revert "Task Control Groups: example CPU accounting subsystem"

Revert 62d0df64065e7c135d0002f069444fbdfc64768f.

This was originally intended as a simple initial example of how to create a
control groups subsystem; it wasn't intended for mainline, but I didn't make
this clear enough to Andrew.

The CFS cgroup subsystem now has better functionality for the per-cgroup usage
accounting (based directly on CFS stats) than the "usage" status file in this
patch, and the "load" status file is rather simplistic - although having a
per-cgroup load average report would be a useful feature, I don't believe this
patch actually provides it.  If it gets into the final 2.6.24 we'd probably
have to support this interface for ever.

Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

6 files changed, 3 insertions, 225 deletions

diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
index 0b9bfbde8168..d62fcee9a08a 100644
--- a/include/linux/cgroup_subsys.h
+++ b/include/linux/cgroup_subsys.h
@@ -13,12 +13,6 @@ SUBSYS(cpuset)
 
 /* */
 
-#ifdef CONFIG_CGROUP_CPUACCT
-SUBSYS(cpuacct)
-#endif
-
-/* */
-
 #ifdef CONFIG_CGROUP_DEBUG
 SUBSYS(debug)
 #endif
diff --git a/include/linux/cpu_acct.h b/include/linux/cpu_acct.h
deleted file mode 100644
index 6b5fd8a66c8d..000000000000
--- a/include/linux/cpu_acct.h
+++ /dev/null
@@ -1,14 +0,0 @@
-
-#ifndef _LINUX_CPU_ACCT_H
-#define _LINUX_CPU_ACCT_H
-
-#include <linux/cgroup.h>
-#include <asm/cputime.h>
-
-#ifdef CONFIG_CGROUP_CPUACCT
-extern void cpuacct_charge(struct task_struct *, cputime_t cputime);
-#else
-static void inline cpuacct_charge(struct task_struct *p, cputime_t cputime) {}
-#endif
-
-#endif
diff --git a/init/Kconfig b/init/Kconfig
index 8b88d0bedcbd..5b92e3aa1366 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -301,13 +301,6 @@ config CGROUP_NS
           for instance virtual servers and checkpoint/restart
           jobs.
 
-config CGROUP_CPUACCT
-	bool "Simple CPU accounting cgroup subsystem"
-	depends on CGROUPS
-	help
-	  Provides a simple Resource Controller for monitoring the
-	  total CPU consumed by the tasks in a cgroup
-
 config CPUSETS
 	bool "Cpuset support"
 	depends on SMP && CGROUPS
diff --git a/kernel/Makefile b/kernel/Makefile
index f60afe742599..dfa96956dae0 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -40,7 +40,6 @@ obj-$(CONFIG_COMPAT) += compat.o
 obj-$(CONFIG_CGROUPS) += cgroup.o
 obj-$(CONFIG_CGROUP_DEBUG) += cgroup_debug.o
 obj-$(CONFIG_CPUSETS) += cpuset.o
-obj-$(CONFIG_CGROUP_CPUACCT) += cpu_acct.o
 obj-$(CONFIG_CGROUP_NS) += ns_cgroup.o
 obj-$(CONFIG_IKCONFIG) += configs.o
 obj-$(CONFIG_STOP_MACHINE) += stop_machine.o
diff --git a/kernel/cpu_acct.c b/kernel/cpu_acct.c
deleted file mode 100644
index 731e47e7f164..000000000000
--- a/kernel/cpu_acct.c
+++ /dev/null
@@ -1,186 +0,0 @@
-/*
- * kernel/cpu_acct.c - CPU accounting cgroup subsystem
- *
- * Copyright (C) Google Inc, 2006
- *
- * Developed by Paul Menage (menage@google.com) and Balbir Singh
- * (balbir@in.ibm.com)
- *
- */
-
-/*
- * Example cgroup subsystem for reporting total CPU usage of tasks in a
- * cgroup, along with percentage load over a time interval
- */
-
-#include <linux/module.h>
-#include <linux/cgroup.h>
-#include <linux/fs.h>
-#include <linux/rcupdate.h>
-
-#include <asm/div64.h>
-
-struct cpuacct {
-	struct cgroup_subsys_state css;
-	spinlock_t lock;
-	/* total time used by this class */
-	cputime64_t time;
-
-	/* time when next load calculation occurs */
-	u64 next_interval_check;
-
-	/* time used in current period */
-	cputime64_t current_interval_time;
-
-	/* time used in last period */
-	cputime64_t last_interval_time;
-};
-
-struct cgroup_subsys cpuacct_subsys;
-
-static inline struct cpuacct *cgroup_ca(struct cgroup *cont)
-{
-	return container_of(cgroup_subsys_state(cont, cpuacct_subsys_id),
-			    struct cpuacct, css);
-}
-
-static inline struct cpuacct *task_ca(struct task_struct *task)
-{
-	return container_of(task_subsys_state(task, cpuacct_subsys_id),
-			    struct cpuacct, css);
-}
-
-#define INTERVAL (HZ * 10)
-
-static inline u64 next_interval_boundary(u64 now)
-{
-	/* calculate the next interval boundary beyond the
-	 * current time */
-	do_div(now, INTERVAL);
-	return (now + 1) * INTERVAL;
-}
-
-static struct cgroup_subsys_state *cpuacct_create(
-	struct cgroup_subsys *ss, struct cgroup *cont)
-{
-	struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
-
-	if (!ca)
-		return ERR_PTR(-ENOMEM);
-	spin_lock_init(&ca->lock);
-	ca->next_interval_check = next_interval_boundary(get_jiffies_64());
-	return &ca->css;
-}
-
-static void cpuacct_destroy(struct cgroup_subsys *ss,
-			    struct cgroup *cont)
-{
-	kfree(cgroup_ca(cont));
-}
-
-/* Lazily update the load calculation if necessary. Called with ca locked */
-static void cpuusage_update(struct cpuacct *ca)
-{
-	u64 now = get_jiffies_64();
-
-	/* If we're not due for an update, return */
-	if (ca->next_interval_check > now)
-		return;
-
-	if (ca->next_interval_check <= (now - INTERVAL)) {
-		/* If it's been more than an interval since the last
-		 * check, then catch up - the last interval must have
-		 * been zero load */
-		ca->last_interval_time = 0;
-		ca->next_interval_check = next_interval_boundary(now);
-	} else {
-		/* If a steal takes the last interval time negative,
-		 * then we just ignore it */
-		if ((s64)ca->current_interval_time > 0)
-			ca->last_interval_time = ca->current_interval_time;
-		else
-			ca->last_interval_time = 0;
-		ca->next_interval_check += INTERVAL;
-	}
-	ca->current_interval_time = 0;
-}
-
-static u64 cpuusage_read(struct cgroup *cont, struct cftype *cft)
-{
-	struct cpuacct *ca = cgroup_ca(cont);
-	u64 time;
-
-	spin_lock_irq(&ca->lock);
-	cpuusage_update(ca);
-	time = cputime64_to_jiffies64(ca->time);
-	spin_unlock_irq(&ca->lock);
-
-	/* Convert 64-bit jiffies to seconds */
-	time *= 1000;
-	do_div(time, HZ);
-	return time;
-}
-
-static u64 load_read(struct cgroup *cont, struct cftype *cft)
-{
-	struct cpuacct *ca = cgroup_ca(cont);
-	u64 time;
-
-	/* Find the time used in the previous interval */
-	spin_lock_irq(&ca->lock);
-	cpuusage_update(ca);
-	time = cputime64_to_jiffies64(ca->last_interval_time);
-	spin_unlock_irq(&ca->lock);
-
-	/* Convert time to a percentage, to give the load in the
-	 * previous period */
-	time *= 100;
-	do_div(time, INTERVAL);
-
-	return time;
-}
-
-static struct cftype files[] = {
-	{
-		.name = "usage",
-		.read_uint = cpuusage_read,
-	},
-	{
-		.name = "load",
-		.read_uint = load_read,
-	}
-};
-
-static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cont)
-{
-	return cgroup_add_files(cont, ss, files, ARRAY_SIZE(files));
-}
-
-void cpuacct_charge(struct task_struct *task, cputime_t cputime)
-{
-
-	struct cpuacct *ca;
-	unsigned long flags;
-
-	if (!cpuacct_subsys.active)
-		return;
-	rcu_read_lock();
-	ca = task_ca(task);
-	if (ca) {
-		spin_lock_irqsave(&ca->lock, flags);
-		cpuusage_update(ca);
-		ca->time = cputime64_add(ca->time, cputime);
-		ca->current_interval_time =
-			cputime64_add(ca->current_interval_time, cputime);
-		spin_unlock_irqrestore(&ca->lock, flags);
-	}
-	rcu_read_unlock();
-}
-
-struct cgroup_subsys cpuacct_subsys = {
-	.name = "cpuacct",
-	.create = cpuacct_create,
-	.destroy = cpuacct_destroy,
-	.populate = cpuacct_populate,
-	.subsys_id = cpuacct_subsys_id,
-};
diff --git a/kernel/sched.c b/kernel/sched.c
index b18f231a4875..4fb3532dd7e8 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -52,7 +52,6 @@
 #include <linux/cpu.h>
 #include <linux/cpuset.h>
 #include <linux/percpu.h>
-#include <linux/cpu_acct.h>
 #include <linux/kthread.h>
 #include <linux/seq_file.h>
 #include <linux/sysctl.h>
@@ -3338,13 +3337,9 @@ void account_user_time(struct task_struct *p, cputime_t cputime)
 {
 	struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
 	cputime64_t tmp;
-	struct rq *rq = this_rq();
 
 	p->utime = cputime_add(p->utime, cputime);
 
-	if (p != rq->idle)
-		cpuacct_charge(p, cputime);
-
 	/* Add user time to cpustat. */
 	tmp = cputime_to_cputime64(cputime);
 	if (TASK_NICE(p) > 0)
@@ -3408,10 +3403,9 @@ void account_system_time(struct task_struct *p, int hardirq_offset,
 		cpustat->irq = cputime64_add(cpustat->irq, tmp);
 	else if (softirq_count())
 		cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
-	else if (p != rq->idle) {
+	else if (p != rq->idle)
 		cpustat->system = cputime64_add(cpustat->system, tmp);
-		cpuacct_charge(p, cputime);
-	} else if (atomic_read(&rq->nr_iowait) > 0)
+	else if (atomic_read(&rq->nr_iowait) > 0)
 		cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
 	else
 		cpustat->idle = cputime64_add(cpustat->idle, tmp);
@@ -3447,10 +3441,8 @@ void account_steal_time(struct task_struct *p, cputime_t steal)
 			cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
 		else
 			cpustat->idle = cputime64_add(cpustat->idle, tmp);
-	} else {
+	} else
 		cpustat->steal = cputime64_add(cpustat->steal, tmp);
-		cpuacct_charge(p, -tmp);
-	}
 }
 
 /*