diff options
| -rw-r--r-- | kernel/sched.c | 43 | ||||
| -rw-r--r-- | kernel/sched_fair.c | 6 | ||||
| -rw-r--r-- | kernel/sched_rt.c | 8 |
3 files changed, 47 insertions, 10 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 9b302e35579..9e01b7100ef 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -491,6 +491,7 @@ struct rq { struct mm_struct *prev_mm; u64 clock; + u64 clock_task; atomic_t nr_iowait; @@ -641,10 +642,19 @@ static inline struct task_group *task_group(struct task_struct *p) #endif /* CONFIG_CGROUP_SCHED */ +static u64 irq_time_cpu(int cpu); + inline void update_rq_clock(struct rq *rq) { - if (!rq->skip_clock_update) - rq->clock = sched_clock_cpu(cpu_of(rq)); + if (!rq->skip_clock_update) { + int cpu = cpu_of(rq); + u64 irq_time; + + rq->clock = sched_clock_cpu(cpu); + irq_time = irq_time_cpu(cpu); + if (rq->clock - irq_time > rq->clock_task) + rq->clock_task = rq->clock - irq_time; + } } /* @@ -1910,6 +1920,18 @@ static void deactivate_task(struct rq *rq, struct task_struct *p, int flags) #ifdef CONFIG_IRQ_TIME_ACCOUNTING +/* + * There are no locks covering percpu hardirq/softirq time. + * They are only modified in account_system_vtime, 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 + * race with irq/account_system_vtime on this CPU. We would either get old + * or new value (or semi updated value on 32 bit) 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. + */ static DEFINE_PER_CPU(u64, cpu_hardirq_time); static DEFINE_PER_CPU(u64, cpu_softirq_time); @@ -1926,6 +1948,14 @@ void disable_sched_clock_irqtime(void) sched_clock_irqtime = 0; } +static u64 irq_time_cpu(int cpu) +{ + if (!sched_clock_irqtime) + return 0; + + return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu); +} + void account_system_vtime(struct task_struct *curr) { unsigned long flags; @@ -1955,6 +1985,13 @@ void account_system_vtime(struct task_struct *curr) local_irq_restore(flags); } +#else + +static u64 irq_time_cpu(int cpu) +{ + return 0; +} + #endif #include "sched_idletask.c" @@ -3322,7 +3359,7 @@ static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) if (task_current(rq, p)) { update_rq_clock(rq); - ns = rq->clock - p->se.exec_start; + ns = rq->clock_task - p->se.exec_start; if ((s64)ns < 0) ns = 0; } diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index f1c615ff39d..c358d4081b8 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -519,7 +519,7 @@ __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr, static void update_curr(struct cfs_rq *cfs_rq) { struct sched_entity *curr = cfs_rq->curr; - u64 now = rq_of(cfs_rq)->clock; + u64 now = rq_of(cfs_rq)->clock_task; unsigned long delta_exec; if (unlikely(!curr)) @@ -602,7 +602,7 @@ update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se) /* * We are starting a new run period: */ - se->exec_start = rq_of(cfs_rq)->clock; + se->exec_start = rq_of(cfs_rq)->clock_task; } /************************************************** @@ -1802,7 +1802,7 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, * 2) too many balance attempts have failed. */ - tsk_cache_hot = task_hot(p, rq->clock, sd); + tsk_cache_hot = task_hot(p, rq->clock_task, sd); if (!tsk_cache_hot || sd->nr_balance_failed > sd->cache_nice_tries) { #ifdef CONFIG_SCHEDSTATS diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index ab77aa00b7b..bea7d79f7e9 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -609,7 +609,7 @@ static void update_curr_rt(struct rq *rq) if (!task_has_rt_policy(curr)) return; - delta_exec = rq->clock - curr->se.exec_start; + delta_exec = rq->clock_task - curr->se.exec_start; if (unlikely((s64)delta_exec < 0)) delta_exec = 0; @@ -618,7 +618,7 @@ static void update_curr_rt(struct rq *rq) curr->se.sum_exec_runtime += delta_exec; account_group_exec_runtime(curr, delta_exec); - curr->se.exec_start = rq->clock; + curr->se.exec_start = rq->clock_task; cpuacct_charge(curr, delta_exec); sched_rt_avg_update(rq, delta_exec); @@ -1075,7 +1075,7 @@ static struct task_struct *_pick_next_task_rt(struct rq *rq) } while (rt_rq); p = rt_task_of(rt_se); - p->se.exec_start = rq->clock; + p->se.exec_start = rq->clock_task; return p; } @@ -1713,7 +1713,7 @@ static void set_curr_task_rt(struct rq *rq) { struct task_struct *p = rq->curr; - p->se.exec_start = rq->clock; + p->se.exec_start = rq->clock_task; /* The running task is never eligible for pushing */ dequeue_pushable_task(rq, p); |