From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jin Qian <jinqian@google.com>
Date: Wed, 11 Mar 2015 10:44:50 -0700
Subject: ANDROID: uid_cputime: Adds accounting for the cputimes per uid.

Adds proc files /proc/uid_cputime/show_uid_stat and
/proc/uid_cputime/remove_uid_range.

show_uid_stat lists the total utime and stime for the active as well as
terminated processes for each of the uids.

Writing a range of uids to remove_uid_range will delete the accounting
for all the uids within that range.

[CPNOTE: 01/07/21] Lee: Requested status on the bug

Bug: 34198239
Bug: 120442023
Bug: 133273154
Bug: 146339763
Change-Id: I21d9210379da730b33ddc1a0ea663c8c9d2ac15b
Signed-off-by: Jin Qian <jinqian@google.com>
[AmitP: Refactored the original patch because upstream commit
        605dc2b31a2a ("tsacct: Convert obsolete cputime type to nsecs")
        made cputime_t type obsolete, so use u64 nanoseconds directly instead.
        Also folded following android-4.9 changes into this patch
        48a9906c0fd8 ("ANDROID: proc: uid_cputime: create uids from kuids")
        453ac31cab34 ("ANDROID: proc: uid_cputime: fix show_uid_stat permission")]
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
[connoro: Used by batterystats.]
[adelva: Folded in the file/kconfig rename and the following changes:
         da3687fbc393 ("ANDROID: uid_cputime: fix cputime overflow")
         71e3eb512d00 ("ANDROID: uid_cputime: Iterates over all the threads instead of processes.")
         c65f0080c300 ("ANDROID: uid_cputime: Check for the range while removing range of UIDs.")
         c8212458e3a5 ("ANDROID: uid_sys_stats: fix access of task_uid(task)")
         bb5ee21cc4dd ("ANDROID: uid_sys_stats: change to use rt_mutex")
         6dc5d8173a8c ("ANDROID: uid_sys_stats: check previous uid_entry before call find_or_register_uid")
         82b9872b3894 ("ANDROID: uid_sys_stats: Replace tasklist lock with RCU in uid_cputime_show")]
Signed-off-by: Alistair Delva <adelva@google.com>
[ebiggers: Folded in the applicable parts of the following commits:
           860f41ebc85e ("ANDROID: fix up uio_sys_stats to handle recent proc_ops changes")
           953d6c5a9514 ("ANDROID: uid_sys_stats: avoid double accounting of dying threads").
           Also folded in some refactoring from commit
           ecc74079f610 ("ANDROID: uid_cputime: add per-uid IO usage accounting")]
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 drivers/misc/Kconfig         |  15 +
 drivers/misc/Makefile        |   1 +
 drivers/misc/uid_sys_stats.c | 704 +++++++++++++++++++++++++++++++++++
 3 files changed, 720 insertions(+)
 create mode 100644 drivers/misc/uid_sys_stats.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -460,6 +460,21 @@ config MISC_RTSX
 	tristate
 	default MISC_RTSX_PCI || MISC_RTSX_USB
 
+config UID_SYS_STATS
+	bool "Per-UID statistics"
+	depends on PROFILING && TASK_IO_ACCOUNTING
+	help
+	  Per UID based cpu time statistics exported to /proc/uid_cputime
+	  Per UID based io statistics exported to /proc/uid_io
+	  Per UID based procstat control in /proc/uid_procstat
+
+config UID_SYS_STATS_DEBUG
+	bool "Per-TASK statistics"
+	depends on UID_SYS_STATS
+	default n
+	help
+	  Per TASK based io statistics exported to /proc/uid_io
+
 config HISI_HIKEY_USB
 	tristate "USB GPIO Hub on HiSilicon Hikey 960/970 Platform"
 	depends on (OF && GPIOLIB) || COMPILE_TEST
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -59,3 +59,4 @@ obj-$(CONFIG_UACCE)		+= uacce/
 obj-$(CONFIG_XILINX_SDFEC)	+= xilinx_sdfec.o
 obj-$(CONFIG_HISI_HIKEY_USB)	+= hisi_hikey_usb.o
 obj-$(CONFIG_HI6421V600_IRQ)	+= hi6421v600-irq.o
+obj-$(CONFIG_UID_SYS_STATS)	+= uid_sys_stats.o
diff --git a/drivers/misc/uid_sys_stats.c b/drivers/misc/uid_sys_stats.c
new file mode 100644
--- /dev/null
+++ b/drivers/misc/uid_sys_stats.c
@@ -0,0 +1,704 @@
+/* drivers/misc/uid_sys_stats.c
+ *
+ * Copyright (C) 2014 - 2015 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/atomic.h>
+#include <linux/err.h>
+#include <linux/hashtable.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/proc_fs.h>
+#include <linux/profile.h>
+#include <linux/rtmutex.h>
+#include <linux/sched/cputime.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+
+#define UID_HASH_BITS	10
+DECLARE_HASHTABLE(hash_table, UID_HASH_BITS);
+
+static DEFINE_RT_MUTEX(uid_lock);
+static struct proc_dir_entry *cpu_parent;
+static struct proc_dir_entry *io_parent;
+static struct proc_dir_entry *proc_parent;
+
+struct io_stats {
+	u64 read_bytes;
+	u64 write_bytes;
+	u64 rchar;
+	u64 wchar;
+	u64 fsync;
+};
+
+#define UID_STATE_FOREGROUND	0
+#define UID_STATE_BACKGROUND	1
+#define UID_STATE_BUCKET_SIZE	2
+
+#define UID_STATE_TOTAL_CURR	2
+#define UID_STATE_TOTAL_LAST	3
+#define UID_STATE_DEAD_TASKS	4
+#define UID_STATE_SIZE		5
+
+#define MAX_TASK_COMM_LEN 256
+
+struct task_entry {
+	char comm[MAX_TASK_COMM_LEN];
+	pid_t pid;
+	struct io_stats io[UID_STATE_SIZE];
+	struct hlist_node hash;
+};
+
+struct uid_entry {
+	uid_t uid;
+	u64 utime;
+	u64 stime;
+	u64 active_utime;
+	u64 active_stime;
+	int state;
+	struct io_stats io[UID_STATE_SIZE];
+	struct hlist_node hash;
+#ifdef CONFIG_UID_SYS_STATS_DEBUG
+	DECLARE_HASHTABLE(task_entries, UID_HASH_BITS);
+#endif
+};
+
+static u64 compute_write_bytes(struct task_struct *task)
+{
+	if (task->ioac.write_bytes <= task->ioac.cancelled_write_bytes)
+		return 0;
+
+	return task->ioac.write_bytes - task->ioac.cancelled_write_bytes;
+}
+
+static void compute_io_bucket_stats(struct io_stats *io_bucket,
+					struct io_stats *io_curr,
+					struct io_stats *io_last,
+					struct io_stats *io_dead)
+{
+	/* tasks could switch to another uid group, but its io_last in the
+	 * previous uid group could still be positive.
+	 * therefore before each update, do an overflow check first
+	 */
+	int64_t delta;
+
+	delta = io_curr->read_bytes + io_dead->read_bytes -
+		io_last->read_bytes;
+	io_bucket->read_bytes += delta > 0 ? delta : 0;
+	delta = io_curr->write_bytes + io_dead->write_bytes -
+		io_last->write_bytes;
+	io_bucket->write_bytes += delta > 0 ? delta : 0;
+	delta = io_curr->rchar + io_dead->rchar - io_last->rchar;
+	io_bucket->rchar += delta > 0 ? delta : 0;
+	delta = io_curr->wchar + io_dead->wchar - io_last->wchar;
+	io_bucket->wchar += delta > 0 ? delta : 0;
+	delta = io_curr->fsync + io_dead->fsync - io_last->fsync;
+	io_bucket->fsync += delta > 0 ? delta : 0;
+
+	io_last->read_bytes = io_curr->read_bytes;
+	io_last->write_bytes = io_curr->write_bytes;
+	io_last->rchar = io_curr->rchar;
+	io_last->wchar = io_curr->wchar;
+	io_last->fsync = io_curr->fsync;
+
+	memset(io_dead, 0, sizeof(struct io_stats));
+}
+
+#ifdef CONFIG_UID_SYS_STATS_DEBUG
+static void get_full_task_comm(struct task_entry *task_entry,
+		struct task_struct *task)
+{
+	int i = 0, offset = 0, len = 0;
+	/* save one byte for terminating null character */
+	int unused_len = MAX_TASK_COMM_LEN - TASK_COMM_LEN - 1;
+	char buf[MAX_TASK_COMM_LEN - TASK_COMM_LEN - 1];
+	struct mm_struct *mm = task->mm;
+
+	/* fill the first TASK_COMM_LEN bytes with thread name */
+	__get_task_comm(task_entry->comm, TASK_COMM_LEN, task);
+	i = strlen(task_entry->comm);
+	while (i < TASK_COMM_LEN)
+		task_entry->comm[i++] = ' ';
+
+	/* next the executable file name */
+	if (mm) {
+		mmap_write_lock(mm);
+		if (mm->exe_file) {
+			char *pathname = d_path(&mm->exe_file->f_path, buf,
+					unused_len);
+
+			if (!IS_ERR(pathname)) {
+				len = strlcpy(task_entry->comm + i, pathname,
+						unused_len);
+				i += len;
+				task_entry->comm[i++] = ' ';
+				unused_len--;
+			}
+		}
+		mmap_write_unlock(mm);
+	}
+	unused_len -= len;
+
+	/* fill the rest with command line argument
+	 * replace each null or new line character
+	 * between args in argv with whitespace */
+	len = get_cmdline(task, buf, unused_len);
+	while (offset < len) {
+		if (buf[offset] != '\0' && buf[offset] != '\n')
+			task_entry->comm[i++] = buf[offset];
+		else
+			task_entry->comm[i++] = ' ';
+		offset++;
+	}
+
+	/* get rid of trailing whitespaces in case when arg is memset to
+	 * zero before being reset in userspace
+	 */
+	while (task_entry->comm[i-1] == ' ')
+		i--;
+	task_entry->comm[i] = '\0';
+}
+
+static struct task_entry *find_task_entry(struct uid_entry *uid_entry,
+		struct task_struct *task)
+{
+	struct task_entry *task_entry;
+
+	hash_for_each_possible(uid_entry->task_entries, task_entry, hash,
+			task->pid) {
+		if (task->pid == task_entry->pid) {
+			/* if thread name changed, update the entire command */
+			int len = strnchr(task_entry->comm, ' ', TASK_COMM_LEN)
+				- task_entry->comm;
+
+			if (strncmp(task_entry->comm, task->comm, len))
+				get_full_task_comm(task_entry, task);
+			return task_entry;
+		}
+	}
+	return NULL;
+}
+
+static struct task_entry *find_or_register_task(struct uid_entry *uid_entry,
+		struct task_struct *task)
+{
+	struct task_entry *task_entry;
+	pid_t pid = task->pid;
+
+	task_entry = find_task_entry(uid_entry, task);
+	if (task_entry)
+		return task_entry;
+
+	task_entry = kzalloc(sizeof(struct task_entry), GFP_ATOMIC);
+	if (!task_entry)
+		return NULL;
+
+	get_full_task_comm(task_entry, task);
+
+	task_entry->pid = pid;
+	hash_add(uid_entry->task_entries, &task_entry->hash, (unsigned int)pid);
+
+	return task_entry;
+}
+
+static void remove_uid_tasks(struct uid_entry *uid_entry)
+{
+	struct task_entry *task_entry;
+	unsigned long bkt_task;
+	struct hlist_node *tmp_task;
+
+	hash_for_each_safe(uid_entry->task_entries, bkt_task,
+			tmp_task, task_entry, hash) {
+		hash_del(&task_entry->hash);
+		kfree(task_entry);
+	}
+}
+
+static void set_io_uid_tasks_zero(struct uid_entry *uid_entry)
+{
+	struct task_entry *task_entry;
+	unsigned long bkt_task;
+
+	hash_for_each(uid_entry->task_entries, bkt_task, task_entry, hash) {
+		memset(&task_entry->io[UID_STATE_TOTAL_CURR], 0,
+			sizeof(struct io_stats));
+	}
+}
+
+static void add_uid_tasks_io_stats(struct uid_entry *uid_entry,
+		struct task_struct *task, int slot)
+{
+	struct task_entry *task_entry = find_or_register_task(uid_entry, task);
+	struct io_stats *task_io_slot = &task_entry->io[slot];
+
+	task_io_slot->read_bytes += task->ioac.read_bytes;
+	task_io_slot->write_bytes += compute_write_bytes(task);
+	task_io_slot->rchar += task->ioac.rchar;
+	task_io_slot->wchar += task->ioac.wchar;
+}
+
+static void compute_io_uid_tasks(struct uid_entry *uid_entry)
+{
+	struct task_entry *task_entry;
+	unsigned long bkt_task;
+
+	hash_for_each(uid_entry->task_entries, bkt_task, task_entry, hash) {
+		compute_io_bucket_stats(&task_entry->io[uid_entry->state],
+					&task_entry->io[UID_STATE_TOTAL_CURR],
+					&task_entry->io[UID_STATE_TOTAL_LAST],
+					&task_entry->io[UID_STATE_DEAD_TASKS]);
+	}
+}
+
+static void show_io_uid_tasks(struct seq_file *m, struct uid_entry *uid_entry)
+{
+	struct task_entry *task_entry;
+	unsigned long bkt_task;
+
+	hash_for_each(uid_entry->task_entries, bkt_task, task_entry, hash) {
+		/* Separated by comma because space exists in task comm */
+		seq_printf(m, "task,%s,%lu,%llu,%llu,%llu,%llu,%llu,%llu,%llu,%llu,%llu,%llu\n",
+				task_entry->comm,
+				(unsigned long)task_entry->pid,
+				task_entry->io[UID_STATE_FOREGROUND].rchar,
+				task_entry->io[UID_STATE_FOREGROUND].wchar,
+				task_entry->io[UID_STATE_FOREGROUND].read_bytes,
+				task_entry->io[UID_STATE_FOREGROUND].write_bytes,
+				task_entry->io[UID_STATE_BACKGROUND].rchar,
+				task_entry->io[UID_STATE_BACKGROUND].wchar,
+				task_entry->io[UID_STATE_BACKGROUND].read_bytes,
+				task_entry->io[UID_STATE_BACKGROUND].write_bytes,
+				task_entry->io[UID_STATE_FOREGROUND].fsync,
+				task_entry->io[UID_STATE_BACKGROUND].fsync);
+	}
+}
+#else
+static void remove_uid_tasks(struct uid_entry *uid_entry) {};
+static void set_io_uid_tasks_zero(struct uid_entry *uid_entry) {};
+static void add_uid_tasks_io_stats(struct uid_entry *uid_entry,
+		struct task_struct *task, int slot) {};
+static void compute_io_uid_tasks(struct uid_entry *uid_entry) {};
+static void show_io_uid_tasks(struct seq_file *m,
+		struct uid_entry *uid_entry) {}
+#endif
+
+static struct uid_entry *find_uid_entry(uid_t uid)
+{
+	struct uid_entry *uid_entry;
+	hash_for_each_possible(hash_table, uid_entry, hash, uid) {
+		if (uid_entry->uid == uid)
+			return uid_entry;
+	}
+	return NULL;
+}
+
+static struct uid_entry *find_or_register_uid(uid_t uid)
+{
+	struct uid_entry *uid_entry;
+
+	uid_entry = find_uid_entry(uid);
+	if (uid_entry)
+		return uid_entry;
+
+	uid_entry = kzalloc(sizeof(struct uid_entry), GFP_ATOMIC);
+	if (!uid_entry)
+		return NULL;
+
+	uid_entry->uid = uid;
+#ifdef CONFIG_UID_SYS_STATS_DEBUG
+	hash_init(uid_entry->task_entries);
+#endif
+	hash_add(hash_table, &uid_entry->hash, uid);
+
+	return uid_entry;
+}
+
+static int uid_cputime_show(struct seq_file *m, void *v)
+{
+	struct uid_entry *uid_entry = NULL;
+	struct task_struct *task, *temp;
+	struct user_namespace *user_ns = current_user_ns();
+	u64 utime;
+	u64 stime;
+	unsigned long bkt;
+	uid_t uid;
+
+	rt_mutex_lock(&uid_lock);
+
+	hash_for_each(hash_table, bkt, uid_entry, hash) {
+		uid_entry->active_stime = 0;
+		uid_entry->active_utime = 0;
+	}
+
+	rcu_read_lock();
+	do_each_thread(temp, task) {
+		uid = from_kuid_munged(user_ns, task_uid(task));
+		if (!uid_entry || uid_entry->uid != uid)
+			uid_entry = find_or_register_uid(uid);
+		if (!uid_entry) {
+			rcu_read_unlock();
+			rt_mutex_unlock(&uid_lock);
+			pr_err("%s: failed to find the uid_entry for uid %d\n",
+				__func__, uid);
+			return -ENOMEM;
+		}
+		/* avoid double accounting of dying threads */
+		if (!(task->flags & PF_EXITING)) {
+			task_cputime_adjusted(task, &utime, &stime);
+			uid_entry->active_utime += utime;
+			uid_entry->active_stime += stime;
+		}
+	} while_each_thread(temp, task);
+	rcu_read_unlock();
+
+	hash_for_each(hash_table, bkt, uid_entry, hash) {
+		u64 total_utime = uid_entry->utime +
+							uid_entry->active_utime;
+		u64 total_stime = uid_entry->stime +
+							uid_entry->active_stime;
+		seq_printf(m, "%d: %llu %llu\n", uid_entry->uid,
+			ktime_to_us(total_utime), ktime_to_us(total_stime));
+	}
+
+	rt_mutex_unlock(&uid_lock);
+	return 0;
+}
+
+static int uid_cputime_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, uid_cputime_show, PDE_DATA(inode));
+}
+
+static const struct proc_ops uid_cputime_fops = {
+	.proc_open	= uid_cputime_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= single_release,
+};
+
+static int uid_remove_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, NULL, NULL);
+}
+
+static ssize_t uid_remove_write(struct file *file,
+			const char __user *buffer, size_t count, loff_t *ppos)
+{
+	struct uid_entry *uid_entry;
+	struct hlist_node *tmp;
+	char uids[128];
+	char *start_uid, *end_uid = NULL;
+	long int uid_start = 0, uid_end = 0;
+
+	if (count >= sizeof(uids))
+		count = sizeof(uids) - 1;
+
+	if (copy_from_user(uids, buffer, count))
+		return -EFAULT;
+
+	uids[count] = '\0';
+	end_uid = uids;
+	start_uid = strsep(&end_uid, "-");
+
+	if (!start_uid || !end_uid)
+		return -EINVAL;
+
+	if (kstrtol(start_uid, 10, &uid_start) != 0 ||
+		kstrtol(end_uid, 10, &uid_end) != 0) {
+		return -EINVAL;
+	}
+
+	rt_mutex_lock(&uid_lock);
+
+	for (; uid_start <= uid_end; uid_start++) {
+		hash_for_each_possible_safe(hash_table, uid_entry, tmp,
+							hash, (uid_t)uid_start) {
+			if (uid_start == uid_entry->uid) {
+				remove_uid_tasks(uid_entry);
+				hash_del(&uid_entry->hash);
+				kfree(uid_entry);
+			}
+		}
+	}
+
+	rt_mutex_unlock(&uid_lock);
+	return count;
+}
+
+static const struct proc_ops uid_remove_fops = {
+	.proc_open	= uid_remove_open,
+	.proc_release	= single_release,
+	.proc_write	= uid_remove_write,
+};
+
+
+static void add_uid_io_stats(struct uid_entry *uid_entry,
+			struct task_struct *task, int slot)
+{
+	struct io_stats *io_slot = &uid_entry->io[slot];
+
+	/* avoid double accounting of dying threads */
+	if (slot != UID_STATE_DEAD_TASKS && (task->flags & PF_EXITING))
+		return;
+
+	io_slot->read_bytes += task->ioac.read_bytes;
+	io_slot->write_bytes += compute_write_bytes(task);
+	io_slot->rchar += task->ioac.rchar;
+	io_slot->wchar += task->ioac.wchar;
+
+	add_uid_tasks_io_stats(uid_entry, task, slot);
+}
+
+static void update_io_stats_all_locked(void)
+{
+	struct uid_entry *uid_entry = NULL;
+	struct task_struct *task, *temp;
+	struct user_namespace *user_ns = current_user_ns();
+	unsigned long bkt;
+	uid_t uid;
+
+	hash_for_each(hash_table, bkt, uid_entry, hash) {
+		memset(&uid_entry->io[UID_STATE_TOTAL_CURR], 0,
+			sizeof(struct io_stats));
+		set_io_uid_tasks_zero(uid_entry);
+	}
+
+	rcu_read_lock();
+	do_each_thread(temp, task) {
+		uid = from_kuid_munged(user_ns, task_uid(task));
+		if (!uid_entry || uid_entry->uid != uid)
+			uid_entry = find_or_register_uid(uid);
+		if (!uid_entry)
+			continue;
+		add_uid_io_stats(uid_entry, task, UID_STATE_TOTAL_CURR);
+	} while_each_thread(temp, task);
+	rcu_read_unlock();
+
+	hash_for_each(hash_table, bkt, uid_entry, hash) {
+		compute_io_bucket_stats(&uid_entry->io[uid_entry->state],
+					&uid_entry->io[UID_STATE_TOTAL_CURR],
+					&uid_entry->io[UID_STATE_TOTAL_LAST],
+					&uid_entry->io[UID_STATE_DEAD_TASKS]);
+		compute_io_uid_tasks(uid_entry);
+	}
+}
+
+static void update_io_stats_uid_locked(struct uid_entry *uid_entry)
+{
+	struct task_struct *task, *temp;
+	struct user_namespace *user_ns = current_user_ns();
+
+	memset(&uid_entry->io[UID_STATE_TOTAL_CURR], 0,
+		sizeof(struct io_stats));
+	set_io_uid_tasks_zero(uid_entry);
+
+	rcu_read_lock();
+	do_each_thread(temp, task) {
+		if (from_kuid_munged(user_ns, task_uid(task)) != uid_entry->uid)
+			continue;
+		add_uid_io_stats(uid_entry, task, UID_STATE_TOTAL_CURR);
+	} while_each_thread(temp, task);
+	rcu_read_unlock();
+
+	compute_io_bucket_stats(&uid_entry->io[uid_entry->state],
+				&uid_entry->io[UID_STATE_TOTAL_CURR],
+				&uid_entry->io[UID_STATE_TOTAL_LAST],
+				&uid_entry->io[UID_STATE_DEAD_TASKS]);
+	compute_io_uid_tasks(uid_entry);
+}
+
+
+static int uid_io_show(struct seq_file *m, void *v)
+{
+	struct uid_entry *uid_entry;
+	unsigned long bkt;
+
+	rt_mutex_lock(&uid_lock);
+
+	update_io_stats_all_locked();
+
+	hash_for_each(hash_table, bkt, uid_entry, hash) {
+		seq_printf(m, "%d %llu %llu %llu %llu %llu %llu %llu %llu %llu %llu\n",
+				uid_entry->uid,
+				uid_entry->io[UID_STATE_FOREGROUND].rchar,
+				uid_entry->io[UID_STATE_FOREGROUND].wchar,
+				uid_entry->io[UID_STATE_FOREGROUND].read_bytes,
+				uid_entry->io[UID_STATE_FOREGROUND].write_bytes,
+				uid_entry->io[UID_STATE_BACKGROUND].rchar,
+				uid_entry->io[UID_STATE_BACKGROUND].wchar,
+				uid_entry->io[UID_STATE_BACKGROUND].read_bytes,
+				uid_entry->io[UID_STATE_BACKGROUND].write_bytes,
+				uid_entry->io[UID_STATE_FOREGROUND].fsync,
+				uid_entry->io[UID_STATE_BACKGROUND].fsync);
+
+		show_io_uid_tasks(m, uid_entry);
+	}
+
+	rt_mutex_unlock(&uid_lock);
+	return 0;
+}
+
+static int uid_io_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, uid_io_show, PDE_DATA(inode));
+}
+
+static const struct proc_ops uid_io_fops = {
+	.proc_open	= uid_io_open,
+	.proc_read	= seq_read,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= single_release,
+};
+
+static int uid_procstat_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, NULL, NULL);
+}
+
+static ssize_t uid_procstat_write(struct file *file,
+			const char __user *buffer, size_t count, loff_t *ppos)
+{
+	struct uid_entry *uid_entry;
+	uid_t uid;
+	int argc, state;
+	char input[128];
+
+	if (count >= sizeof(input))
+		return -EINVAL;
+
+	if (copy_from_user(input, buffer, count))
+		return -EFAULT;
+
+	input[count] = '\0';
+
+	argc = sscanf(input, "%u %d", &uid, &state);
+	if (argc != 2)
+		return -EINVAL;
+
+	if (state != UID_STATE_BACKGROUND && state != UID_STATE_FOREGROUND)
+		return -EINVAL;
+
+	rt_mutex_lock(&uid_lock);
+
+	uid_entry = find_or_register_uid(uid);
+	if (!uid_entry) {
+		rt_mutex_unlock(&uid_lock);
+		return -EINVAL;
+	}
+
+	if (uid_entry->state == state) {
+		rt_mutex_unlock(&uid_lock);
+		return count;
+	}
+
+	update_io_stats_uid_locked(uid_entry);
+
+	uid_entry->state = state;
+
+	rt_mutex_unlock(&uid_lock);
+
+	return count;
+}
+
+static const struct proc_ops uid_procstat_fops = {
+	.proc_open	= uid_procstat_open,
+	.proc_release	= single_release,
+	.proc_write	= uid_procstat_write,
+};
+
+static int process_notifier(struct notifier_block *self,
+			unsigned long cmd, void *v)
+{
+	struct task_struct *task = v;
+	struct uid_entry *uid_entry;
+	u64 utime, stime;
+	uid_t uid;
+
+	if (!task)
+		return NOTIFY_OK;
+
+	rt_mutex_lock(&uid_lock);
+	uid = from_kuid_munged(current_user_ns(), task_uid(task));
+	uid_entry = find_or_register_uid(uid);
+	if (!uid_entry) {
+		pr_err("%s: failed to find uid %d\n", __func__, uid);
+		goto exit;
+	}
+
+	task_cputime_adjusted(task, &utime, &stime);
+	uid_entry->utime += utime;
+	uid_entry->stime += stime;
+
+	add_uid_io_stats(uid_entry, task, UID_STATE_DEAD_TASKS);
+
+exit:
+	rt_mutex_unlock(&uid_lock);
+	return NOTIFY_OK;
+}
+
+static struct notifier_block process_notifier_block = {
+	.notifier_call	= process_notifier,
+};
+
+static int __init proc_uid_sys_stats_init(void)
+{
+	hash_init(hash_table);
+
+	cpu_parent = proc_mkdir("uid_cputime", NULL);
+	if (!cpu_parent) {
+		pr_err("%s: failed to create uid_cputime proc entry\n",
+			__func__);
+		goto err;
+	}
+
+	proc_create_data("remove_uid_range", 0222, cpu_parent,
+		&uid_remove_fops, NULL);
+	proc_create_data("show_uid_stat", 0444, cpu_parent,
+		&uid_cputime_fops, NULL);
+
+	io_parent = proc_mkdir("uid_io", NULL);
+	if (!io_parent) {
+		pr_err("%s: failed to create uid_io proc entry\n",
+			__func__);
+		goto err;
+	}
+
+	proc_create_data("stats", 0444, io_parent,
+		&uid_io_fops, NULL);
+
+	proc_parent = proc_mkdir("uid_procstat", NULL);
+	if (!proc_parent) {
+		pr_err("%s: failed to create uid_procstat proc entry\n",
+			__func__);
+		goto err;
+	}
+
+	proc_create_data("set", 0222, proc_parent,
+		&uid_procstat_fops, NULL);
+
+	profile_event_register(PROFILE_TASK_EXIT, &process_notifier_block);
+
+	return 0;
+
+err:
+	remove_proc_subtree("uid_cputime", NULL);
+	remove_proc_subtree("uid_io", NULL);
+	remove_proc_subtree("uid_procstat", NULL);
+	return -ENOMEM;
+}
+
+early_initcall(proc_uid_sys_stats_init);