diff options
Diffstat (limited to 'kernel/sched/cputime.c')
| -rw-r--r-- | kernel/sched/cputime.c | 43 |
1 files changed, 17 insertions, 26 deletions
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index af7952f12e6c..6dab4854c6c0 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -14,15 +14,15 @@ * They are only modified in vtime_account, on corresponding CPU * with interrupts disabled. So, writes are safe. * They are read and saved off onto struct rq in update_rq_clock(). - * This may result in other CPU reading this CPU's irq time and can + * This may result in other CPU reading this CPU's IRQ time and can * race with irq/vtime_account on this CPU. We would either get old - * or new value with a side effect of accounting a slice of irq time to wrong - * task when irq is in progress while we read rq->clock. That is a worthy - * compromise in place of having locks on each irq in account_system_time. + * or new value with a side effect of accounting a slice of IRQ time to wrong + * task when IRQ is in progress while we read rq->clock. That is a worthy + * compromise in place of having locks on each IRQ in account_system_time. */ DEFINE_PER_CPU(struct irqtime, cpu_irqtime); -static int sched_clock_irqtime; +int sched_clock_irqtime; void enable_sched_clock_irqtime(void) { @@ -57,7 +57,7 @@ void irqtime_account_irq(struct task_struct *curr, unsigned int offset) s64 delta; int cpu; - if (!sched_clock_irqtime) + if (!irqtime_enabled()) return; cpu = smp_processor_id(); @@ -90,8 +90,6 @@ static u64 irqtime_tick_accounted(u64 maxtime) #else /* CONFIG_IRQ_TIME_ACCOUNTING */ -#define sched_clock_irqtime (0) - static u64 irqtime_tick_accounted(u64 dummy) { return 0; @@ -269,7 +267,7 @@ static __always_inline u64 steal_account_process_time(u64 maxtime) } /* - * Account how much elapsed time was spent in steal, irq, or softirq time. + * Account how much elapsed time was spent in steal, IRQ, or softirq time. */ static inline u64 account_other_time(u64 max) { @@ -370,7 +368,7 @@ void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times) * Check for hardirq is done both for system and user time as there is * no timer going off while we are on hardirq and hence we may never get an * opportunity to update it solely in system time. - * p->stime and friends are only updated on system time and not on irq + * p->stime and friends are only updated on system time and not on IRQ * softirq as those do not count in task exec_runtime any more. */ static void irqtime_account_process_tick(struct task_struct *p, int user_tick, @@ -380,7 +378,7 @@ static void irqtime_account_process_tick(struct task_struct *p, int user_tick, /* * When returning from idle, many ticks can get accounted at - * once, including some ticks of steal, irq, and softirq time. + * once, including some ticks of steal, IRQ, and softirq time. * Subtract those ticks from the amount of time accounted to * idle, or potentially user or system time. Due to rounding, * other time can exceed ticks occasionally. @@ -424,19 +422,6 @@ static inline void irqtime_account_process_tick(struct task_struct *p, int user_ */ #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE -# ifndef __ARCH_HAS_VTIME_TASK_SWITCH -void vtime_task_switch(struct task_struct *prev) -{ - if (is_idle_task(prev)) - vtime_account_idle(prev); - else - vtime_account_kernel(prev); - - vtime_flush(prev); - arch_vtime_task_switch(prev); -} -# endif - void vtime_account_irq(struct task_struct *tsk, unsigned int offset) { unsigned int pc = irq_count() - offset; @@ -491,7 +476,7 @@ void account_process_tick(struct task_struct *p, int user_tick) if (vtime_accounting_enabled_this_cpu()) return; - if (sched_clock_irqtime) { + if (irqtime_enabled()) { irqtime_account_process_tick(p, user_tick, 1); return; } @@ -520,7 +505,7 @@ void account_idle_ticks(unsigned long ticks) { u64 cputime, steal; - if (sched_clock_irqtime) { + if (irqtime_enabled()) { irqtime_account_idle_ticks(ticks); return; } @@ -595,6 +580,12 @@ void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev, } stime = mul_u64_u64_div_u64(stime, rtime, stime + utime); + /* + * Because mul_u64_u64_div_u64() can approximate on some + * achitectures; enforce the constraint that: a*b/(b+c) <= a. + */ + if (unlikely(stime > rtime)) + stime = rtime; update: /* |