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

fs/proc/base.c

+7 −0
Original line number Diff line number Diff line
@@ -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),

include/linux/cgroup.h

+2 −0
Original line number Diff line number Diff line
@@ -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

kernel/cgroup.c

+143 −3
Original line number Diff line number Diff line
@@ -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>
@@ -247,14 +248,16 @@ 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 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,

};



static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb)

{

	struct inode *inode = new_inode(sb);



	if (inode) {

		inode->i_mode = mode;

		inode->i_uid = current->fsuid;
@@ -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.