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![Tejun Heo](/assets/img/avatar_default.png)
In preparation of conversion to kernfs, cgroup file handling is updated so that it can be easily mapped to kernfs. This patch replaces cftype->read_seq_string() with cftype->seq_show() which is not limited to single_open() operation and will map directcly to kernfs seq_file interface. The conversions are mechanical. As ->seq_show() doesn't have @css and @cft, the functions which make use of them are converted to use seq_css() and seq_cft() respectively. In several occassions, e.f. if it has seq_string in its name, the function name is updated to fit the new method better. This patch does not introduce any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Aristeu Rozanski <arozansk@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Neil Horman <nhorman@tuxdriver.com>
285 lines
5.9 KiB
C
285 lines
5.9 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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/* 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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u64 __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_subsys_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(css_parent(&ca->css));
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}
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static DEFINE_PER_CPU(u64, 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(u64);
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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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{
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u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
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u64 data;
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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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data = *cpuusage;
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raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
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#else
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data = *cpuusage;
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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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u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
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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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*cpuusage = val;
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raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
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#else
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*cpuusage = val;
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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, struct cftype *cft)
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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_present_cpu(i)
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totalcpuusage += cpuacct_cpuusage_read(ca, i);
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return totalcpuusage;
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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 reset)
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{
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struct cpuacct *ca = css_ca(css);
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int err = 0;
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int i;
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if (reset) {
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err = -EINVAL;
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goto out;
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}
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for_each_present_cpu(i)
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cpuacct_cpuusage_write(ca, i, 0);
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out:
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return err;
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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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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_present_cpu(i) {
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percpu = cpuacct_cpuusage_read(ca, i);
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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 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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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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int cpu;
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s64 val = 0;
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for_each_online_cpu(cpu) {
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struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
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val += kcpustat->cpustat[CPUTIME_USER];
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val += kcpustat->cpustat[CPUTIME_NICE];
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}
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val = cputime64_to_clock_t(val);
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seq_printf(sf, "%s %lld\n", cpuacct_stat_desc[CPUACCT_STAT_USER], val);
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val = 0;
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for_each_online_cpu(cpu) {
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struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
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val += kcpustat->cpustat[CPUTIME_SYSTEM];
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val += kcpustat->cpustat[CPUTIME_IRQ];
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val += kcpustat->cpustat[CPUTIME_SOFTIRQ];
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}
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val = cputime64_to_clock_t(val);
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seq_printf(sf, "%s %lld\n", cpuacct_stat_desc[CPUACCT_STAT_SYSTEM], val);
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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_percpu",
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.seq_show = cpuacct_percpu_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 cpu;
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cpu = task_cpu(tsk);
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rcu_read_lock();
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ca = task_ca(tsk);
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while (true) {
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u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
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*cpuusage += cputime;
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ca = parent_ca(ca);
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if (!ca)
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break;
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}
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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 *p, int index, u64 val)
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{
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struct kernel_cpustat *kcpustat;
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struct cpuacct *ca;
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rcu_read_lock();
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ca = task_ca(p);
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while (ca != &root_cpuacct) {
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kcpustat = this_cpu_ptr(ca->cpustat);
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kcpustat->cpustat[index] += val;
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ca = parent_ca(ca);
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}
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rcu_read_unlock();
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}
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struct cgroup_subsys cpuacct_subsys = {
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.name = "cpuacct",
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.css_alloc = cpuacct_css_alloc,
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.css_free = cpuacct_css_free,
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.subsys_id = cpuacct_subsys_id,
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.base_cftypes = files,
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.early_init = 1,
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};
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