&root->cgroup_idr, root_cgrp, 1, 2, GFP_NOWAIT);
+ ret = cgroup_idr_alloc(&root->cgroup_idr, root_cgrp, 1, 2, GFP_KERNEL);
if (ret < 0)
goto out;
root_cgrp->id = ret;
@@ -4579,7 +4587,7 @@ static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss,
if (err)
goto err_free_css;
- err = cgroup_idr_alloc(&ss->css_idr, NULL, 2, 0, GFP_NOWAIT);
+ err = cgroup_idr_alloc(&ss->css_idr, NULL, 2, 0, GFP_KERNEL);
if (err < 0)
goto err_free_percpu_ref;
css->id = err;
@@ -4656,7 +4664,7 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
* Temporarily set the pointer to NULL, so idr_find() won't return
* a half-baked cgroup.
*/
- cgrp->id = cgroup_idr_alloc(&root->cgroup_idr, NULL, 2, 0, GFP_NOWAIT);
+ cgrp->id = cgroup_idr_alloc(&root->cgroup_idr, NULL, 2, 0, GFP_KERNEL);
if (cgrp->id < 0) {
ret = -ENOMEM;
goto out_cancel_ref;
@@ -4955,6 +4963,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early)
have_fork_callback |= (bool)ss->fork << ss->id;
have_exit_callback |= (bool)ss->exit << ss->id;
+ have_canfork_callback |= (bool)ss->can_fork << ss->id;
/* At system boot, before all subsystems have been
* registered, no tasks have been forked, so we don't
@@ -4993,6 +5002,8 @@ int __init cgroup_init_early(void)
ss->id = i;
ss->name = cgroup_subsys_name[i];
+ if (!ss->legacy_name)
+ ss->legacy_name = cgroup_subsys_name[i];
if (ss->early_init)
cgroup_init_subsys(ss, true);
@@ -5136,9 +5147,11 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
continue;
seq_printf(m, "%d:", root->hierarchy_id);
- for_each_subsys(ss, ssid)
- if (root->subsys_mask & (1 << ssid))
- seq_printf(m, "%s%s", count++ ? "," : "", ss->name);
+ if (root != &cgrp_dfl_root)
+ for_each_subsys(ss, ssid)
+ if (root->subsys_mask & (1 << ssid))
+ seq_printf(m, "%s%s", count++ ? "," : "",
+ ss->legacy_name);
if (strlen(root->name))
seq_printf(m, "%sname=%s", count ? "," : "",
root->name);
@@ -5178,7 +5191,7 @@ static int proc_cgroupstats_show(struct seq_file *m, void *v)
for_each_subsys(ss, i)
seq_printf(m, "%s\t%d\t%d\t%d\n",
- ss->name, ss->root->hierarchy_id,
+ ss->legacy_name, ss->root->hierarchy_id,
atomic_read(&ss->root->nr_cgrps), !ss->disabled);
mutex_unlock(&cgroup_mutex);
@@ -5197,6 +5210,19 @@ static const struct file_operations proc_cgroupstats_operations = {
.release = single_release,
};
+static void **subsys_canfork_priv_p(void *ss_priv[CGROUP_CANFORK_COUNT], int i)
+{
+ if (CGROUP_CANFORK_START <= i && i < CGROUP_CANFORK_END)
+ return &ss_priv[i - CGROUP_CANFORK_START];
+ return NULL;
+}
+
+static void *subsys_canfork_priv(void *ss_priv[CGROUP_CANFORK_COUNT], int i)
+{
+ void **private = subsys_canfork_priv_p(ss_priv, i);
+ return private ? *private : NULL;
+}
+
/**
* cgroup_fork - initialize cgroup related fields during copy_process()
* @child: pointer to task_struct of forking parent process.
@@ -5212,6 +5238,57 @@ void cgroup_fork(struct task_struct *child)
}
/**
+ * cgroup_can_fork - called on a new task before the process is exposed
+ * @child: the task in question.
+ *
+ * This calls the subsystem can_fork() callbacks. If the can_fork() callback
+ * returns an error, the fork aborts with that error code. This allows for
+ * a cgroup subsystem to conditionally allow or deny new forks.
+ */
+int cgroup_can_fork(struct task_struct *child,
+ void *ss_priv[CGROUP_CANFORK_COUNT])
+{
+ struct cgroup_subsys *ss;
+ int i, j, ret;
+
+ for_each_subsys_which(ss, i, &have_canfork_callback) {
+ ret = ss->can_fork(child, subsys_canfork_priv_p(ss_priv, i));
+ if (ret)
+ goto out_revert;
+ }
+
+ return 0;
+
+out_revert:
+ for_each_subsys(ss, j) {
+ if (j >= i)
+ break;
+ if (ss->cancel_fork)
+ ss->cancel_fork(child, subsys_canfork_priv(ss_priv, j));
+ }
+
+ return ret;
+}
+
+/**
+ * cgroup_cancel_fork - called if a fork failed after cgroup_can_fork()
+ * @child: the task in question
+ *
+ * This calls the cancel_fork() callbacks if a fork failed *after*
+ * cgroup_can_fork() succeded.
+ */
+void cgroup_cancel_fork(struct task_struct *child,
+ void *ss_priv[CGROUP_CANFORK_COUNT])
+{
+ struct cgroup_subsys *ss;
+ int i;
+
+ for_each_subsys(ss, i)
+ if (ss->cancel_fork)
+ ss->cancel_fork(child, subsys_canfork_priv(ss_priv, i));
+}
+
+/**
* cgroup_post_fork - called on a new task after adding it to the task list
* @child: the task in question
*
@@ -5221,7 +5298,8 @@ void cgroup_fork(struct task_struct *child)
* cgroup_task_iter_start() - to guarantee that the new task ends up on its
* list.
*/
-void cgroup_post_fork(struct task_struct *child)
+void cgroup_post_fork(struct task_struct *child,
+ void *old_ss_priv[CGROUP_CANFORK_COUNT])
{
struct cgroup_subsys *ss;
int i;
@@ -5266,7 +5344,7 @@ void cgroup_post_fork(struct task_struct *child)
* and addition to css_set.
*/
for_each_subsys_which(ss, i, &have_fork_callback)
- ss->fork(child);
+ ss->fork(child, subsys_canfork_priv(old_ss_priv, i));
}
/**
@@ -5400,12 +5478,14 @@ static int __init cgroup_disable(char *str)
continue;
for_each_subsys(ss, i) {
- if (!strcmp(token, ss->name)) {
- ss->disabled = 1;
- printk(KERN_INFO "Disabling %s control group"
- " subsystem\n", ss->name);
- break;
- }
+ if (strcmp(token, ss->name) &&
+ strcmp(token, ss->legacy_name))
+ continue;
+
+ ss->disabled = 1;
+ printk(KERN_INFO "Disabling %s control group subsystem\n",
+ ss->name);
+ break;
}
}
return 1;
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