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Subject[RFD 1/9] Change cpustat fields to an array.
Date
This will give us a bit more flexibility to deal with the
fields in this structure. This is a preparation patch for
later patches in this series.

I tried to keep the acessor macros unchanged, so we don't need
to patch all users.. At some point I gave up on kstat_this_cpu.
But to be fair, this one is not used outside of sched.c, so is
not a big deal.

Signed-off-by: Glauber Costa <glommer@parallels.com>
---
fs/proc/stat.c | 40 ++++++++++++------------
fs/proc/uptime.c | 2 +-
include/linux/kernel_stat.h | 46 +++++++++++++++++-----------
kernel/sched.c | 68 ++++++++++++++++++++++++-------------------
4 files changed, 87 insertions(+), 69 deletions(-)
diff --git a/fs/proc/stat.c b/fs/proc/stat.c
index 9758b65..ec708c7 100644
--- a/fs/proc/stat.c
+++ b/fs/proc/stat.c
@@ -39,18 +39,18 @@ static int show_stat(struct seq_file *p, void *v)
jif = boottime.tv_sec;

for_each_possible_cpu(i) {
- user = cputime64_add(user, kstat_cpu(i).cpustat.user);
- nice = cputime64_add(nice, kstat_cpu(i).cpustat.nice);
- system = cputime64_add(system, kstat_cpu(i).cpustat.system);
- idle = cputime64_add(idle, kstat_cpu(i).cpustat.idle);
+ user = cputime64_add(user, kstat_cpu(i).cpustat[USER]);
+ nice = cputime64_add(nice, kstat_cpu(i).cpustat[NICE]);
+ system = cputime64_add(system, kstat_cpu(i).cpustat[SYSTEM]);
+ idle = cputime64_add(idle, kstat_cpu(i).cpustat[IDLE]);
idle = cputime64_add(idle, arch_idle_time(i));
- iowait = cputime64_add(iowait, kstat_cpu(i).cpustat.iowait);
- irq = cputime64_add(irq, kstat_cpu(i).cpustat.irq);
- softirq = cputime64_add(softirq, kstat_cpu(i).cpustat.softirq);
- steal = cputime64_add(steal, kstat_cpu(i).cpustat.steal);
- guest = cputime64_add(guest, kstat_cpu(i).cpustat.guest);
+ iowait = cputime64_add(iowait, kstat_cpu(i).cpustat[IOWAIT]);
+ irq = cputime64_add(irq, kstat_cpu(i).cpustat[IRQ]);
+ softirq = cputime64_add(softirq, kstat_cpu(i).cpustat[SOFTIRQ]);
+ steal = cputime64_add(steal, kstat_cpu(i).cpustat[STEAL]);
+ guest = cputime64_add(guest, kstat_cpu(i).cpustat[GUEST]);
guest_nice = cputime64_add(guest_nice,
- kstat_cpu(i).cpustat.guest_nice);
+ kstat_cpu(i).cpustat[GUEST_NICE]);
sum += kstat_cpu_irqs_sum(i);
sum += arch_irq_stat_cpu(i);

@@ -78,17 +78,17 @@ static int show_stat(struct seq_file *p, void *v)
for_each_online_cpu(i) {

/* Copy values here to work around gcc-2.95.3, gcc-2.96 */
- user = kstat_cpu(i).cpustat.user;
- nice = kstat_cpu(i).cpustat.nice;
- system = kstat_cpu(i).cpustat.system;
- idle = kstat_cpu(i).cpustat.idle;
+ user = kstat_cpu(i).cpustat[USER];
+ nice = kstat_cpu(i).cpustat[NICE];
+ system = kstat_cpu(i).cpustat[SYSTEM];
+ idle = kstat_cpu(i).cpustat[IDLE];
idle = cputime64_add(idle, arch_idle_time(i));
- iowait = kstat_cpu(i).cpustat.iowait;
- irq = kstat_cpu(i).cpustat.irq;
- softirq = kstat_cpu(i).cpustat.softirq;
- steal = kstat_cpu(i).cpustat.steal;
- guest = kstat_cpu(i).cpustat.guest;
- guest_nice = kstat_cpu(i).cpustat.guest_nice;
+ iowait = kstat_cpu(i).cpustat[IOWAIT];
+ irq = kstat_cpu(i).cpustat[IRQ];
+ softirq = kstat_cpu(i).cpustat[SOFTIRQ];
+ steal = kstat_cpu(i).cpustat[STEAL];
+ guest = kstat_cpu(i).cpustat[GUEST];
+ guest_nice = kstat_cpu(i).cpustat[GUEST_NICE];
seq_printf(p,
"cpu%d %llu %llu %llu %llu %llu %llu %llu %llu %llu "
"%llu\n",
diff --git a/fs/proc/uptime.c b/fs/proc/uptime.c
index 766b1d4..b0e053d 100644
--- a/fs/proc/uptime.c
+++ b/fs/proc/uptime.c
@@ -15,7 +15,7 @@ static int uptime_proc_show(struct seq_file *m, void *v)
cputime_t idletime = cputime_zero;

for_each_possible_cpu(i)
- idletime = cputime64_add(idletime, kstat_cpu(i).cpustat.idle);
+ idletime = cputime64_add(idletime, kstat_cpu(i).cpustat[IDLE]);

do_posix_clock_monotonic_gettime(&uptime);
monotonic_to_bootbased(&uptime);
diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index 0cce2db..93f64f3 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -6,6 +6,7 @@
#include <linux/percpu.h>
#include <linux/cpumask.h>
#include <linux/interrupt.h>
+#include <linux/sched.h>
#include <asm/irq.h>
#include <asm/cputime.h>

@@ -15,21 +16,22 @@
* used by rstatd/perfmeter
*/

-struct cpu_usage_stat {
- cputime64_t user;
- cputime64_t nice;
- cputime64_t system;
- cputime64_t softirq;
- cputime64_t irq;
- cputime64_t idle;
- cputime64_t iowait;
- cputime64_t steal;
- cputime64_t guest;
- cputime64_t guest_nice;
+enum cpu_usage_stat {
+ USER,
+ NICE,
+ SYSTEM,
+ SOFTIRQ,
+ IRQ,
+ IDLE,
+ IOWAIT,
+ STEAL,
+ GUEST,
+ GUEST_NICE,
+ NR_STATS,
};

struct kernel_stat {
- struct cpu_usage_stat cpustat;
+ cputime64_t cpustat[NR_STATS];
#ifndef CONFIG_GENERIC_HARDIRQS
unsigned int irqs[NR_IRQS];
#endif
@@ -39,9 +41,17 @@ struct kernel_stat {

DECLARE_PER_CPU(struct kernel_stat, kstat);

-#define kstat_cpu(cpu) per_cpu(kstat, cpu)
+struct kernel_stat *task_group_kstat(struct task_struct *p);
+
+#ifdef CONFIG_CGROUP_SCHED
+#define kstat_cpu(cpu) (*per_cpu_ptr(task_group_kstat(current), cpu))
+
/* Must have preemption disabled for this to be meaningful. */
-#define kstat_this_cpu __get_cpu_var(kstat)
+#define kstat_this_cpu this_cpu_ptr(task_group_kstat(current))
+#else
+#define kstat_cpu(cpu) per_cpu(kstat, cpu)
+#define kstat_this_cpu (&__get_cpu_var(kstat))
+#endif

extern unsigned long long nr_context_switches(void);

@@ -52,8 +62,8 @@ struct irq_desc;
static inline void kstat_incr_irqs_this_cpu(unsigned int irq,
struct irq_desc *desc)
{
- __this_cpu_inc(kstat.irqs[irq]);
- __this_cpu_inc(kstat.irqs_sum);
+ kstat_this_cpu->irqs[irq]++;
+ kstat_this_cpu->irqs_sum++;
}

static inline unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
@@ -67,14 +77,14 @@ extern unsigned int kstat_irqs_cpu(unsigned int irq, int cpu);
#define kstat_incr_irqs_this_cpu(irqno, DESC) \
do { \
__this_cpu_inc(*(DESC)->kstat_irqs); \
- __this_cpu_inc(kstat.irqs_sum); \
+ kstat_this_cpu->irqs_sum++; \
} while (0)

#endif

static inline void kstat_incr_softirqs_this_cpu(unsigned int irq)
{
- __this_cpu_inc(kstat.softirqs[irq]);
+ kstat_this_cpu->softirqs[irq]++;
}

static inline unsigned int kstat_softirqs_cpu(unsigned int irq, int cpu)
diff --git a/kernel/sched.c b/kernel/sched.c
index 3ed4107..2f6bab4 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -278,6 +278,7 @@ struct task_group {
#ifdef CONFIG_SCHED_AUTOGROUP
struct autogroup *autogroup;
#endif
+ struct kernel_stat __percpu *cpustat;
};

/* task_group_lock serializes the addition/removal of task groups */
@@ -623,6 +624,9 @@ static inline struct task_group *task_group(struct task_struct *p)
struct task_group *tg;
struct cgroup_subsys_state *css;

+ if (!p->mm)
+ return &root_task_group;
+
css = task_subsys_state_check(p, cpu_cgroup_subsys_id,
lockdep_is_held(&p->pi_lock) ||
lockdep_is_held(&task_rq(p)->lock));
@@ -631,6 +635,12 @@ static inline struct task_group *task_group(struct task_struct *p)
return autogroup_task_group(p, tg);
}

+struct kernel_stat *task_group_kstat(struct task_struct *p)
+{
+ struct task_group *tg = task_group(p);
+
+ return tg->cpustat;
+}
/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
{
@@ -653,6 +663,8 @@ static inline struct task_group *task_group(struct task_struct *p)
return NULL;
}

+DEFINE_PER_CPU(struct kernel_stat, kstat);
+EXPORT_PER_CPU_SYMBOL(kstat);
#endif /* CONFIG_CGROUP_SCHED */

static void update_rq_clock_task(struct rq *rq, s64 delta);
@@ -2004,14 +2016,14 @@ static void update_rq_clock_task(struct rq *rq, s64 delta)
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
static int irqtime_account_hi_update(void)
{
- struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+ cputime64_t *cpustat = kstat_this_cpu->cpustat;
unsigned long flags;
u64 latest_ns;
int ret = 0;

local_irq_save(flags);
latest_ns = this_cpu_read(cpu_hardirq_time);
- if (cputime64_gt(nsecs_to_cputime64(latest_ns), cpustat->irq))
+ if (cputime64_gt(nsecs_to_cputime64(latest_ns), cpustat[IRQ]))
ret = 1;
local_irq_restore(flags);
return ret;
@@ -2019,14 +2031,14 @@ static int irqtime_account_hi_update(void)

static int irqtime_account_si_update(void)
{
- struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+ cputime64_t *cpustat = kstat_this_cpu->cpustat;
unsigned long flags;
u64 latest_ns;
int ret = 0;

local_irq_save(flags);
latest_ns = this_cpu_read(cpu_softirq_time);
- if (cputime64_gt(nsecs_to_cputime64(latest_ns), cpustat->softirq))
+ if (cputime64_gt(nsecs_to_cputime64(latest_ns), cpustat[SOFTIRQ]))
ret = 1;
local_irq_restore(flags);
return ret;
@@ -3669,10 +3681,6 @@ unlock:

#endif

-DEFINE_PER_CPU(struct kernel_stat, kstat);
-
-EXPORT_PER_CPU_SYMBOL(kstat);
-
/*
* Return any ns on the sched_clock that have not yet been accounted in
* @p in case that task is currently running.
@@ -3757,7 +3765,7 @@ unsigned long long thread_group_sched_runtime(struct task_struct *p)
void account_user_time(struct task_struct *p, cputime_t cputime,
cputime_t cputime_scaled)
{
- struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+ cputime64_t *cpustat = kstat_this_cpu->cpustat;
cputime64_t tmp;

/* Add user time to process. */
@@ -3768,9 +3776,9 @@ void account_user_time(struct task_struct *p, cputime_t cputime,
/* Add user time to cpustat. */
tmp = cputime_to_cputime64(cputime);
if (TASK_NICE(p) > 0)
- cpustat->nice = cputime64_add(cpustat->nice, tmp);
+ cpustat[NICE] = cputime64_add(cpustat[NICE], tmp);
else
- cpustat->user = cputime64_add(cpustat->user, tmp);
+ cpustat[USER] = cputime64_add(cpustat[USER], tmp);

cpuacct_update_stats(p, CPUACCT_STAT_USER, cputime);
/* Account for user time used */
@@ -3787,7 +3795,7 @@ static void account_guest_time(struct task_struct *p, cputime_t cputime,
cputime_t cputime_scaled)
{
cputime64_t tmp;
- struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+ cputime64_t *cpustat = kstat_this_cpu->cpustat;

tmp = cputime_to_cputime64(cputime);

@@ -3799,11 +3807,11 @@ static void account_guest_time(struct task_struct *p, cputime_t cputime,

/* Add guest time to cpustat. */
if (TASK_NICE(p) > 0) {
- cpustat->nice = cputime64_add(cpustat->nice, tmp);
- cpustat->guest_nice = cputime64_add(cpustat->guest_nice, tmp);
+ cpustat[NICE] = cputime64_add(cpustat[NICE], tmp);
+ cpustat[GUEST_NICE] = cputime64_add(cpustat[GUEST_NICE], tmp);
} else {
- cpustat->user = cputime64_add(cpustat->user, tmp);
- cpustat->guest = cputime64_add(cpustat->guest, tmp);
+ cpustat[USER] = cputime64_add(cpustat[USER], tmp);
+ cpustat[GUEST] = cputime64_add(cpustat[GUEST], tmp);
}
}

@@ -3843,7 +3851,7 @@ void __account_system_time(struct task_struct *p, cputime_t cputime,
void account_system_time(struct task_struct *p, int hardirq_offset,
cputime_t cputime, cputime_t cputime_scaled)
{
- struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+ cputime64_t *cpustat = kstat_this_cpu->cpustat;
cputime64_t *target_cputime64;

if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
@@ -3852,11 +3860,11 @@ void account_system_time(struct task_struct *p, int hardirq_offset,
}

if (hardirq_count() - hardirq_offset)
- target_cputime64 = &cpustat->irq;
+ target_cputime64 = &cpustat[IRQ];
else if (in_serving_softirq())
- target_cputime64 = &cpustat->softirq;
+ target_cputime64 = &cpustat[SOFTIRQ];
else
- target_cputime64 = &cpustat->system;
+ target_cputime64 = &cpustat[SYSTEM];

__account_system_time(p, cputime, cputime_scaled, target_cputime64);
}
@@ -3867,10 +3875,10 @@ void account_system_time(struct task_struct *p, int hardirq_offset,
*/
void account_steal_time(cputime_t cputime)
{
- struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+ cputime64_t *cpustat = kstat_this_cpu->cpustat;
cputime64_t cputime64 = cputime_to_cputime64(cputime);

- cpustat->steal = cputime64_add(cpustat->steal, cputime64);
+ cpustat[STEAL] = cputime64_add(cpustat[STEAL], cputime64);
}

/*
@@ -3879,14 +3887,14 @@ void account_steal_time(cputime_t cputime)
*/
void account_idle_time(cputime_t cputime)
{
- struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+ cputime64_t *cpustat = kstat_this_cpu->cpustat;
cputime64_t cputime64 = cputime_to_cputime64(cputime);
struct rq *rq = this_rq();

if (atomic_read(&rq->nr_iowait) > 0)
- cpustat->iowait = cputime64_add(cpustat->iowait, cputime64);
+ cpustat[IOWAIT] = cputime64_add(cpustat[IOWAIT], cputime64);
else
- cpustat->idle = cputime64_add(cpustat->idle, cputime64);
+ cpustat[IDLE] = cputime64_add(cpustat[IDLE], cputime64);
}

static __always_inline bool steal_account_process_tick(void)
@@ -3937,15 +3945,15 @@ static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
{
cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
cputime64_t tmp = cputime_to_cputime64(cputime_one_jiffy);
- struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+ cputime64_t *cpustat = kstat_this_cpu->cpustat;

if (steal_account_process_tick())
return;

if (irqtime_account_hi_update()) {
- cpustat->irq = cputime64_add(cpustat->irq, tmp);
+ cpustat[IRQ] = cputime64_add(cpustat[IRQ], tmp);
} else if (irqtime_account_si_update()) {
- cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
+ cpustat[SOFTIRQ] = cputime64_add(cpustat[SOFTIRQ], tmp);
} else if (this_cpu_ksoftirqd() == p) {
/*
* ksoftirqd time do not get accounted in cpu_softirq_time.
@@ -3953,7 +3961,7 @@ static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
* Also, p->stime needs to be updated for ksoftirqd.
*/
__account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
- &cpustat->softirq);
+ &cpustat[SOFTIRQ]);
} else if (user_tick) {
account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
} else if (p == rq->idle) {
@@ -3962,7 +3970,7 @@ static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled);
} else {
__account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
- &cpustat->system);
+ &cpustat[SYSTEM]);
}
}

--
1.7.6


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