![Frederic Weisbecker](/assets/img/avatar_default.png)
Commit:
f9bcf1e0e0
("sched/cputime: Fix steal time accounting")
... fixes a leak on steal time accounting but forgets to account
the ticks passed in parameters, assuming there is only one to
take into account.
Let's consider that parameter back.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Wanpeng Li <kernellwp@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: linux-tip-commits@vger.kernel.org
Link: http://lkml.kernel.org/r/20160811125822.GB4214@lerouge
Signed-off-by: Ingo Molnar <mingo@kernel.org>
908 lines
23 KiB
C
908 lines
23 KiB
C
#include <linux/export.h>
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#include <linux/sched.h>
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#include <linux/tsacct_kern.h>
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#include <linux/kernel_stat.h>
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#include <linux/static_key.h>
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#include <linux/context_tracking.h>
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#include "sched.h"
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#ifdef CONFIG_PARAVIRT
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#include <asm/paravirt.h>
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#endif
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#ifdef CONFIG_IRQ_TIME_ACCOUNTING
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/*
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* There are no locks covering percpu hardirq/softirq time.
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* They are only modified in vtime_account, on corresponding CPU
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* with interrupts disabled. So, writes are safe.
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* They are read and saved off onto struct rq in update_rq_clock().
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* This may result in other CPU reading this CPU's irq time and can
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* race with irq/vtime_account on this CPU. We would either get old
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* or new value with a side effect of accounting a slice of irq time to wrong
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* task when irq is in progress while we read rq->clock. That is a worthy
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* compromise in place of having locks on each irq in account_system_time.
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*/
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DEFINE_PER_CPU(u64, cpu_hardirq_time);
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DEFINE_PER_CPU(u64, cpu_softirq_time);
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static DEFINE_PER_CPU(u64, irq_start_time);
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static int sched_clock_irqtime;
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void enable_sched_clock_irqtime(void)
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{
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sched_clock_irqtime = 1;
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}
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void disable_sched_clock_irqtime(void)
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{
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sched_clock_irqtime = 0;
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}
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#ifndef CONFIG_64BIT
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DEFINE_PER_CPU(seqcount_t, irq_time_seq);
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#endif /* CONFIG_64BIT */
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/*
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* Called before incrementing preempt_count on {soft,}irq_enter
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* and before decrementing preempt_count on {soft,}irq_exit.
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*/
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void irqtime_account_irq(struct task_struct *curr)
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{
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s64 delta;
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int cpu;
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if (!sched_clock_irqtime)
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return;
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cpu = smp_processor_id();
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delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time);
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__this_cpu_add(irq_start_time, delta);
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irq_time_write_begin();
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/*
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* We do not account for softirq time from ksoftirqd here.
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* We want to continue accounting softirq time to ksoftirqd thread
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* in that case, so as not to confuse scheduler with a special task
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* that do not consume any time, but still wants to run.
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*/
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if (hardirq_count())
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__this_cpu_add(cpu_hardirq_time, delta);
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else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
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__this_cpu_add(cpu_softirq_time, delta);
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irq_time_write_end();
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}
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EXPORT_SYMBOL_GPL(irqtime_account_irq);
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static cputime_t irqtime_account_hi_update(cputime_t maxtime)
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{
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u64 *cpustat = kcpustat_this_cpu->cpustat;
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unsigned long flags;
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cputime_t irq_cputime;
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local_irq_save(flags);
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irq_cputime = nsecs_to_cputime64(this_cpu_read(cpu_hardirq_time)) -
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cpustat[CPUTIME_IRQ];
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irq_cputime = min(irq_cputime, maxtime);
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cpustat[CPUTIME_IRQ] += irq_cputime;
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local_irq_restore(flags);
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return irq_cputime;
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}
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static cputime_t irqtime_account_si_update(cputime_t maxtime)
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{
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u64 *cpustat = kcpustat_this_cpu->cpustat;
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unsigned long flags;
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cputime_t softirq_cputime;
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local_irq_save(flags);
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softirq_cputime = nsecs_to_cputime64(this_cpu_read(cpu_softirq_time)) -
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cpustat[CPUTIME_SOFTIRQ];
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softirq_cputime = min(softirq_cputime, maxtime);
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cpustat[CPUTIME_SOFTIRQ] += softirq_cputime;
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local_irq_restore(flags);
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return softirq_cputime;
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}
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#else /* CONFIG_IRQ_TIME_ACCOUNTING */
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#define sched_clock_irqtime (0)
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static cputime_t irqtime_account_hi_update(cputime_t dummy)
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{
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return 0;
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}
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static cputime_t irqtime_account_si_update(cputime_t dummy)
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{
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return 0;
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}
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#endif /* !CONFIG_IRQ_TIME_ACCOUNTING */
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static inline void task_group_account_field(struct task_struct *p, int index,
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u64 tmp)
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{
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/*
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* Since all updates are sure to touch the root cgroup, we
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* get ourselves ahead and touch it first. If the root cgroup
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* is the only cgroup, then nothing else should be necessary.
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*
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*/
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__this_cpu_add(kernel_cpustat.cpustat[index], tmp);
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cpuacct_account_field(p, index, tmp);
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}
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/*
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* Account user cpu time to a process.
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* @p: the process that the cpu time gets accounted to
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* @cputime: the cpu time spent in user space since the last update
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* @cputime_scaled: cputime scaled by cpu frequency
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*/
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void account_user_time(struct task_struct *p, cputime_t cputime,
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cputime_t cputime_scaled)
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{
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int index;
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/* Add user time to process. */
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p->utime += cputime;
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p->utimescaled += cputime_scaled;
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account_group_user_time(p, cputime);
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index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
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/* Add user time to cpustat. */
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task_group_account_field(p, index, (__force u64) cputime);
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/* Account for user time used */
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acct_account_cputime(p);
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}
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/*
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* Account guest cpu time to a process.
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* @p: the process that the cpu time gets accounted to
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* @cputime: the cpu time spent in virtual machine since the last update
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* @cputime_scaled: cputime scaled by cpu frequency
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*/
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static void account_guest_time(struct task_struct *p, cputime_t cputime,
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cputime_t cputime_scaled)
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{
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u64 *cpustat = kcpustat_this_cpu->cpustat;
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/* Add guest time to process. */
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p->utime += cputime;
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p->utimescaled += cputime_scaled;
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account_group_user_time(p, cputime);
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p->gtime += cputime;
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/* Add guest time to cpustat. */
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if (task_nice(p) > 0) {
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cpustat[CPUTIME_NICE] += (__force u64) cputime;
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cpustat[CPUTIME_GUEST_NICE] += (__force u64) cputime;
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} else {
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cpustat[CPUTIME_USER] += (__force u64) cputime;
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cpustat[CPUTIME_GUEST] += (__force u64) cputime;
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}
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}
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/*
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* Account system cpu time to a process and desired cpustat field
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* @p: the process that the cpu time gets accounted to
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* @cputime: the cpu time spent in kernel space since the last update
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* @cputime_scaled: cputime scaled by cpu frequency
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* @target_cputime64: pointer to cpustat field that has to be updated
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*/
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static inline
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void __account_system_time(struct task_struct *p, cputime_t cputime,
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cputime_t cputime_scaled, int index)
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{
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/* Add system time to process. */
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p->stime += cputime;
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p->stimescaled += cputime_scaled;
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account_group_system_time(p, cputime);
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/* Add system time to cpustat. */
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task_group_account_field(p, index, (__force u64) cputime);
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/* Account for system time used */
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acct_account_cputime(p);
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}
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/*
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* Account system cpu time to a process.
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* @p: the process that the cpu time gets accounted to
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* @hardirq_offset: the offset to subtract from hardirq_count()
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* @cputime: the cpu time spent in kernel space since the last update
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* @cputime_scaled: cputime scaled by cpu frequency
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*/
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void account_system_time(struct task_struct *p, int hardirq_offset,
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cputime_t cputime, cputime_t cputime_scaled)
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{
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int index;
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if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
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account_guest_time(p, cputime, cputime_scaled);
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return;
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}
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if (hardirq_count() - hardirq_offset)
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index = CPUTIME_IRQ;
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else if (in_serving_softirq())
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index = CPUTIME_SOFTIRQ;
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else
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index = CPUTIME_SYSTEM;
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__account_system_time(p, cputime, cputime_scaled, index);
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}
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/*
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* Account for involuntary wait time.
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* @cputime: the cpu time spent in involuntary wait
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*/
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void account_steal_time(cputime_t cputime)
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{
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u64 *cpustat = kcpustat_this_cpu->cpustat;
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cpustat[CPUTIME_STEAL] += (__force u64) cputime;
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}
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/*
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* Account for idle time.
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* @cputime: the cpu time spent in idle wait
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*/
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void account_idle_time(cputime_t cputime)
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{
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u64 *cpustat = kcpustat_this_cpu->cpustat;
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struct rq *rq = this_rq();
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if (atomic_read(&rq->nr_iowait) > 0)
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cpustat[CPUTIME_IOWAIT] += (__force u64) cputime;
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else
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cpustat[CPUTIME_IDLE] += (__force u64) cputime;
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}
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static __always_inline cputime_t steal_account_process_time(cputime_t maxtime)
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{
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#ifdef CONFIG_PARAVIRT
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if (static_key_false(¶virt_steal_enabled)) {
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cputime_t steal_cputime;
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u64 steal;
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steal = paravirt_steal_clock(smp_processor_id());
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steal -= this_rq()->prev_steal_time;
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steal_cputime = min(nsecs_to_cputime(steal), maxtime);
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account_steal_time(steal_cputime);
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this_rq()->prev_steal_time += cputime_to_nsecs(steal_cputime);
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return steal_cputime;
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}
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#endif
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return 0;
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}
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/*
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* Account how much elapsed time was spent in steal, irq, or softirq time.
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*/
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static inline cputime_t account_other_time(cputime_t max)
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{
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cputime_t accounted;
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accounted = steal_account_process_time(max);
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if (accounted < max)
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accounted += irqtime_account_hi_update(max - accounted);
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if (accounted < max)
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accounted += irqtime_account_si_update(max - accounted);
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return accounted;
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}
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/*
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* Accumulate raw cputime values of dead tasks (sig->[us]time) and live
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* tasks (sum on group iteration) belonging to @tsk's group.
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*/
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void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
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{
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struct signal_struct *sig = tsk->signal;
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cputime_t utime, stime;
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struct task_struct *t;
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unsigned int seq, nextseq;
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unsigned long flags;
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rcu_read_lock();
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/* Attempt a lockless read on the first round. */
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nextseq = 0;
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do {
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seq = nextseq;
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flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq);
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times->utime = sig->utime;
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times->stime = sig->stime;
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times->sum_exec_runtime = sig->sum_sched_runtime;
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for_each_thread(tsk, t) {
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task_cputime(t, &utime, &stime);
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times->utime += utime;
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times->stime += stime;
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times->sum_exec_runtime += task_sched_runtime(t);
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}
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/* If lockless access failed, take the lock. */
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nextseq = 1;
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} while (need_seqretry(&sig->stats_lock, seq));
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done_seqretry_irqrestore(&sig->stats_lock, seq, flags);
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rcu_read_unlock();
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}
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#ifdef CONFIG_IRQ_TIME_ACCOUNTING
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/*
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* Account a tick to a process and cpustat
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* @p: the process that the cpu time gets accounted to
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* @user_tick: is the tick from userspace
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* @rq: the pointer to rq
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*
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* Tick demultiplexing follows the order
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* - pending hardirq update
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* - pending softirq update
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* - user_time
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* - idle_time
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* - system time
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* - check for guest_time
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* - else account as system_time
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*
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* Check for hardirq is done both for system and user time as there is
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* no timer going off while we are on hardirq and hence we may never get an
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* opportunity to update it solely in system time.
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* p->stime and friends are only updated on system time and not on irq
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* softirq as those do not count in task exec_runtime any more.
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*/
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static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
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struct rq *rq, int ticks)
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{
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u64 cputime = (__force u64) cputime_one_jiffy * ticks;
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cputime_t scaled, other;
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/*
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* When returning from idle, many ticks can get accounted at
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* once, including some ticks of steal, irq, and softirq time.
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* Subtract those ticks from the amount of time accounted to
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* idle, or potentially user or system time. Due to rounding,
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* other time can exceed ticks occasionally.
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*/
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other = account_other_time(cputime);
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if (other >= cputime)
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return;
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cputime -= other;
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scaled = cputime_to_scaled(cputime);
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if (this_cpu_ksoftirqd() == p) {
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/*
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* ksoftirqd time do not get accounted in cpu_softirq_time.
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* So, we have to handle it separately here.
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* Also, p->stime needs to be updated for ksoftirqd.
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*/
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__account_system_time(p, cputime, scaled, CPUTIME_SOFTIRQ);
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} else if (user_tick) {
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account_user_time(p, cputime, scaled);
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} else if (p == rq->idle) {
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account_idle_time(cputime);
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} else if (p->flags & PF_VCPU) { /* System time or guest time */
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account_guest_time(p, cputime, scaled);
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} else {
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__account_system_time(p, cputime, scaled, CPUTIME_SYSTEM);
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}
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}
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static void irqtime_account_idle_ticks(int ticks)
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{
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struct rq *rq = this_rq();
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irqtime_account_process_tick(current, 0, rq, ticks);
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}
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#else /* CONFIG_IRQ_TIME_ACCOUNTING */
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static inline void irqtime_account_idle_ticks(int ticks) {}
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static inline void irqtime_account_process_tick(struct task_struct *p, int user_tick,
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struct rq *rq, int nr_ticks) {}
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#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
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/*
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* Use precise platform statistics if available:
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*/
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING
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#ifndef __ARCH_HAS_VTIME_TASK_SWITCH
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void vtime_common_task_switch(struct task_struct *prev)
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{
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if (is_idle_task(prev))
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vtime_account_idle(prev);
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else
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vtime_account_system(prev);
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
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vtime_account_user(prev);
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#endif
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arch_vtime_task_switch(prev);
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}
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#endif
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#endif /* CONFIG_VIRT_CPU_ACCOUNTING */
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
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/*
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* Archs that account the whole time spent in the idle task
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* (outside irq) as idle time can rely on this and just implement
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* vtime_account_system() and vtime_account_idle(). Archs that
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* have other meaning of the idle time (s390 only includes the
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* time spent by the CPU when it's in low power mode) must override
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* vtime_account().
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*/
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#ifndef __ARCH_HAS_VTIME_ACCOUNT
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void vtime_account_irq_enter(struct task_struct *tsk)
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{
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if (!in_interrupt() && is_idle_task(tsk))
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vtime_account_idle(tsk);
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else
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vtime_account_system(tsk);
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}
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EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
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#endif /* __ARCH_HAS_VTIME_ACCOUNT */
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void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
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{
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*ut = p->utime;
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*st = p->stime;
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}
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EXPORT_SYMBOL_GPL(task_cputime_adjusted);
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void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
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{
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struct task_cputime cputime;
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thread_group_cputime(p, &cputime);
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*ut = cputime.utime;
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*st = cputime.stime;
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}
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#else /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
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/*
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* Account a single tick of cpu time.
|
|
* @p: the process that the cpu time gets accounted to
|
|
* @user_tick: indicates if the tick is a user or a system tick
|
|
*/
|
|
void account_process_tick(struct task_struct *p, int user_tick)
|
|
{
|
|
cputime_t cputime, scaled, steal;
|
|
struct rq *rq = this_rq();
|
|
|
|
if (vtime_accounting_cpu_enabled())
|
|
return;
|
|
|
|
if (sched_clock_irqtime) {
|
|
irqtime_account_process_tick(p, user_tick, rq, 1);
|
|
return;
|
|
}
|
|
|
|
cputime = cputime_one_jiffy;
|
|
steal = steal_account_process_time(cputime);
|
|
|
|
if (steal >= cputime)
|
|
return;
|
|
|
|
cputime -= steal;
|
|
scaled = cputime_to_scaled(cputime);
|
|
|
|
if (user_tick)
|
|
account_user_time(p, cputime, scaled);
|
|
else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
|
|
account_system_time(p, HARDIRQ_OFFSET, cputime, scaled);
|
|
else
|
|
account_idle_time(cputime);
|
|
}
|
|
|
|
/*
|
|
* Account multiple ticks of idle time.
|
|
* @ticks: number of stolen ticks
|
|
*/
|
|
void account_idle_ticks(unsigned long ticks)
|
|
{
|
|
cputime_t cputime, steal;
|
|
|
|
if (sched_clock_irqtime) {
|
|
irqtime_account_idle_ticks(ticks);
|
|
return;
|
|
}
|
|
|
|
cputime = jiffies_to_cputime(ticks);
|
|
steal = steal_account_process_time(cputime);
|
|
|
|
if (steal >= cputime)
|
|
return;
|
|
|
|
cputime -= steal;
|
|
account_idle_time(cputime);
|
|
}
|
|
|
|
/*
|
|
* Perform (stime * rtime) / total, but avoid multiplication overflow by
|
|
* loosing precision when the numbers are big.
|
|
*/
|
|
static cputime_t scale_stime(u64 stime, u64 rtime, u64 total)
|
|
{
|
|
u64 scaled;
|
|
|
|
for (;;) {
|
|
/* Make sure "rtime" is the bigger of stime/rtime */
|
|
if (stime > rtime)
|
|
swap(rtime, stime);
|
|
|
|
/* Make sure 'total' fits in 32 bits */
|
|
if (total >> 32)
|
|
goto drop_precision;
|
|
|
|
/* Does rtime (and thus stime) fit in 32 bits? */
|
|
if (!(rtime >> 32))
|
|
break;
|
|
|
|
/* Can we just balance rtime/stime rather than dropping bits? */
|
|
if (stime >> 31)
|
|
goto drop_precision;
|
|
|
|
/* We can grow stime and shrink rtime and try to make them both fit */
|
|
stime <<= 1;
|
|
rtime >>= 1;
|
|
continue;
|
|
|
|
drop_precision:
|
|
/* We drop from rtime, it has more bits than stime */
|
|
rtime >>= 1;
|
|
total >>= 1;
|
|
}
|
|
|
|
/*
|
|
* Make sure gcc understands that this is a 32x32->64 multiply,
|
|
* followed by a 64/32->64 divide.
|
|
*/
|
|
scaled = div_u64((u64) (u32) stime * (u64) (u32) rtime, (u32)total);
|
|
return (__force cputime_t) scaled;
|
|
}
|
|
|
|
/*
|
|
* Adjust tick based cputime random precision against scheduler runtime
|
|
* accounting.
|
|
*
|
|
* Tick based cputime accounting depend on random scheduling timeslices of a
|
|
* task to be interrupted or not by the timer. Depending on these
|
|
* circumstances, the number of these interrupts may be over or
|
|
* under-optimistic, matching the real user and system cputime with a variable
|
|
* precision.
|
|
*
|
|
* Fix this by scaling these tick based values against the total runtime
|
|
* accounted by the CFS scheduler.
|
|
*
|
|
* This code provides the following guarantees:
|
|
*
|
|
* stime + utime == rtime
|
|
* stime_i+1 >= stime_i, utime_i+1 >= utime_i
|
|
*
|
|
* Assuming that rtime_i+1 >= rtime_i.
|
|
*/
|
|
static void cputime_adjust(struct task_cputime *curr,
|
|
struct prev_cputime *prev,
|
|
cputime_t *ut, cputime_t *st)
|
|
{
|
|
cputime_t rtime, stime, utime;
|
|
unsigned long flags;
|
|
|
|
/* Serialize concurrent callers such that we can honour our guarantees */
|
|
raw_spin_lock_irqsave(&prev->lock, flags);
|
|
rtime = nsecs_to_cputime(curr->sum_exec_runtime);
|
|
|
|
/*
|
|
* This is possible under two circumstances:
|
|
* - rtime isn't monotonic after all (a bug);
|
|
* - we got reordered by the lock.
|
|
*
|
|
* In both cases this acts as a filter such that the rest of the code
|
|
* can assume it is monotonic regardless of anything else.
|
|
*/
|
|
if (prev->stime + prev->utime >= rtime)
|
|
goto out;
|
|
|
|
stime = curr->stime;
|
|
utime = curr->utime;
|
|
|
|
if (utime == 0) {
|
|
stime = rtime;
|
|
goto update;
|
|
}
|
|
|
|
if (stime == 0) {
|
|
utime = rtime;
|
|
goto update;
|
|
}
|
|
|
|
stime = scale_stime((__force u64)stime, (__force u64)rtime,
|
|
(__force u64)(stime + utime));
|
|
|
|
/*
|
|
* Make sure stime doesn't go backwards; this preserves monotonicity
|
|
* for utime because rtime is monotonic.
|
|
*
|
|
* utime_i+1 = rtime_i+1 - stime_i
|
|
* = rtime_i+1 - (rtime_i - utime_i)
|
|
* = (rtime_i+1 - rtime_i) + utime_i
|
|
* >= utime_i
|
|
*/
|
|
if (stime < prev->stime)
|
|
stime = prev->stime;
|
|
utime = rtime - stime;
|
|
|
|
/*
|
|
* Make sure utime doesn't go backwards; this still preserves
|
|
* monotonicity for stime, analogous argument to above.
|
|
*/
|
|
if (utime < prev->utime) {
|
|
utime = prev->utime;
|
|
stime = rtime - utime;
|
|
}
|
|
|
|
update:
|
|
prev->stime = stime;
|
|
prev->utime = utime;
|
|
out:
|
|
*ut = prev->utime;
|
|
*st = prev->stime;
|
|
raw_spin_unlock_irqrestore(&prev->lock, flags);
|
|
}
|
|
|
|
void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
|
|
{
|
|
struct task_cputime cputime = {
|
|
.sum_exec_runtime = p->se.sum_exec_runtime,
|
|
};
|
|
|
|
task_cputime(p, &cputime.utime, &cputime.stime);
|
|
cputime_adjust(&cputime, &p->prev_cputime, ut, st);
|
|
}
|
|
EXPORT_SYMBOL_GPL(task_cputime_adjusted);
|
|
|
|
void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
|
|
{
|
|
struct task_cputime cputime;
|
|
|
|
thread_group_cputime(p, &cputime);
|
|
cputime_adjust(&cputime, &p->signal->prev_cputime, ut, st);
|
|
}
|
|
#endif /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
|
|
|
|
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
|
|
static cputime_t vtime_delta(struct task_struct *tsk)
|
|
{
|
|
unsigned long now = READ_ONCE(jiffies);
|
|
|
|
if (time_before(now, (unsigned long)tsk->vtime_snap))
|
|
return 0;
|
|
|
|
return jiffies_to_cputime(now - tsk->vtime_snap);
|
|
}
|
|
|
|
static cputime_t get_vtime_delta(struct task_struct *tsk)
|
|
{
|
|
unsigned long now = READ_ONCE(jiffies);
|
|
cputime_t delta, other;
|
|
|
|
delta = jiffies_to_cputime(now - tsk->vtime_snap);
|
|
other = account_other_time(delta);
|
|
WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_INACTIVE);
|
|
tsk->vtime_snap = now;
|
|
|
|
return delta - other;
|
|
}
|
|
|
|
static void __vtime_account_system(struct task_struct *tsk)
|
|
{
|
|
cputime_t delta_cpu = get_vtime_delta(tsk);
|
|
|
|
account_system_time(tsk, irq_count(), delta_cpu, cputime_to_scaled(delta_cpu));
|
|
}
|
|
|
|
void vtime_account_system(struct task_struct *tsk)
|
|
{
|
|
if (!vtime_delta(tsk))
|
|
return;
|
|
|
|
write_seqcount_begin(&tsk->vtime_seqcount);
|
|
__vtime_account_system(tsk);
|
|
write_seqcount_end(&tsk->vtime_seqcount);
|
|
}
|
|
|
|
void vtime_account_user(struct task_struct *tsk)
|
|
{
|
|
cputime_t delta_cpu;
|
|
|
|
write_seqcount_begin(&tsk->vtime_seqcount);
|
|
tsk->vtime_snap_whence = VTIME_SYS;
|
|
if (vtime_delta(tsk)) {
|
|
delta_cpu = get_vtime_delta(tsk);
|
|
account_user_time(tsk, delta_cpu, cputime_to_scaled(delta_cpu));
|
|
}
|
|
write_seqcount_end(&tsk->vtime_seqcount);
|
|
}
|
|
|
|
void vtime_user_enter(struct task_struct *tsk)
|
|
{
|
|
write_seqcount_begin(&tsk->vtime_seqcount);
|
|
if (vtime_delta(tsk))
|
|
__vtime_account_system(tsk);
|
|
tsk->vtime_snap_whence = VTIME_USER;
|
|
write_seqcount_end(&tsk->vtime_seqcount);
|
|
}
|
|
|
|
void vtime_guest_enter(struct task_struct *tsk)
|
|
{
|
|
/*
|
|
* The flags must be updated under the lock with
|
|
* the vtime_snap flush and update.
|
|
* That enforces a right ordering and update sequence
|
|
* synchronization against the reader (task_gtime())
|
|
* that can thus safely catch up with a tickless delta.
|
|
*/
|
|
write_seqcount_begin(&tsk->vtime_seqcount);
|
|
if (vtime_delta(tsk))
|
|
__vtime_account_system(tsk);
|
|
current->flags |= PF_VCPU;
|
|
write_seqcount_end(&tsk->vtime_seqcount);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vtime_guest_enter);
|
|
|
|
void vtime_guest_exit(struct task_struct *tsk)
|
|
{
|
|
write_seqcount_begin(&tsk->vtime_seqcount);
|
|
__vtime_account_system(tsk);
|
|
current->flags &= ~PF_VCPU;
|
|
write_seqcount_end(&tsk->vtime_seqcount);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vtime_guest_exit);
|
|
|
|
void vtime_account_idle(struct task_struct *tsk)
|
|
{
|
|
cputime_t delta_cpu = get_vtime_delta(tsk);
|
|
|
|
account_idle_time(delta_cpu);
|
|
}
|
|
|
|
void arch_vtime_task_switch(struct task_struct *prev)
|
|
{
|
|
write_seqcount_begin(&prev->vtime_seqcount);
|
|
prev->vtime_snap_whence = VTIME_INACTIVE;
|
|
write_seqcount_end(&prev->vtime_seqcount);
|
|
|
|
write_seqcount_begin(¤t->vtime_seqcount);
|
|
current->vtime_snap_whence = VTIME_SYS;
|
|
current->vtime_snap = jiffies;
|
|
write_seqcount_end(¤t->vtime_seqcount);
|
|
}
|
|
|
|
void vtime_init_idle(struct task_struct *t, int cpu)
|
|
{
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
write_seqcount_begin(&t->vtime_seqcount);
|
|
t->vtime_snap_whence = VTIME_SYS;
|
|
t->vtime_snap = jiffies;
|
|
write_seqcount_end(&t->vtime_seqcount);
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
cputime_t task_gtime(struct task_struct *t)
|
|
{
|
|
unsigned int seq;
|
|
cputime_t gtime;
|
|
|
|
if (!vtime_accounting_enabled())
|
|
return t->gtime;
|
|
|
|
do {
|
|
seq = read_seqcount_begin(&t->vtime_seqcount);
|
|
|
|
gtime = t->gtime;
|
|
if (t->vtime_snap_whence == VTIME_SYS && t->flags & PF_VCPU)
|
|
gtime += vtime_delta(t);
|
|
|
|
} while (read_seqcount_retry(&t->vtime_seqcount, seq));
|
|
|
|
return gtime;
|
|
}
|
|
|
|
/*
|
|
* Fetch cputime raw values from fields of task_struct and
|
|
* add up the pending nohz execution time since the last
|
|
* cputime snapshot.
|
|
*/
|
|
static void
|
|
fetch_task_cputime(struct task_struct *t,
|
|
cputime_t *u_dst, cputime_t *s_dst,
|
|
cputime_t *u_src, cputime_t *s_src,
|
|
cputime_t *udelta, cputime_t *sdelta)
|
|
{
|
|
unsigned int seq;
|
|
unsigned long long delta;
|
|
|
|
do {
|
|
*udelta = 0;
|
|
*sdelta = 0;
|
|
|
|
seq = read_seqcount_begin(&t->vtime_seqcount);
|
|
|
|
if (u_dst)
|
|
*u_dst = *u_src;
|
|
if (s_dst)
|
|
*s_dst = *s_src;
|
|
|
|
/* Task is sleeping, nothing to add */
|
|
if (t->vtime_snap_whence == VTIME_INACTIVE ||
|
|
is_idle_task(t))
|
|
continue;
|
|
|
|
delta = vtime_delta(t);
|
|
|
|
/*
|
|
* Task runs either in user or kernel space, add pending nohz time to
|
|
* the right place.
|
|
*/
|
|
if (t->vtime_snap_whence == VTIME_USER || t->flags & PF_VCPU) {
|
|
*udelta = delta;
|
|
} else {
|
|
if (t->vtime_snap_whence == VTIME_SYS)
|
|
*sdelta = delta;
|
|
}
|
|
} while (read_seqcount_retry(&t->vtime_seqcount, seq));
|
|
}
|
|
|
|
|
|
void task_cputime(struct task_struct *t, cputime_t *utime, cputime_t *stime)
|
|
{
|
|
cputime_t udelta, sdelta;
|
|
|
|
if (!vtime_accounting_enabled()) {
|
|
if (utime)
|
|
*utime = t->utime;
|
|
if (stime)
|
|
*stime = t->stime;
|
|
return;
|
|
}
|
|
|
|
fetch_task_cputime(t, utime, stime, &t->utime,
|
|
&t->stime, &udelta, &sdelta);
|
|
if (utime)
|
|
*utime += udelta;
|
|
if (stime)
|
|
*stime += sdelta;
|
|
}
|
|
|
|
void task_cputime_scaled(struct task_struct *t,
|
|
cputime_t *utimescaled, cputime_t *stimescaled)
|
|
{
|
|
cputime_t udelta, sdelta;
|
|
|
|
if (!vtime_accounting_enabled()) {
|
|
if (utimescaled)
|
|
*utimescaled = t->utimescaled;
|
|
if (stimescaled)
|
|
*stimescaled = t->stimescaled;
|
|
return;
|
|
}
|
|
|
|
fetch_task_cputime(t, utimescaled, stimescaled,
|
|
&t->utimescaled, &t->stimescaled, &udelta, &sdelta);
|
|
if (utimescaled)
|
|
*utimescaled += cputime_to_scaled(udelta);
|
|
if (stimescaled)
|
|
*stimescaled += cputime_to_scaled(sdelta);
|
|
}
|
|
#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
|