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Message-Id: <1235559850.4645.3210.camel@laptop>
Date: Wed, 25 Feb 2009 12:04:10 +0100
From: Peter Zijlstra <a.p.zijlstra@...llo.nl>
To: bharata@...ux.vnet.ibm.com
Cc: linux-kernel@...r.kernel.org, Balaji Rao <balajirrao@...il.com>,
Dhaval Giani <dhaval@...ux.vnet.ibm.com>,
Balbir Singh <balbir@...ux.vnet.ibm.com>,
Li Zefan <lizf@...fujitsu.com>,
Paul Menage <menage@...gle.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Ingo Molnar <mingo@...e.hu>
Subject: Re: [RFC PATCH 2/2] Add per-cgroup CPU controller statistics
On Wed, 2009-02-25 at 16:29 +0530, Bharata B Rao wrote:
> From: Balaji Rao <balajirrao@...il.com>
>
> sched: Add cpu controller statistics
>
> Add per-cgroup cpu controller statistics like system time and user time
> consumed by groups of tasks.
Do we want this unconditionally?
> Signed-off-by: Balaji Rao <balajirrao@...il.com>
> Signed-off-by: Bharata B Rao <bharata@...ux.vnet.ibm.com>
> ---
> kernel/sched.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 106 insertions(+)
>
> --- a/kernel/sched.c
> +++ b/kernel/sched.c
> @@ -263,10 +263,25 @@ struct cfs_rq;
>
> static LIST_HEAD(task_groups);
>
> +#ifdef CONFIG_CGROUP_SCHED
> +enum cpu_cgroup_stat_index {
> + CPU_CGROUP_STAT_UTIME, /* User time of the task group */
> + CPU_CGROUP_STAT_STIME, /* Kernel time of the task group */
> + CPU_CGROUP_STAT_GTIME, /* Guest time of the task group */
> +
> + CPU_CGROUP_STAT_NSTATS,
> +};
> +
> +struct cpu_cgroup_stat {
> + struct percpu_counter cpustat[CPU_CGROUP_STAT_NSTATS];
> +};
> +#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_USER_SCHED
> @@ -4159,6 +4174,19 @@ unsigned long long task_delta_exec(struc
> return ns;
> }
>
> +#ifdef CONFIG_CGROUP_SCHED
> +static void account_task_group_time(struct task_struct *p,
> + enum cpu_cgroup_stat_index idx, int val)
> +{
> + struct task_group *tg = task_group(p);
> +
> + if (likely(tg->stat))
> + percpu_counter_add(&tg->stat->cpustat[idx], val);
> +}
> +#else
> +#define account_task_group_time(x, y, z) { 0; }
inline please, so we get argument validation.
> +#endif
> +
> /*
> * Account user cpu time to a process.
> * @p: the process that the cpu time gets accounted to
> @@ -4182,6 +4210,10 @@ void account_user_time(struct task_struc
> cpustat->nice = cputime64_add(cpustat->nice, tmp);
> else
> cpustat->user = cputime64_add(cpustat->user, tmp);
> +
> + account_task_group_time(p, CPU_CGROUP_STAT_UTIME,
> + cputime_to_msecs(cputime));
> +
> /* Account for user time used */
> acct_update_integrals(p);
> }
> @@ -4206,6 +4238,9 @@ static void account_guest_time(struct ta
> account_group_user_time(p, cputime);
> p->gtime = cputime_add(p->gtime, cputime);
>
> + account_task_group_time(p, CPU_CGROUP_STAT_GTIME,
> + cputime_to_msecs(cputime));
> +
> /* Add guest time to cpustat. */
> cpustat->user = cputime64_add(cpustat->user, tmp);
> cpustat->guest = cputime64_add(cpustat->guest, tmp);
> @@ -4243,6 +4278,8 @@ void account_system_time(struct task_str
> else
> cpustat->system = cputime64_add(cpustat->system, tmp);
>
> + account_task_group_time(p, CPU_CGROUP_STAT_STIME,
> + cputime_to_msecs(cputime));
> /* Account for system time used */
> acct_update_integrals(p);
> }
> @@ -9290,6 +9327,7 @@ static struct cgroup_subsys_state *
> cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
> {
> struct task_group *tg, *parent;
> + int i;
>
> if (!cgrp->parent) {
> /* This is early initialization for the top cgroup */
> @@ -9301,6 +9339,15 @@ cpu_cgroup_create(struct cgroup_subsys *
> if (IS_ERR(tg))
> return ERR_PTR(-ENOMEM);
>
> + tg->stat = kmalloc(sizeof(struct cpu_cgroup_stat), GFP_KERNEL);
> + if (!tg->stat) {
> + sched_destroy_group(tg);
> + return ERR_PTR(-ENOMEM);
> + }
> +
> + for (i = 0; i < CPU_CGROUP_STAT_NSTATS; i++)
> + percpu_counter_init(&tg->stat->cpustat[i], 0);
percpu_counter_init() can fail with -ENOMEM.
> return &tg->css;
> }
>
> @@ -9308,6 +9355,13 @@ static void
> cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
> {
> struct task_group *tg = cgroup_tg(cgrp);
> + int i;
> +
> + if (tg->stat) {
> + for (i = 0; i < CPU_CGROUP_STAT_NSTATS; i++)
> + percpu_counter_destroy(&tg->stat->cpustat[i]);
> + kfree(tg->stat);
> + }
>
> sched_destroy_group(tg);
> }
> @@ -9336,6 +9390,53 @@ cpu_cgroup_attach(struct cgroup_subsys *
> sched_move_task(tsk);
> }
>
> +static void cpu_cgroup_initialize(void)
> +{
> + int i;
> + struct cpu_cgroup_stat *stat;
> +
> + stat = kmalloc(sizeof(struct cpu_cgroup_stat) , GFP_KERNEL);
> + if (!stat)
> + return;
> +
> + for (i = 0; i < CPU_CGROUP_STAT_NSTATS; i++)
> + percpu_counter_init(&stat->cpustat[i], 0);
> + init_task_group.stat = stat;
> +}
> +
> +static s64 cpu_cgroup_read_stat(struct cpu_cgroup_stat *stat,
> + enum cpu_cgroup_stat_index idx)
> +{
> + if (stat)
> + return percpu_counter_read(&stat->cpustat[idx]);
> + return 0;
> +}
> +
> +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, },
> + [CPU_CGROUP_STAT_GTIME] = { "gtime", 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 < CPU_CGROUP_STAT_NSTATS; 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;
> +}
> +
> #ifdef CONFIG_FAIR_GROUP_SCHED
> static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
> u64 shareval)
> @@ -9395,6 +9496,10 @@ 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)
> @@ -9409,6 +9514,7 @@ struct cgroup_subsys cpu_cgroup_subsys =
> .can_attach = cpu_cgroup_can_attach,
> .attach = cpu_cgroup_attach,
> .populate = cpu_cgroup_populate,
> + .initialize = cpu_cgroup_initialize,
> .subsys_id = cpu_cgroup_subsys_id,
> .early_init = 1,
> };
--
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