This implements a couple of basic statistics for the CPU resource controller.
v2->v3
-------
Proper locking while collecting stats. Thanks to Peter Zijlstra for suggesting
the delta approach.
This applies against 2.6.25-mm1
---
Signed-off-by: Balaji Rao <[EMAIL PROTECTED]>
diff --git a/kernel/sched.c b/kernel/sched.c
index bbdc32a..5bda75a 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -248,10 +248,51 @@ struct cfs_rq;
static LIST_HEAD(task_groups);
+#ifdef CONFIG_CGROUP_SCHED
+
+#define CPU_CGROUP_STAT_THRESHOLD 1 << 30
+
+enum cpu_cgroup_stat_index {
+ CPU_CGROUP_STAT_UTIME, /* Usertime of the task group */
+ CPU_CGROUP_STAT_STIME, /* Kerneltime of the task group */
+
+ CPU_CGROUP_STAT_NSTATS,
+};
+
+struct cpu_cgroup_stat_cpu {
+ s64 count[CPU_CGROUP_STAT_NSTATS];
+ u32 delta[CPU_CGROUP_STAT_NSTATS];
+} ____cacheline_aligned_in_smp;
+
+struct cpu_cgroup_stat {
+ struct cpu_cgroup_stat_cpu cpustat[NR_CPUS];
+ spinlock_t lock;
+};
+
+/* Called under irq disable. */
+static void __cpu_cgroup_stat_add(struct cpu_cgroup_stat *stat,
+ enum cpu_cgroup_stat_index idx, int val)
+{
+ int cpu = smp_processor_id();
+ unsigned long flags;
+
+ BUG_ON(!irqs_disabled());
+ stat->cpustat[cpu].delta[idx] += val;
+
+ if (stat->cpustat[cpu].delta[idx] > CPU_CGROUP_STAT_THRESHOLD) {
+ spin_lock_irqsave(&stat->lock, flags);
+ stat->cpustat[cpu].count[idx] += stat->cpustat[cpu].delta[idx];
+ stat->cpustat[cpu].delta[idx] = 0;
+ spin_unlock_irqrestore(&stat->lock, flags);
+ }
+}
+#endif
+
/* task group related information */
struct task_group {
#ifdef CONFIG_CGROUP_SCHED
struct cgroup_subsys_state css;
+ struct cpu_cgroup_stat stat;
#endif
#ifdef CONFIG_FAIR_GROUP_SCHED
@@ -3837,6 +3878,16 @@ void account_user_time(struct task_struct *p, cputime_t
cputime)
cpustat->nice = cputime64_add(cpustat->nice, tmp);
else
cpustat->user = cputime64_add(cpustat->user, tmp);
+
+ /* Charge the task's group */
+#ifdef CONFIG_CGROUP_SCHED
+ {
+ struct task_group *tg;
+ tg = task_group(p);
+ __cpu_cgroup_stat_add(&tg->stat, CPU_CGROUP_STAT_UTIME,
+ cputime_to_msecs(cputime));
+ }
+#endif
}
/*
@@ -3900,6 +3951,15 @@ void account_system_time(struct task_struct *p, int
hardirq_offset,
cpustat->idle = cputime64_add(cpustat->idle, tmp);
/* Account for system time used */
acct_update_integrals(p);
+
+#ifdef CONFIG_CGROUP_SCHED
+ {
+ struct task_group *tg;
+ tg = task_group(p);
+ __cpu_cgroup_stat_add(&tg->stat, CPU_CGROUP_STAT_STIME,
+ cputime_to_msecs(cputime));
+ }
+#endif
}
/*
@@ -7838,7 +7898,9 @@ struct task_group *sched_create_group(void)
}
list_add_rcu(&tg->list, &task_groups);
spin_unlock_irqrestore(&task_group_lock, flags);
-
+#ifdef CONFIG_CGROUP_SCHED
+ spin_lock_init(&tg->stat.lock);
+#endif
return tg;
err:
@@ -8249,6 +8311,48 @@ static u64 cpu_shares_read_u64(struct cgroup *cgrp,
struct cftype *cft)
return (u64) tg->shares;
}
+
+static s64 cpu_cgroup_read_stat(struct cpu_cgroup_stat *stat,
+ enum cpu_cgroup_stat_index idx)
+{
+ int cpu;
+ s64 ret = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&stat->lock, flags);
+ for_each_possible_cpu(cpu) {
+ stat->cpustat[cpu].count[idx] += stat->cpustat[cpu].delta[idx];
+ stat->cpustat[cpu].delta[idx] = 0;
+ ret += stat->cpustat[cpu].count[idx];
+ }
+ spin_unlock_irqrestore(&stat->lock, flags);
+
+ return ret;
+}
+
+static const struct cpu_cgroup_stat_desc {
+ const char *msg;
+ u64 unit;
+} cpu_cgroup_stat_desc[] = {
+ [CPU_CGROUP_STAT_UTIME] = { "utime", 1, },
+ [CPU_CGROUP_STAT_STIME] = { "stime", 1, },
+};
+
+static int cpu_cgroup_stats_show(struct cgroup *cgrp, struct cftype *cft,
+ struct cgroup_map_cb *cb)
+{
+ struct task_group *tg = cgroup_tg(cgrp);
+ struct cpu_cgroup_stat *stat = &tg->stat;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(stat->cpustat[0].count); i++) {
+ s64 val;
+ val = cpu_cgroup_read_stat(stat, i);
+ val *= cpu_cgroup_stat_desc[i].unit;
+ cb->fill(cb, cpu_cgroup_stat_desc[i].msg, val);
+ }
+ return 0;
+}
#endif
#ifdef CONFIG_RT_GROUP_SCHED
@@ -8295,6 +8399,10 @@ static struct cftype cpu_files[] = {
.write_u64 = cpu_rt_period_write_uint,
},
#endif
+ {
+ .name = "stat",
+ .read_map = cpu_cgroup_stats_show,
+ },
};
static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
--
Warm Regards,
Balaji Rao
Dept. of Mechanical Engineering
NITK
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