diff options
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 146 |
1 files changed, 143 insertions, 3 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index cc68fe68a60e..db245f19eb8a 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -33,6 +33,7 @@ #include <linux/mutex.h> #include <linux/mount.h> #include <linux/pagemap.h> +#include <linux/proc_fs.h> #include <linux/rcupdate.h> #include <linux/sched.h> #include <linux/seq_file.h> @@ -247,13 +248,15 @@ static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, int mode); static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry); static int cgroup_populate_dir(struct cgroup *cont); static struct inode_operations cgroup_dir_inode_operations; +static struct file_operations proc_cgroupstats_operations; + +static struct backing_dev_info cgroup_backing_dev_info = { + .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, +}; static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb) { struct inode *inode = new_inode(sb); - static struct backing_dev_info cgroup_backing_dev_info = { - .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, - }; if (inode) { inode->i_mode = mode; @@ -1600,6 +1603,11 @@ int __init cgroup_init(void) { int err; int i; + struct proc_dir_entry *entry; + + err = bdi_init(&cgroup_backing_dev_info); + if (err) + return err; for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; @@ -1611,10 +1619,142 @@ int __init cgroup_init(void) if (err < 0) goto out; + entry = create_proc_entry("cgroups", 0, NULL); + if (entry) + entry->proc_fops = &proc_cgroupstats_operations; + out: + if (err) + bdi_destroy(&cgroup_backing_dev_info); + return err; } +/* + * proc_cgroup_show() + * - Print task's cgroup paths into seq_file, one line for each hierarchy + * - Used for /proc/<pid>/cgroup. + * - No need to task_lock(tsk) on this tsk->cgroup reference, as it + * doesn't really matter if tsk->cgroup changes after we read it, + * and we take cgroup_mutex, keeping attach_task() from changing it + * anyway. No need to check that tsk->cgroup != NULL, thanks to + * the_top_cgroup_hack in cgroup_exit(), which sets an exiting tasks + * cgroup to top_cgroup. + */ + +/* TODO: Use a proper seq_file iterator */ +static int proc_cgroup_show(struct seq_file *m, void *v) +{ + struct pid *pid; + struct task_struct *tsk; + char *buf; + int retval; + struct cgroupfs_root *root; + + retval = -ENOMEM; + buf = kmalloc(PAGE_SIZE, GFP_KERNEL); + if (!buf) + goto out; + + retval = -ESRCH; + pid = m->private; + tsk = get_pid_task(pid, PIDTYPE_PID); + if (!tsk) + goto out_free; + + retval = 0; + + mutex_lock(&cgroup_mutex); + + for_each_root(root) { + struct cgroup_subsys *ss; + struct cgroup *cont; + int subsys_id; + int count = 0; + + /* Skip this hierarchy if it has no active subsystems */ + if (!root->actual_subsys_bits) + continue; + for_each_subsys(root, ss) + seq_printf(m, "%s%s", count++ ? "," : "", ss->name); + seq_putc(m, ':'); + get_first_subsys(&root->top_cgroup, NULL, &subsys_id); + cont = task_cgroup(tsk, subsys_id); + retval = cgroup_path(cont, buf, PAGE_SIZE); + if (retval < 0) + goto out_unlock; + seq_puts(m, buf); + seq_putc(m, '\n'); + } + +out_unlock: + mutex_unlock(&cgroup_mutex); + put_task_struct(tsk); +out_free: + kfree(buf); +out: + return retval; +} + +static int cgroup_open(struct inode *inode, struct file *file) +{ + struct pid *pid = PROC_I(inode)->pid; + return single_open(file, proc_cgroup_show, pid); +} + +struct file_operations proc_cgroup_operations = { + .open = cgroup_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +/* Display information about each subsystem and each hierarchy */ +static int proc_cgroupstats_show(struct seq_file *m, void *v) +{ + int i; + struct cgroupfs_root *root; + + mutex_lock(&cgroup_mutex); + seq_puts(m, "Hierarchies:\n"); + for_each_root(root) { + struct cgroup_subsys *ss; + int first = 1; + seq_printf(m, "%p: bits=%lx cgroups=%d (", root, + root->subsys_bits, root->number_of_cgroups); + for_each_subsys(root, ss) { + seq_printf(m, "%s%s", first ? "" : ", ", ss->name); + first = false; + } + seq_putc(m, ')'); + if (root->sb) { + seq_printf(m, " s_active=%d", + atomic_read(&root->sb->s_active)); + } + seq_putc(m, '\n'); + } + seq_puts(m, "Subsystems:\n"); + for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { + struct cgroup_subsys *ss = subsys[i]; + seq_printf(m, "%d: name=%s hierarchy=%p\n", + i, ss->name, ss->root); + } + mutex_unlock(&cgroup_mutex); + return 0; +} + +static int cgroupstats_open(struct inode *inode, struct file *file) +{ + return single_open(file, proc_cgroupstats_show, 0); +} + +static struct file_operations proc_cgroupstats_operations = { + .open = cgroupstats_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + /** * cgroup_fork - attach newly forked task to its parents cgroup. * @tsk: pointer to task_struct of forking parent process. |