Commit a424316c authored by Paul Menage's avatar Paul Menage Committed by Linus Torvalds

Task Control Groups: add procfs interface

Add:

/proc/cgroups - general system info

/proc/*/cgroup - per-task cgroup membership info

[a.p.zijlstra@chello.nl: cgroups: bdi init hooks]
Signed-off-by: default avatarPaul Menage <menage@google.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 697f4161
......@@ -67,6 +67,7 @@
#include <linux/mount.h>
#include <linux/security.h>
#include <linux/ptrace.h>
#include <linux/cgroup.h>
#include <linux/cpuset.h>
#include <linux/audit.h>
#include <linux/poll.h>
......@@ -2132,6 +2133,9 @@ static const struct pid_entry tgid_base_stuff[] = {
#endif
#ifdef CONFIG_CPUSETS
REG("cpuset", S_IRUGO, cpuset),
#endif
#ifdef CONFIG_CGROUPS
REG("cgroup", S_IRUGO, cgroup),
#endif
INF("oom_score", S_IRUGO, oom_score),
REG("oom_adj", S_IRUGO|S_IWUSR, oom_adjust),
......@@ -2418,6 +2422,9 @@ static const struct pid_entry tid_base_stuff[] = {
#endif
#ifdef CONFIG_CPUSETS
REG("cpuset", S_IRUGO, cpuset),
#endif
#ifdef CONFIG_CGROUPS
REG("cgroup", S_IRUGO, cgroup),
#endif
INF("oom_score", S_IRUGO, oom_score),
REG("oom_adj", S_IRUGO|S_IWUSR, oom_adjust),
......
......@@ -29,6 +29,8 @@ extern void cgroup_fork(struct task_struct *p);
extern void cgroup_fork_callbacks(struct task_struct *p);
extern void cgroup_exit(struct task_struct *p, int run_callbacks);
extern struct file_operations proc_cgroup_operations;
/* Per-subsystem/per-cgroup state maintained by the system. */
struct cgroup_subsys_state {
/* The cgroup that this subsystem is attached to. Useful
......
......@@ -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.
......
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