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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 09:19:51 +00:00
![Frederic Weisbecker](/assets/img/avatar_default.png)
Kernel CPU stats are stored in cputime_t which is an architecture defined type, and hence a bit opaque and requiring accessors and mutators for any operation. Converting them to nsecs simplifies the code and is one step toward the removal of cputime_t in the core code. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Link: http://lkml.kernel.org/r/1485832191-26889-4-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
385 lines
8.3 KiB
C
385 lines
8.3 KiB
C
#include <linux/cgroup.h>
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#include <linux/slab.h>
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#include <linux/percpu.h>
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#include <linux/spinlock.h>
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#include <linux/cpumask.h>
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#include <linux/seq_file.h>
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#include <linux/rcupdate.h>
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#include <linux/kernel_stat.h>
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#include <linux/err.h>
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#include "sched.h"
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/*
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* CPU accounting code for task groups.
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*
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* Based on the work by Paul Menage (menage@google.com) and Balbir Singh
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* (balbir@in.ibm.com).
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*/
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/* Time spent by the tasks of the cpu accounting group executing in ... */
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enum cpuacct_stat_index {
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CPUACCT_STAT_USER, /* ... user mode */
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CPUACCT_STAT_SYSTEM, /* ... kernel mode */
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CPUACCT_STAT_NSTATS,
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};
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static const char * const cpuacct_stat_desc[] = {
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[CPUACCT_STAT_USER] = "user",
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[CPUACCT_STAT_SYSTEM] = "system",
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};
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struct cpuacct_usage {
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u64 usages[CPUACCT_STAT_NSTATS];
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};
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/* track cpu usage of a group of tasks and its child groups */
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struct cpuacct {
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struct cgroup_subsys_state css;
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/* cpuusage holds pointer to a u64-type object on every cpu */
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struct cpuacct_usage __percpu *cpuusage;
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struct kernel_cpustat __percpu *cpustat;
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};
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static inline struct cpuacct *css_ca(struct cgroup_subsys_state *css)
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{
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return css ? container_of(css, struct cpuacct, css) : NULL;
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}
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/* return cpu accounting group to which this task belongs */
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static inline struct cpuacct *task_ca(struct task_struct *tsk)
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{
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return css_ca(task_css(tsk, cpuacct_cgrp_id));
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}
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static inline struct cpuacct *parent_ca(struct cpuacct *ca)
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{
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return css_ca(ca->css.parent);
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}
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static DEFINE_PER_CPU(struct cpuacct_usage, root_cpuacct_cpuusage);
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static struct cpuacct root_cpuacct = {
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.cpustat = &kernel_cpustat,
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.cpuusage = &root_cpuacct_cpuusage,
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};
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/* create a new cpu accounting group */
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static struct cgroup_subsys_state *
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cpuacct_css_alloc(struct cgroup_subsys_state *parent_css)
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{
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struct cpuacct *ca;
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if (!parent_css)
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return &root_cpuacct.css;
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ca = kzalloc(sizeof(*ca), GFP_KERNEL);
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if (!ca)
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goto out;
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ca->cpuusage = alloc_percpu(struct cpuacct_usage);
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if (!ca->cpuusage)
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goto out_free_ca;
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ca->cpustat = alloc_percpu(struct kernel_cpustat);
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if (!ca->cpustat)
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goto out_free_cpuusage;
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return &ca->css;
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out_free_cpuusage:
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free_percpu(ca->cpuusage);
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out_free_ca:
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kfree(ca);
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out:
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return ERR_PTR(-ENOMEM);
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}
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/* destroy an existing cpu accounting group */
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static void cpuacct_css_free(struct cgroup_subsys_state *css)
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{
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struct cpuacct *ca = css_ca(css);
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free_percpu(ca->cpustat);
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free_percpu(ca->cpuusage);
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kfree(ca);
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}
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static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu,
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enum cpuacct_stat_index index)
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{
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struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
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u64 data;
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/*
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* We allow index == CPUACCT_STAT_NSTATS here to read
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* the sum of suages.
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*/
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BUG_ON(index > CPUACCT_STAT_NSTATS);
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#ifndef CONFIG_64BIT
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/*
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* Take rq->lock to make 64-bit read safe on 32-bit platforms.
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*/
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raw_spin_lock_irq(&cpu_rq(cpu)->lock);
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#endif
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if (index == CPUACCT_STAT_NSTATS) {
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int i = 0;
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data = 0;
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for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
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data += cpuusage->usages[i];
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} else {
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data = cpuusage->usages[index];
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}
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#ifndef CONFIG_64BIT
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raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
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#endif
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return data;
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}
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static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
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{
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struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
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int i;
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#ifndef CONFIG_64BIT
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/*
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* Take rq->lock to make 64-bit write safe on 32-bit platforms.
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*/
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raw_spin_lock_irq(&cpu_rq(cpu)->lock);
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#endif
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for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
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cpuusage->usages[i] = val;
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#ifndef CONFIG_64BIT
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raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
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#endif
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}
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/* return total cpu usage (in nanoseconds) of a group */
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static u64 __cpuusage_read(struct cgroup_subsys_state *css,
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enum cpuacct_stat_index index)
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{
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struct cpuacct *ca = css_ca(css);
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u64 totalcpuusage = 0;
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int i;
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for_each_possible_cpu(i)
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totalcpuusage += cpuacct_cpuusage_read(ca, i, index);
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return totalcpuusage;
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}
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static u64 cpuusage_user_read(struct cgroup_subsys_state *css,
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struct cftype *cft)
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{
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return __cpuusage_read(css, CPUACCT_STAT_USER);
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}
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static u64 cpuusage_sys_read(struct cgroup_subsys_state *css,
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struct cftype *cft)
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{
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return __cpuusage_read(css, CPUACCT_STAT_SYSTEM);
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}
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static u64 cpuusage_read(struct cgroup_subsys_state *css, struct cftype *cft)
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{
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return __cpuusage_read(css, CPUACCT_STAT_NSTATS);
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}
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static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft,
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u64 val)
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{
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struct cpuacct *ca = css_ca(css);
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int cpu;
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/*
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* Only allow '0' here to do a reset.
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*/
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if (val)
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return -EINVAL;
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for_each_possible_cpu(cpu)
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cpuacct_cpuusage_write(ca, cpu, 0);
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return 0;
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}
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static int __cpuacct_percpu_seq_show(struct seq_file *m,
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enum cpuacct_stat_index index)
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{
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struct cpuacct *ca = css_ca(seq_css(m));
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u64 percpu;
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int i;
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for_each_possible_cpu(i) {
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percpu = cpuacct_cpuusage_read(ca, i, index);
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seq_printf(m, "%llu ", (unsigned long long) percpu);
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}
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seq_printf(m, "\n");
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return 0;
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}
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static int cpuacct_percpu_user_seq_show(struct seq_file *m, void *V)
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{
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return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_USER);
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}
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static int cpuacct_percpu_sys_seq_show(struct seq_file *m, void *V)
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{
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return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_SYSTEM);
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}
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static int cpuacct_percpu_seq_show(struct seq_file *m, void *V)
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{
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return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_NSTATS);
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}
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static int cpuacct_all_seq_show(struct seq_file *m, void *V)
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{
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struct cpuacct *ca = css_ca(seq_css(m));
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int index;
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int cpu;
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seq_puts(m, "cpu");
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for (index = 0; index < CPUACCT_STAT_NSTATS; index++)
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seq_printf(m, " %s", cpuacct_stat_desc[index]);
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seq_puts(m, "\n");
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for_each_possible_cpu(cpu) {
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struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
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seq_printf(m, "%d", cpu);
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for (index = 0; index < CPUACCT_STAT_NSTATS; index++) {
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#ifndef CONFIG_64BIT
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/*
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* Take rq->lock to make 64-bit read safe on 32-bit
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* platforms.
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*/
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raw_spin_lock_irq(&cpu_rq(cpu)->lock);
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#endif
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seq_printf(m, " %llu", cpuusage->usages[index]);
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#ifndef CONFIG_64BIT
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raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
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#endif
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}
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seq_puts(m, "\n");
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}
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return 0;
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}
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static int cpuacct_stats_show(struct seq_file *sf, void *v)
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{
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struct cpuacct *ca = css_ca(seq_css(sf));
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s64 val[CPUACCT_STAT_NSTATS];
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int cpu;
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int stat;
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memset(val, 0, sizeof(val));
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for_each_possible_cpu(cpu) {
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u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
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val[CPUACCT_STAT_USER] += cpustat[CPUTIME_USER];
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val[CPUACCT_STAT_USER] += cpustat[CPUTIME_NICE];
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val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SYSTEM];
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val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_IRQ];
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val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SOFTIRQ];
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}
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for (stat = 0; stat < CPUACCT_STAT_NSTATS; stat++) {
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seq_printf(sf, "%s %lld\n",
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cpuacct_stat_desc[stat],
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(long long)nsec_to_clock_t(val[stat]));
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}
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return 0;
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}
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static struct cftype files[] = {
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{
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.name = "usage",
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.read_u64 = cpuusage_read,
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.write_u64 = cpuusage_write,
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},
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{
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.name = "usage_user",
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.read_u64 = cpuusage_user_read,
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},
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{
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.name = "usage_sys",
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.read_u64 = cpuusage_sys_read,
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},
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{
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.name = "usage_percpu",
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.seq_show = cpuacct_percpu_seq_show,
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},
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{
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.name = "usage_percpu_user",
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.seq_show = cpuacct_percpu_user_seq_show,
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},
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{
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.name = "usage_percpu_sys",
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.seq_show = cpuacct_percpu_sys_seq_show,
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},
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{
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.name = "usage_all",
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.seq_show = cpuacct_all_seq_show,
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},
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{
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.name = "stat",
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.seq_show = cpuacct_stats_show,
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},
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{ } /* terminate */
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};
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/*
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* charge this task's execution time to its accounting group.
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*
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* called with rq->lock held.
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*/
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void cpuacct_charge(struct task_struct *tsk, u64 cputime)
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{
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struct cpuacct *ca;
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int index = CPUACCT_STAT_SYSTEM;
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struct pt_regs *regs = task_pt_regs(tsk);
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if (regs && user_mode(regs))
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index = CPUACCT_STAT_USER;
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rcu_read_lock();
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for (ca = task_ca(tsk); ca; ca = parent_ca(ca))
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this_cpu_ptr(ca->cpuusage)->usages[index] += cputime;
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rcu_read_unlock();
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}
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/*
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* Add user/system time to cpuacct.
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*
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* Note: it's the caller that updates the account of the root cgroup.
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*/
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void cpuacct_account_field(struct task_struct *tsk, int index, u64 val)
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{
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struct cpuacct *ca;
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rcu_read_lock();
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for (ca = task_ca(tsk); ca != &root_cpuacct; ca = parent_ca(ca))
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this_cpu_ptr(ca->cpustat)->cpustat[index] += val;
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rcu_read_unlock();
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}
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struct cgroup_subsys cpuacct_cgrp_subsys = {
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.css_alloc = cpuacct_css_alloc,
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.css_free = cpuacct_css_free,
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.legacy_cftypes = files,
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.early_init = true,
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};
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