This example demonstrates how to use the generic container subsystem
for a simple resource tracker that counts, for the processes in a
container, the total CPU time used and the %CPU used in the last
complete 10 second interval.

Portions contributed by Balbir Singh <[EMAIL PROTECTED]>

Signed-off-by: Paul Menage <[EMAIL PROTECTED]>

---
 include/linux/container_subsys.h |    6 +
 include/linux/cpu_acct.h         |   14 ++
 init/Kconfig                     |    7 +
 kernel/Makefile                  |    1 
 kernel/cpu_acct.c                |  185 +++++++++++++++++++++++++++++++++++++++
 kernel/sched.c                   |   14 ++
 6 files changed, 224 insertions(+), 3 deletions(-)

Index: container-2.6.22-rc2-mm1/include/linux/container_subsys.h
===================================================================
--- container-2.6.22-rc2-mm1.orig/include/linux/container_subsys.h
+++ container-2.6.22-rc2-mm1/include/linux/container_subsys.h
@@ -7,4 +7,10 @@
 
 /* */
 
+#ifdef CONFIG_CONTAINER_CPUACCT
+SUBSYS(cpuacct)
+#endif
+
+/* */
+
 /* */
Index: container-2.6.22-rc2-mm1/include/linux/cpu_acct.h
===================================================================
--- /dev/null
+++ container-2.6.22-rc2-mm1/include/linux/cpu_acct.h
@@ -0,0 +1,14 @@
+
+#ifndef _LINUX_CPU_ACCT_H
+#define _LINUX_CPU_ACCT_H
+
+#include <linux/container.h>
+#include <asm/cputime.h>
+
+#ifdef CONFIG_CONTAINER_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
Index: container-2.6.22-rc2-mm1/init/Kconfig
===================================================================
--- container-2.6.22-rc2-mm1.orig/init/Kconfig
+++ container-2.6.22-rc2-mm1/init/Kconfig
@@ -337,6 +337,13 @@ config SYSFS_DEPRECATED
          If you are using a distro that was released in 2006 or later,
          it should be safe to say N here.
 
+config CONTAINER_CPUACCT
+       bool "Simple CPU accounting container subsystem"
+       select CONTAINERS
+       help
+         Provides a simple Resource Controller for monitoring the
+         total CPU consumed by the tasks in a container
+
 config RELAY
        bool "Kernel->user space relay support (formerly relayfs)"
        help
Index: container-2.6.22-rc2-mm1/kernel/Makefile
===================================================================
--- container-2.6.22-rc2-mm1.orig/kernel/Makefile
+++ container-2.6.22-rc2-mm1/kernel/Makefile
@@ -38,6 +38,7 @@ obj-$(CONFIG_KEXEC) += kexec.o
 obj-$(CONFIG_COMPAT) += compat.o
 obj-$(CONFIG_CONTAINERS) += container.o
 obj-$(CONFIG_CPUSETS) += cpuset.o
+obj-$(CONFIG_CONTAINER_CPUACCT) += cpu_acct.o
 obj-$(CONFIG_IKCONFIG) += configs.o
 obj-$(CONFIG_STOP_MACHINE) += stop_machine.o
 obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
Index: container-2.6.22-rc2-mm1/kernel/cpu_acct.c
===================================================================
--- /dev/null
+++ container-2.6.22-rc2-mm1/kernel/cpu_acct.c
@@ -0,0 +1,185 @@
+/*
+ * kernel/cpu_acct.c - CPU accounting container subsystem
+ *
+ * Copyright (C) Google Inc, 2006
+ *
+ * Developed by Paul Menage ([EMAIL PROTECTED]) and Balbir Singh
+ * ([EMAIL PROTECTED])
+ *
+ */
+
+/*
+ * Example container subsystem for reporting total CPU usage of tasks in a
+ * container, along with percentage load over a time interval
+ */
+
+#include <linux/module.h>
+#include <linux/container.h>
+#include <linux/fs.h>
+#include <asm/div64.h>
+
+struct cpuacct {
+       struct container_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 container_subsys cpuacct_subsys;
+
+static inline struct cpuacct *container_ca(struct container *cont)
+{
+       return container_of(container_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 int cpuacct_create(struct container_subsys *ss, struct container *cont)
+{
+       struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
+       if (!ca)
+               return -ENOMEM;
+       spin_lock_init(&ca->lock);
+       ca->next_interval_check = next_interval_boundary(get_jiffies_64());
+       cont->subsys[cpuacct_subsys_id] = &ca->css;
+       return 0;
+}
+
+static void cpuacct_destroy(struct container_subsys *ss,
+                           struct container *cont)
+{
+       kfree(container_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 container *cont,
+                        struct cftype *cft)
+{
+       struct cpuacct *ca = container_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 container *cont,
+                    struct cftype *cft)
+{
+       struct cpuacct *ca = container_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 = "cpuacct.usage",
+               .read_uint = cpuusage_read,
+       },
+       {
+               .name = "cpuacct.load",
+               .read_uint = load_read,
+       }
+};
+
+static int cpuacct_populate(struct container_subsys *ss,
+                           struct container *cont)
+{
+       return container_add_files(cont, 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 container_subsys cpuacct_subsys = {
+       .name = "cpuacct",
+       .create = cpuacct_create,
+       .destroy = cpuacct_destroy,
+       .populate = cpuacct_populate,
+       .subsys_id = cpuacct_subsys_id,
+};
Index: container-2.6.22-rc2-mm1/kernel/sched.c
===================================================================
--- container-2.6.22-rc2-mm1.orig/kernel/sched.c
+++ container-2.6.22-rc2-mm1/kernel/sched.c
@@ -59,6 +59,7 @@
 #include <linux/kprobes.h>
 #include <linux/delayacct.h>
 #include <linux/reciprocal_div.h>
+#include <linux/cpu_acct.h>
 
 #include <asm/tlb.h>
 #include <asm/unistd.h>
@@ -2847,9 +2848,13 @@ void account_user_time(struct task_struc
 {
        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)
@@ -2879,9 +2884,10 @@ void account_system_time(struct task_str
                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);
-       else if (atomic_read(&rq->nr_iowait) > 0)
+               cpuacct_charge(p, cputime);
+       } else if (atomic_read(&rq->nr_iowait) > 0)
                cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
        else
                cpustat->idle = cputime64_add(cpustat->idle, tmp);
@@ -2906,8 +2912,10 @@ void account_steal_time(struct task_stru
                        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);
+       }
 }
 
 /*

--

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