[0/1] [patch -mm] Add containerstats (v3)

Balbir Singh
2007-06-08T18:14:41Z

Changelog (v3)

1. Use the container iterator (Paul Menage)
2. delayacct_set_flag() has now been moved to delayacct_blkio_start
(Andrew Morton)

Changelog (v2)

1. Instead of parsing long container path's use the dentry to match the
container for which stats are required. The user space application
opens the container directory and passes the file descriptor, which
is used to determine the container for which stats are required.
This approach was suggested by Paul Menage

This patch is inspired by the discussion at http://lkml.org/lkml/2007/4/11/187
and implements per container statistics as suggested by Andrew Morton
in http://lkml.org/lkml/2007/4/11/263. The patch is on top of 2.6.21-mm1
with Paul's containers v9 patches (forward ported)

This patch implements per container statistics infrastructure and re-uses
code from the taskstats interface. A new set of container operations are
registered with commands and attributes. It should be very easy to
*extend* per container statistics, by adding members to the containerstats
structure.

The current model for containerstats is a pull, a push model (to post
statistics on interesting events), should be very easy to add. Currently
user space requests for statistics by passing the container file descriptor.
Statistics about the state of all the tasks in the container is returned to
user space.

TODO's/NOTE:

This patch provides an infrastructure for implementing container statistics.
Based on the needs of each controller, we can incrementally add more statistics,
event based support for notification of statistics, accumulation of taskstats
into container statistics in the future.

Sample output

# ./containerstats -C /container/a
sleeping 2, blocked 0, running 1, stopped 0, uninterruptible 0

# ./containerstats -C /container/
sleeping 154, blocked 0, running 0, stopped 0, uninterruptible 0

If the approach looks good, I'll enhance and post the user space utility for
the same

Feedback, comments, test results are always welcome!

Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
---

Documentation/accounting/containerstats.txt | 27 ++++++++++
include/linux/Kbuild | 1
include/linux/container.h | 8 +++
include/linux/containerstats.h | 70 ++++++++++++++++++++++++++++
include/linux/delayacct.h | 13 +++++
kernel/container.c | 54 +++++++++++++++++++++
kernel/taskstats.c | 66 ++++++++++++++++++++++++++
7 files changed, 239 insertions(+)

diff -puN /dev/null Documentation/accounting/containerstats.txt
--- /dev/null 2007-06-01 20:42:04.000000000 +0530
+++ linux-2.6.22-rc24-mm2-balbir/Documentation/accounting/containerstats.txt 2007-06-08 23:11:03.000000000 +0530
@@ -0,0 +1,27 @@
+Containerstats is inspired by the discussion at
+http://lkml.org/lkml/2007/4/11/187 and implements per container statistics as
+suggested by Andrew Morton in http://lkml.org/lkml/2007/4/11/263.
+
+Per container statistics infrastructure re-uses code from the taskstats
+interface. A new set of container operations are registered with commands
+and attributes specific to containers. It should be very easy to
+extend per container statistics, by adding members to the containerstats
+structure.
+
+The current model for containerstats is a pull, a push model (to post
+statistics on interesting events), should be very easy to add. Currently
+user space requests for statistics by passing the container path.
+Statistics about the state of all the tasks in the container is returned to
+user space.
+
+NOTE: We currently rely on delay accounting for extracting information
+about tasks blocked on I/O. If CONFIG_TASK_DELAY_ACCT is disabled, this
+information will not be available.
+
+To extract container statistics a utility very similar to getdelays.c
+has been developed, the sample output of the utility is shown below
+
+~/balbir/containerstats # ./getdelays -C "/container/a"
+sleeping 1, blocked 0, running 1, stopped 0, uninterruptible 0
+~/balbir/containerstats # ./getdelays -C "/container"
+sleeping 155, blocked 0, running 1, stopped 0, uninterruptible 2
diff -puN include/linux/container.h~containers-taskstats include/linux/container.h
--- linux-2.6.22-rc24-mm2/include/linux/container.h~containers-taskstats 2007-06-08 23:11:03.000000000 +0530
+++ linux-2.6.22-rc24-mm2-balbir/include/linux/container.h 2007-06-08 23:11:25.000000000 +0530
@@ -13,6 +13,7 @@
#include <linux/cpumask.h>
#include <linux/nodemask.h>
#include <linux/rcupdate.h>
+#include <linux/containerstats.h>

#ifdef CONFIG_CONTAINERS

@@ -27,6 +28,8 @@ extern void container_unlock(void);
extern void container_fork(struct task_struct *p);
extern void container_fork_callbacks(struct task_struct *p);
extern void container_exit(struct task_struct *p, int run_callbacks);
+extern int containerstats_build(struct containerstats *stats,
+ struct dentry *dentry);

extern struct file_operations proc_container_operations;

@@ -288,6 +291,11 @@ static inline void container_exit(struct

static inline void container_lock(void) {}
static inline void container_unlock(void) {}
+static inline int containerstats_build(struct containerstats *stats,
+ struct dentry *dentry)
+{
+ return -EINVAL;
+}

#endif /* !CONFIG_CONTAINERS */

diff -puN /dev/null include/linux/containerstats.h
--- /dev/null 2007-06-01 20:42:04.000000000 +0530
+++ linux-2.6.22-rc24-mm2-balbir/include/linux/containerstats.h 2007-06-08 23:11:03.000000000 +0530
@@ -0,0 +1,70 @@
+/* containerstats.h - exporting per-container statistics
+ *
+ * Copyright IBM Corporation, 2007
+ * Author Balbir Singh <balbir@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#ifndef _LINUX_CONTAINERSTATS_H
+#define _LINUX_CONTAINERSTATS_H
+
+#include <linux/taskstats.h>
+
+/*
+ * Data shared between user space and kernel space on a per container
+ * basis. This data is shared using taskstats.
+ *
+ * Most of these states are derived by looking at the task->state value
+ * For the nr_io_wait state, a flag in the delay accounting structure
+ * indicates that the task is waiting on IO
+ *
+ * Each member is aligned to a 8 byte boundary.
+ */
+struct containerstats {
+ __u64 nr_sleeping; /* Number of tasks sleeping */
+ __u64 nr_running; /* Number of tasks running */
+ __u64 nr_stopped; /* Number of tasks in stopped state */
+ __u64 nr_uninterruptible; /* Number of tasks in uninterruptible */
+ /* state */
+ __u64 nr_io_wait; /* Number of tasks waiting on IO */
+};
+
+/*
+ * Commands sent from userspace
+ * Not versioned. New commands should only be inserted at the enum's end
+ * prior to __CONTAINERSTATS_CMD_MAX
+ */
+
+enum {
+ CONTAINERSTATS_CMD_UNSPEC = __TASKSTATS_CMD_MAX, /* Reserved */
+ CONTAINERSTATS_CMD_GET, /* user->kernel request/get-response */
+ CONTAINERSTATS_CMD_NEW, /* kernel->user event */
+ __CONTAINERSTATS_CMD_MAX,
+};
+
+#define CONTAINERSTATS_CMD_MAX (__CONTAINERSTATS_CMD_MAX - 1)
+
+enum {
+ CONTAINERSTATS_TYPE_UNSPEC = 0, /* Reserved */
+ CONTAINERSTATS_TYPE_CONTAINER_STATS, /* contains name + stats */
+ __CONTAINERSTATS_TYPE_MAX,
+};
+
+#define CONTAINERSTATS_TYPE_MAX (__CONTAINERSTATS_TYPE_MAX - 1)
+
+enum {
+ CONTAINERSTATS_CMD_ATTR_UNSPEC = 0,
+ CONTAINERSTATS_CMD_ATTR_FD,
+ __CONTAINERSTATS_CMD_ATTR_MAX,
+};
+
+#define CONTAINERSTATS_CMD_ATTR_MAX (__CONTAINERSTATS_CMD_ATTR_MAX - 1)
+
+#endif /* _LINUX_CONTAINERSTATS_H */
diff -puN include/linux/delayacct.h~containers-taskstats include/linux/delayacct.h
--- linux-2.6.22-rc24-mm2/include/linux/delayacct.h~containers-taskstats 2007-06-08 23:11:03.000000000 +0530
+++ linux-2.6.22-rc24-mm2-balbir/include/linux/delayacct.h 2007-06-08 23:11:03.000000000 +0530
@@ -26,6 +26,7 @@
* Used to set current->delays->flags
*/
#define DELAYACCT_PF_SWAPIN 0x00000001 /* I am doing a swapin */
+#define DELAYACCT_PF_BLKIO 0x00000002 /* I am waiting on IO */

#ifdef CONFIG_TASK_DELAY_ACCT

@@ -39,6 +40,14 @@ extern void __delayacct_blkio_end(void);
extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
extern __u64 __delayacct_blkio_ticks(struct task_struct *);

+static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
+{
+ if (p->delays)
+ return (p->delays->flags & DELAYACCT_PF_BLKIO);
+ else
+ return 0;
+}
+
static inline void delayacct_set_flag(int flag)
{
if (current->delays)
@@ -71,6 +80,7 @@ static inline void delayacct_tsk_free(st

static inline void delayacct_blkio_start(void)
{
+ delayacct_set_flag(DELAYACCT_PF_BLKIO);
if (current->delays)
__delayacct_blkio_start();
}
@@ -79,6 +89,7 @@ static inline void delayacct_blkio_end(v
{
if (current->delays)
__delayacct_blkio_end();
+ delayacct_clear_flag(DELAYACCT_PF_BLKIO);
}

static inline int delayacct_add_tsk(struct taskstats *d,
@@ -116,6 +127,8 @@ static inline int delayacct_add_tsk(stru
{ return 0; }
static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
{ return 0; }
+static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
+{ return 0; }
#endif /* CONFIG_TASK_DELAY_ACCT */

#endif
diff -puN include/linux/Kbuild~containers-taskstats include/linux/Kbuild
--- linux-2.6.22-rc24-mm2/include/linux/Kbuild~containers-taskstats 2007-06-08 23:11:03.000000000 +0530
+++ linux-2.6.22-rc24-mm2-balbir/include/linux/Kbuild 2007-06-08 23:11:03.000000000 +0530
@@ -47,6 +47,7 @@ header-y += coff.h
header-y += comstats.h
header-y += consolemap.h
header-y += const.h
+header-y += containerstats.h
header-y += cycx_cfm.h
header-y += dlm_device.h
header-y += dlm_netlink.h
diff -puN kernel/container.c~containers-taskstats kernel/container.c
--- linux-2.6.22-rc24-mm2/kernel/container.c~containers-taskstats 2007-06-08 23:11:03.000000000 +0530
+++ linux-2.6.22-rc24-mm2-balbir/kernel/container.c 2007-06-08 23:11:44.000000000 +0530
@@ -58,6 +58,8 @@
#include <linux/time.h>
#include <linux/backing-dev.h>
#include <linux/sort.h>
+#include <linux/delayacct.h>
+#include <linux/containerstats.h>

#include <asm/atomic.h>

@@ -1603,6 +1605,58 @@ static int pid_array_load(pid_t *pidarra
return n;
}

+/**
+ * Build and fill containerstats so that taskstats can export it to user
+ * space.
+ *
+ * @stats: containerstats to fill information into
+ * @dentry: A dentry entry belonging to the container for which stats have
+ * been requested.
+ */
+int containerstats_build(struct containerstats *stats, struct dentry *dentry)
+{
+ int ret = -EINVAL;
+ struct container *cont;
+ struct container_iter it;
+ struct task_struct *tsk;
+ /*
+ * Validate dentry by checking the superblock operations
+ */
+ if (dentry->d_sb->s_op != &container_ops)
+ goto err;
+
+ ret = 0;
+ cont = dentry->d_fsdata;
+ rcu_read_lock();
+
+ container_iter_start(cont, &it);
+ while ((tsk = container_iter_next(cont, &it))) {
+ switch (tsk->state) {
+ case TASK_RUNNING:
+ stats->nr_running++;
+ break;
+ case TASK_INTERRUPTIBLE:
+ stats->nr_sleeping++;
+ break;
+ case TASK_UNINTERRUPTIBLE:
+ stats->nr_uninterruptible++;
+ break;
+ case TASK_STOPPED:
+ stats->nr_stopped++;
+ break;
+ default:
+ if (delayacct_is_task_waiting_on_io(tsk))
+ stats->nr_io_wait++;
+ break;
+ }
+ }
+ container_iter_end(cont, &it);
+
+ rcu_read_unlock();
+err:
+ return ret;
+}
+
static int cmppid(const void *a, const void *b)
{
return *(pid_t *)a - *(pid_t *)b;
diff -puN kernel/sched.c~containers-taskstats kernel/sched.c
diff -puN kernel/taskstats.c~containers-taskstats kernel/taskstats.c
--- linux-2.6.22-rc24-mm2/kernel/taskstats.c~containers-taskstats 2007-06-08 23:11:03.000000000 +0530
+++ linux-2.6.22-rc24-mm2-balbir/kernel/taskstats.c 2007-06-08 23:11:03.000000000 +0530
@@ -23,6 +23,9 @@
#include <linux/tsacct_kern.h>
#include <linux/cpumask.h>
#include <linux/percpu.h>
+#include <linux/containerstats.h>
+#include <linux/container.h>
+#include <linux/file.h>
#include <net/genetlink.h>
#include <asm/atomic.h>

@@ -50,6 +53,11 @@ __read_mostly = {
[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING },
[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};

+static struct nla_policy
+containerstats_cmd_get_policy[CONTAINERSTATS_CMD_ATTR_MAX+1] __read_mostly = {
+ [CONTAINERSTATS_CMD_ATTR_FD] = { .type = NLA_U32 },
+};
+
struct listener {
struct list_head list;
pid_t pid;
@@ -373,6 +381,51 @@ err:
return NULL;
}

+static int containerstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
+{
+ int rc = 0;
+ struct sk_buff *rep_skb;
+ struct containerstats *stats;
+ struct nlattr *na;
+ size_t size;
+ u32 fd;
+ struct file *file;
+ int fput_needed;
+
+ na = info->attrs[CONTAINERSTATS_CMD_ATTR_FD];
+ if (!na)
+ return -EINVAL;
+
+ fd = nla_get_u32(info->attrs[CONTAINERSTATS_CMD_ATTR_FD]);
+ file = fget_light(fd, &fput_needed);
+ if (file) {
+ size = nla_total_size(sizeof(struct containerstats));
+
+ rc = prepare_reply(info, CONTAINERSTATS_CMD_NEW, &rep_skb,
+ size);
+ if (rc < 0)
+ goto err;
+
+ na = nla_reserve(rep_skb, CONTAINERSTATS_TYPE_CONTAINER_STATS,
+ sizeof(struct containerstats));
+ stats = nla_data(na);
+ memset(stats, 0, sizeof(*stats));
+
+ rc = containerstats_build(stats, file->f_dentry);
+ if (rc < 0)
+ goto err;
+
+ fput_light(file, fput_needed);
+ return send_reply(rep_skb, info->snd_pid);
+ }
+
+err:
+ if (file)
+ fput_light(file, fput_needed);
+ nlmsg_free(rep_skb);
+ return rc;
+}
+
static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
{
int rc = 0;
@@ -523,6 +576,12 @@ static struct genl_ops taskstats_ops = {
.policy = taskstats_cmd_get_policy,
};

+static struct genl_ops containerstats_ops = {
+ .cmd = CONTAINERSTATS_CMD_GET,
+ .doit = containerstats_user_cmd,
+ .policy = containerstats_cmd_get_policy,
+};
+
/* Needed early in initialization */
void __init taskstats_init_early(void)
{
@@ -547,8 +606,15 @@ static int __init taskstats_init(void)
if (rc < 0)
goto err;

+ rc = genl_register_ops(&family, &containerstats_ops);
+ if (rc < 0)
+ goto err_container_ops;
+
family_registered = 1;
+ printk("registered taskstats version %d\n", TASKSTATS_GENL_VERSION);
return 0;
+err_container_ops:
+ genl_unregister_ops(&family, &taskstats_ops);
err:
genl_unregister_family(&family);
return rc;
diff -puN kernel/cpuset.c~containers-taskstats kernel/cpuset.c
diff -puN kernel/delayacct.c~containers-taskstats kernel/delayacct.c
_

--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL