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1078 lines
26 KiB
1078 lines
26 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Simple CPU accounting cgroup controller |
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*/ |
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#include "sched.h" |
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|
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#ifdef CONFIG_IRQ_TIME_ACCOUNTING |
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|
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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(struct irqtime, cpu_irqtime); |
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static int sched_clock_irqtime; |
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|
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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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|
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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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static void irqtime_account_delta(struct irqtime *irqtime, u64 delta, |
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enum cpu_usage_stat idx) |
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{ |
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u64 *cpustat = kcpustat_this_cpu->cpustat; |
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u64_stats_update_begin(&irqtime->sync); |
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cpustat[idx] += delta; |
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irqtime->total += delta; |
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irqtime->tick_delta += delta; |
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u64_stats_update_end(&irqtime->sync); |
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} |
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|
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/* |
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* Called after 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, unsigned int offset) |
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{ |
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struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime); |
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unsigned int pc; |
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s64 delta; |
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int cpu; |
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|
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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) - irqtime->irq_start_time; |
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irqtime->irq_start_time += delta; |
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pc = irq_count() - offset; |
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|
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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 (pc & HARDIRQ_MASK) |
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irqtime_account_delta(irqtime, delta, CPUTIME_IRQ); |
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else if ((pc & SOFTIRQ_OFFSET) && curr != this_cpu_ksoftirqd()) |
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irqtime_account_delta(irqtime, delta, CPUTIME_SOFTIRQ); |
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} |
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|
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static u64 irqtime_tick_accounted(u64 maxtime) |
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{ |
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struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime); |
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u64 delta; |
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|
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delta = min(irqtime->tick_delta, maxtime); |
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irqtime->tick_delta -= delta; |
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return delta; |
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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 u64 irqtime_tick_accounted(u64 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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cgroup_account_cputime_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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*/ |
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void account_user_time(struct task_struct *p, u64 cputime) |
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{ |
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int index; |
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|
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/* Add user time to process. */ |
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p->utime += cputime; |
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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, cputime); |
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|
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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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/* |
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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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*/ |
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void account_guest_time(struct task_struct *p, u64 cputime) |
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{ |
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u64 *cpustat = kcpustat_this_cpu->cpustat; |
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|
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/* Add guest time to process. */ |
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p->utime += cputime; |
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account_group_user_time(p, cputime); |
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p->gtime += cputime; |
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|
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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] += cputime; |
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cpustat[CPUTIME_GUEST_NICE] += cputime; |
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} else { |
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cpustat[CPUTIME_USER] += cputime; |
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cpustat[CPUTIME_GUEST] += cputime; |
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} |
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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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* @index: pointer to cpustat field that has to be updated |
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*/ |
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void account_system_index_time(struct task_struct *p, |
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u64 cputime, enum cpu_usage_stat 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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account_group_system_time(p, cputime); |
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|
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/* Add system time to cpustat. */ |
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task_group_account_field(p, index, cputime); |
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|
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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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/* |
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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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*/ |
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void account_system_time(struct task_struct *p, int hardirq_offset, u64 cputime) |
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{ |
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int index; |
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|
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if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) { |
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account_guest_time(p, cputime); |
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return; |
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} |
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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_index_time(p, cputime, index); |
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} |
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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(u64 cputime) |
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{ |
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u64 *cpustat = kcpustat_this_cpu->cpustat; |
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|
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cpustat[CPUTIME_STEAL] += cputime; |
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} |
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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(u64 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] += cputime; |
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else |
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cpustat[CPUTIME_IDLE] += cputime; |
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} |
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|
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/* |
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* When a guest is interrupted for a longer amount of time, missed clock |
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* ticks are not redelivered later. Due to that, this function may on |
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* occasion account more time than the calling functions think elapsed. |
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*/ |
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static __always_inline u64 steal_account_process_time(u64 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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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 = min(steal, maxtime); |
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account_steal_time(steal); |
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this_rq()->prev_steal_time += steal; |
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return steal; |
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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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/* |
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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 u64 account_other_time(u64 max) |
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{ |
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u64 accounted; |
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|
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lockdep_assert_irqs_disabled(); |
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accounted = steal_account_process_time(max); |
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if (accounted < max) |
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accounted += irqtime_tick_accounted(max - accounted); |
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return accounted; |
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} |
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#ifdef CONFIG_64BIT |
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static inline u64 read_sum_exec_runtime(struct task_struct *t) |
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{ |
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return t->se.sum_exec_runtime; |
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} |
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#else |
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static u64 read_sum_exec_runtime(struct task_struct *t) |
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{ |
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u64 ns; |
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struct rq_flags rf; |
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struct rq *rq; |
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rq = task_rq_lock(t, &rf); |
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ns = t->se.sum_exec_runtime; |
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task_rq_unlock(rq, t, &rf); |
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return ns; |
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} |
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#endif |
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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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u64 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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/* |
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* Update current task runtime to account pending time since last |
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* scheduler action or thread_group_cputime() call. This thread group |
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* might have other running tasks on different CPUs, but updating |
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* their runtime can affect syscall performance, so we skip account |
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* those pending times and rely only on values updated on tick or |
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* other scheduler action. |
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*/ |
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if (same_thread_group(current, tsk)) |
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(void) task_sched_runtime(current); |
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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 += read_sum_exec_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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int ticks) |
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{ |
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u64 other, cputime = TICK_NSEC * ticks; |
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|
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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(ULONG_MAX); |
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if (other >= cputime) |
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return; |
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|
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cputime -= other; |
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|
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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_index_time(p, cputime, CPUTIME_SOFTIRQ); |
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} else if (user_tick) { |
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account_user_time(p, cputime); |
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} else if (p == this_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); |
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} else { |
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account_system_index_time(p, cputime, CPUTIME_SYSTEM); |
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} |
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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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irqtime_account_process_tick(current, 0, 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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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_NATIVE |
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|
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# ifndef __ARCH_HAS_VTIME_TASK_SWITCH |
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void vtime_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_kernel(prev); |
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|
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vtime_flush(prev); |
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arch_vtime_task_switch(prev); |
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} |
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# endif |
|
|
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void vtime_account_irq(struct task_struct *tsk, unsigned int offset) |
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{ |
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unsigned int pc = irq_count() - offset; |
|
|
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if (pc & HARDIRQ_OFFSET) { |
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vtime_account_hardirq(tsk); |
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} else if (pc & SOFTIRQ_OFFSET) { |
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vtime_account_softirq(tsk); |
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} else if (!IS_ENABLED(CONFIG_HAVE_VIRT_CPU_ACCOUNTING_IDLE) && |
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is_idle_task(tsk)) { |
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vtime_account_idle(tsk); |
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} else { |
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vtime_account_kernel(tsk); |
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} |
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} |
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|
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void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev, |
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u64 *ut, u64 *st) |
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{ |
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*ut = curr->utime; |
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*st = curr->stime; |
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} |
|
|
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void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *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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|
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void thread_group_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *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. |
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* @p: the process that the CPU time gets accounted to |
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* @user_tick: indicates if the tick is a user or a system tick |
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*/ |
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void account_process_tick(struct task_struct *p, int user_tick) |
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{ |
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u64 cputime, steal; |
|
|
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if (vtime_accounting_enabled_this_cpu()) |
|
return; |
|
|
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if (sched_clock_irqtime) { |
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irqtime_account_process_tick(p, user_tick, 1); |
|
return; |
|
} |
|
|
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cputime = TICK_NSEC; |
|
steal = steal_account_process_time(ULONG_MAX); |
|
|
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if (steal >= cputime) |
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return; |
|
|
|
cputime -= steal; |
|
|
|
if (user_tick) |
|
account_user_time(p, cputime); |
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else if ((p != this_rq()->idle) || (irq_count() != HARDIRQ_OFFSET)) |
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account_system_time(p, HARDIRQ_OFFSET, cputime); |
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else |
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account_idle_time(cputime); |
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} |
|
|
|
/* |
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* Account multiple ticks of idle time. |
|
* @ticks: number of stolen ticks |
|
*/ |
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void account_idle_ticks(unsigned long ticks) |
|
{ |
|
u64 cputime, steal; |
|
|
|
if (sched_clock_irqtime) { |
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irqtime_account_idle_ticks(ticks); |
|
return; |
|
} |
|
|
|
cputime = ticks * TICK_NSEC; |
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steal = steal_account_process_time(ULONG_MAX); |
|
|
|
if (steal >= cputime) |
|
return; |
|
|
|
cputime -= steal; |
|
account_idle_time(cputime); |
|
} |
|
|
|
/* |
|
* Adjust tick based cputime random precision against scheduler runtime |
|
* accounting. |
|
* |
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* Tick based cputime accounting depend on random scheduling timeslices of a |
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* task to be interrupted or not by the timer. Depending on these |
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* circumstances, the number of these interrupts may be over or |
|
* under-optimistic, matching the real user and system cputime with a variable |
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* precision. |
|
* |
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* Fix this by scaling these tick based values against the total runtime |
|
* accounted by the CFS scheduler. |
|
* |
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* This code provides the following guarantees: |
|
* |
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* stime + utime == rtime |
|
* stime_i+1 >= stime_i, utime_i+1 >= utime_i |
|
* |
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* Assuming that rtime_i+1 >= rtime_i. |
|
*/ |
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void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev, |
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u64 *ut, u64 *st) |
|
{ |
|
u64 rtime, stime, utime; |
|
unsigned long flags; |
|
|
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/* Serialize concurrent callers such that we can honour our guarantees */ |
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raw_spin_lock_irqsave(&prev->lock, flags); |
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rtime = 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. |
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*/ |
|
if (prev->stime + prev->utime >= rtime) |
|
goto out; |
|
|
|
stime = curr->stime; |
|
utime = curr->utime; |
|
|
|
/* |
|
* If either stime or utime are 0, assume all runtime is userspace. |
|
* Once a task gets some ticks, the monotonicity code at 'update:' |
|
* will ensure things converge to the observed ratio. |
|
*/ |
|
if (stime == 0) { |
|
utime = rtime; |
|
goto update; |
|
} |
|
|
|
if (utime == 0) { |
|
stime = rtime; |
|
goto update; |
|
} |
|
|
|
stime = mul_u64_u64_div_u64(stime, rtime, stime + utime); |
|
|
|
update: |
|
/* |
|
* 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; |
|
} |
|
|
|
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, u64 *ut, u64 *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, u64 *ut, u64 *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 u64 vtime_delta(struct vtime *vtime) |
|
{ |
|
unsigned long long clock; |
|
|
|
clock = sched_clock(); |
|
if (clock < vtime->starttime) |
|
return 0; |
|
|
|
return clock - vtime->starttime; |
|
} |
|
|
|
static u64 get_vtime_delta(struct vtime *vtime) |
|
{ |
|
u64 delta = vtime_delta(vtime); |
|
u64 other; |
|
|
|
/* |
|
* Unlike tick based timing, vtime based timing never has lost |
|
* ticks, and no need for steal time accounting to make up for |
|
* lost ticks. Vtime accounts a rounded version of actual |
|
* elapsed time. Limit account_other_time to prevent rounding |
|
* errors from causing elapsed vtime to go negative. |
|
*/ |
|
other = account_other_time(delta); |
|
WARN_ON_ONCE(vtime->state == VTIME_INACTIVE); |
|
vtime->starttime += delta; |
|
|
|
return delta - other; |
|
} |
|
|
|
static void vtime_account_system(struct task_struct *tsk, |
|
struct vtime *vtime) |
|
{ |
|
vtime->stime += get_vtime_delta(vtime); |
|
if (vtime->stime >= TICK_NSEC) { |
|
account_system_time(tsk, irq_count(), vtime->stime); |
|
vtime->stime = 0; |
|
} |
|
} |
|
|
|
static void vtime_account_guest(struct task_struct *tsk, |
|
struct vtime *vtime) |
|
{ |
|
vtime->gtime += get_vtime_delta(vtime); |
|
if (vtime->gtime >= TICK_NSEC) { |
|
account_guest_time(tsk, vtime->gtime); |
|
vtime->gtime = 0; |
|
} |
|
} |
|
|
|
static void __vtime_account_kernel(struct task_struct *tsk, |
|
struct vtime *vtime) |
|
{ |
|
/* We might have scheduled out from guest path */ |
|
if (vtime->state == VTIME_GUEST) |
|
vtime_account_guest(tsk, vtime); |
|
else |
|
vtime_account_system(tsk, vtime); |
|
} |
|
|
|
void vtime_account_kernel(struct task_struct *tsk) |
|
{ |
|
struct vtime *vtime = &tsk->vtime; |
|
|
|
if (!vtime_delta(vtime)) |
|
return; |
|
|
|
write_seqcount_begin(&vtime->seqcount); |
|
__vtime_account_kernel(tsk, vtime); |
|
write_seqcount_end(&vtime->seqcount); |
|
} |
|
|
|
void vtime_user_enter(struct task_struct *tsk) |
|
{ |
|
struct vtime *vtime = &tsk->vtime; |
|
|
|
write_seqcount_begin(&vtime->seqcount); |
|
vtime_account_system(tsk, vtime); |
|
vtime->state = VTIME_USER; |
|
write_seqcount_end(&vtime->seqcount); |
|
} |
|
|
|
void vtime_user_exit(struct task_struct *tsk) |
|
{ |
|
struct vtime *vtime = &tsk->vtime; |
|
|
|
write_seqcount_begin(&vtime->seqcount); |
|
vtime->utime += get_vtime_delta(vtime); |
|
if (vtime->utime >= TICK_NSEC) { |
|
account_user_time(tsk, vtime->utime); |
|
vtime->utime = 0; |
|
} |
|
vtime->state = VTIME_SYS; |
|
write_seqcount_end(&vtime->seqcount); |
|
} |
|
|
|
void vtime_guest_enter(struct task_struct *tsk) |
|
{ |
|
struct vtime *vtime = &tsk->vtime; |
|
/* |
|
* The flags must be updated under the lock with |
|
* the vtime_starttime 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(&vtime->seqcount); |
|
vtime_account_system(tsk, vtime); |
|
tsk->flags |= PF_VCPU; |
|
vtime->state = VTIME_GUEST; |
|
write_seqcount_end(&vtime->seqcount); |
|
} |
|
EXPORT_SYMBOL_GPL(vtime_guest_enter); |
|
|
|
void vtime_guest_exit(struct task_struct *tsk) |
|
{ |
|
struct vtime *vtime = &tsk->vtime; |
|
|
|
write_seqcount_begin(&vtime->seqcount); |
|
vtime_account_guest(tsk, vtime); |
|
tsk->flags &= ~PF_VCPU; |
|
vtime->state = VTIME_SYS; |
|
write_seqcount_end(&vtime->seqcount); |
|
} |
|
EXPORT_SYMBOL_GPL(vtime_guest_exit); |
|
|
|
void vtime_account_idle(struct task_struct *tsk) |
|
{ |
|
account_idle_time(get_vtime_delta(&tsk->vtime)); |
|
} |
|
|
|
void vtime_task_switch_generic(struct task_struct *prev) |
|
{ |
|
struct vtime *vtime = &prev->vtime; |
|
|
|
write_seqcount_begin(&vtime->seqcount); |
|
if (vtime->state == VTIME_IDLE) |
|
vtime_account_idle(prev); |
|
else |
|
__vtime_account_kernel(prev, vtime); |
|
vtime->state = VTIME_INACTIVE; |
|
vtime->cpu = -1; |
|
write_seqcount_end(&vtime->seqcount); |
|
|
|
vtime = ¤t->vtime; |
|
|
|
write_seqcount_begin(&vtime->seqcount); |
|
if (is_idle_task(current)) |
|
vtime->state = VTIME_IDLE; |
|
else if (current->flags & PF_VCPU) |
|
vtime->state = VTIME_GUEST; |
|
else |
|
vtime->state = VTIME_SYS; |
|
vtime->starttime = sched_clock(); |
|
vtime->cpu = smp_processor_id(); |
|
write_seqcount_end(&vtime->seqcount); |
|
} |
|
|
|
void vtime_init_idle(struct task_struct *t, int cpu) |
|
{ |
|
struct vtime *vtime = &t->vtime; |
|
unsigned long flags; |
|
|
|
local_irq_save(flags); |
|
write_seqcount_begin(&vtime->seqcount); |
|
vtime->state = VTIME_IDLE; |
|
vtime->starttime = sched_clock(); |
|
vtime->cpu = cpu; |
|
write_seqcount_end(&vtime->seqcount); |
|
local_irq_restore(flags); |
|
} |
|
|
|
u64 task_gtime(struct task_struct *t) |
|
{ |
|
struct vtime *vtime = &t->vtime; |
|
unsigned int seq; |
|
u64 gtime; |
|
|
|
if (!vtime_accounting_enabled()) |
|
return t->gtime; |
|
|
|
do { |
|
seq = read_seqcount_begin(&vtime->seqcount); |
|
|
|
gtime = t->gtime; |
|
if (vtime->state == VTIME_GUEST) |
|
gtime += vtime->gtime + vtime_delta(vtime); |
|
|
|
} while (read_seqcount_retry(&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. |
|
*/ |
|
void task_cputime(struct task_struct *t, u64 *utime, u64 *stime) |
|
{ |
|
struct vtime *vtime = &t->vtime; |
|
unsigned int seq; |
|
u64 delta; |
|
|
|
if (!vtime_accounting_enabled()) { |
|
*utime = t->utime; |
|
*stime = t->stime; |
|
return; |
|
} |
|
|
|
do { |
|
seq = read_seqcount_begin(&vtime->seqcount); |
|
|
|
*utime = t->utime; |
|
*stime = t->stime; |
|
|
|
/* Task is sleeping or idle, nothing to add */ |
|
if (vtime->state < VTIME_SYS) |
|
continue; |
|
|
|
delta = vtime_delta(vtime); |
|
|
|
/* |
|
* Task runs either in user (including guest) or kernel space, |
|
* add pending nohz time to the right place. |
|
*/ |
|
if (vtime->state == VTIME_SYS) |
|
*stime += vtime->stime + delta; |
|
else |
|
*utime += vtime->utime + delta; |
|
} while (read_seqcount_retry(&vtime->seqcount, seq)); |
|
} |
|
|
|
static int vtime_state_fetch(struct vtime *vtime, int cpu) |
|
{ |
|
int state = READ_ONCE(vtime->state); |
|
|
|
/* |
|
* We raced against a context switch, fetch the |
|
* kcpustat task again. |
|
*/ |
|
if (vtime->cpu != cpu && vtime->cpu != -1) |
|
return -EAGAIN; |
|
|
|
/* |
|
* Two possible things here: |
|
* 1) We are seeing the scheduling out task (prev) or any past one. |
|
* 2) We are seeing the scheduling in task (next) but it hasn't |
|
* passed though vtime_task_switch() yet so the pending |
|
* cputime of the prev task may not be flushed yet. |
|
* |
|
* Case 1) is ok but 2) is not. So wait for a safe VTIME state. |
|
*/ |
|
if (state == VTIME_INACTIVE) |
|
return -EAGAIN; |
|
|
|
return state; |
|
} |
|
|
|
static u64 kcpustat_user_vtime(struct vtime *vtime) |
|
{ |
|
if (vtime->state == VTIME_USER) |
|
return vtime->utime + vtime_delta(vtime); |
|
else if (vtime->state == VTIME_GUEST) |
|
return vtime->gtime + vtime_delta(vtime); |
|
return 0; |
|
} |
|
|
|
static int kcpustat_field_vtime(u64 *cpustat, |
|
struct task_struct *tsk, |
|
enum cpu_usage_stat usage, |
|
int cpu, u64 *val) |
|
{ |
|
struct vtime *vtime = &tsk->vtime; |
|
unsigned int seq; |
|
|
|
do { |
|
int state; |
|
|
|
seq = read_seqcount_begin(&vtime->seqcount); |
|
|
|
state = vtime_state_fetch(vtime, cpu); |
|
if (state < 0) |
|
return state; |
|
|
|
*val = cpustat[usage]; |
|
|
|
/* |
|
* Nice VS unnice cputime accounting may be inaccurate if |
|
* the nice value has changed since the last vtime update. |
|
* But proper fix would involve interrupting target on nice |
|
* updates which is a no go on nohz_full (although the scheduler |
|
* may still interrupt the target if rescheduling is needed...) |
|
*/ |
|
switch (usage) { |
|
case CPUTIME_SYSTEM: |
|
if (state == VTIME_SYS) |
|
*val += vtime->stime + vtime_delta(vtime); |
|
break; |
|
case CPUTIME_USER: |
|
if (task_nice(tsk) <= 0) |
|
*val += kcpustat_user_vtime(vtime); |
|
break; |
|
case CPUTIME_NICE: |
|
if (task_nice(tsk) > 0) |
|
*val += kcpustat_user_vtime(vtime); |
|
break; |
|
case CPUTIME_GUEST: |
|
if (state == VTIME_GUEST && task_nice(tsk) <= 0) |
|
*val += vtime->gtime + vtime_delta(vtime); |
|
break; |
|
case CPUTIME_GUEST_NICE: |
|
if (state == VTIME_GUEST && task_nice(tsk) > 0) |
|
*val += vtime->gtime + vtime_delta(vtime); |
|
break; |
|
default: |
|
break; |
|
} |
|
} while (read_seqcount_retry(&vtime->seqcount, seq)); |
|
|
|
return 0; |
|
} |
|
|
|
u64 kcpustat_field(struct kernel_cpustat *kcpustat, |
|
enum cpu_usage_stat usage, int cpu) |
|
{ |
|
u64 *cpustat = kcpustat->cpustat; |
|
u64 val = cpustat[usage]; |
|
struct rq *rq; |
|
int err; |
|
|
|
if (!vtime_accounting_enabled_cpu(cpu)) |
|
return val; |
|
|
|
rq = cpu_rq(cpu); |
|
|
|
for (;;) { |
|
struct task_struct *curr; |
|
|
|
rcu_read_lock(); |
|
curr = rcu_dereference(rq->curr); |
|
if (WARN_ON_ONCE(!curr)) { |
|
rcu_read_unlock(); |
|
return cpustat[usage]; |
|
} |
|
|
|
err = kcpustat_field_vtime(cpustat, curr, usage, cpu, &val); |
|
rcu_read_unlock(); |
|
|
|
if (!err) |
|
return val; |
|
|
|
cpu_relax(); |
|
} |
|
} |
|
EXPORT_SYMBOL_GPL(kcpustat_field); |
|
|
|
static int kcpustat_cpu_fetch_vtime(struct kernel_cpustat *dst, |
|
const struct kernel_cpustat *src, |
|
struct task_struct *tsk, int cpu) |
|
{ |
|
struct vtime *vtime = &tsk->vtime; |
|
unsigned int seq; |
|
|
|
do { |
|
u64 *cpustat; |
|
u64 delta; |
|
int state; |
|
|
|
seq = read_seqcount_begin(&vtime->seqcount); |
|
|
|
state = vtime_state_fetch(vtime, cpu); |
|
if (state < 0) |
|
return state; |
|
|
|
*dst = *src; |
|
cpustat = dst->cpustat; |
|
|
|
/* Task is sleeping, dead or idle, nothing to add */ |
|
if (state < VTIME_SYS) |
|
continue; |
|
|
|
delta = vtime_delta(vtime); |
|
|
|
/* |
|
* Task runs either in user (including guest) or kernel space, |
|
* add pending nohz time to the right place. |
|
*/ |
|
if (state == VTIME_SYS) { |
|
cpustat[CPUTIME_SYSTEM] += vtime->stime + delta; |
|
} else if (state == VTIME_USER) { |
|
if (task_nice(tsk) > 0) |
|
cpustat[CPUTIME_NICE] += vtime->utime + delta; |
|
else |
|
cpustat[CPUTIME_USER] += vtime->utime + delta; |
|
} else { |
|
WARN_ON_ONCE(state != VTIME_GUEST); |
|
if (task_nice(tsk) > 0) { |
|
cpustat[CPUTIME_GUEST_NICE] += vtime->gtime + delta; |
|
cpustat[CPUTIME_NICE] += vtime->gtime + delta; |
|
} else { |
|
cpustat[CPUTIME_GUEST] += vtime->gtime + delta; |
|
cpustat[CPUTIME_USER] += vtime->gtime + delta; |
|
} |
|
} |
|
} while (read_seqcount_retry(&vtime->seqcount, seq)); |
|
|
|
return 0; |
|
} |
|
|
|
void kcpustat_cpu_fetch(struct kernel_cpustat *dst, int cpu) |
|
{ |
|
const struct kernel_cpustat *src = &kcpustat_cpu(cpu); |
|
struct rq *rq; |
|
int err; |
|
|
|
if (!vtime_accounting_enabled_cpu(cpu)) { |
|
*dst = *src; |
|
return; |
|
} |
|
|
|
rq = cpu_rq(cpu); |
|
|
|
for (;;) { |
|
struct task_struct *curr; |
|
|
|
rcu_read_lock(); |
|
curr = rcu_dereference(rq->curr); |
|
if (WARN_ON_ONCE(!curr)) { |
|
rcu_read_unlock(); |
|
*dst = *src; |
|
return; |
|
} |
|
|
|
err = kcpustat_cpu_fetch_vtime(dst, src, curr, cpu); |
|
rcu_read_unlock(); |
|
|
|
if (!err) |
|
return; |
|
|
|
cpu_relax(); |
|
} |
|
} |
|
EXPORT_SYMBOL_GPL(kcpustat_cpu_fetch); |
|
|
|
#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
|
|
|