sched: Fix the irqtime code to deal with u64 wraps (fe44d621) · Commits · 戴 / test

kernel/sched.c

+50 −33

Original line number	Diff line number	Diff line
		@@ -636,23 +636,18 @@ static inline struct task_group task_group(struct task_struct p)

		#endif /* CONFIG_CGROUP_SCHED */

		static u64 irq_time_cpu(int cpu);
		static void sched_irq_time_avg_update(struct rq *rq, u64 irq_time);
		static void update_rq_clock_task(struct rq *rq, s64 delta);

		inline void update_rq_clock(struct rq *rq)
		static void update_rq_clock(struct rq *rq)
		{
		int cpu = cpu_of(rq);
		u64 irq_time;
		s64 delta;

		if (rq->skip_clock_update)
		return;

		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;

		sched_irq_time_avg_update(rq, irq_time);
		delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
		rq->clock += delta;
		update_rq_clock_task(rq, delta);
		}

		/*
		@@ -1946,19 +1941,20 @@ void disable_sched_clock_irqtime(void)
		sched_clock_irqtime = 0;
		}

		static u64 irq_time_cpu(int cpu)
		static inline 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);
		}

		/*
		* Called before incrementing preempt_count on {soft,}irq_enter
		* and before decrementing preempt_count on {soft,}irq_exit.
		*/
		void account_system_vtime(struct task_struct *curr)
		{
		unsigned long flags;
		s64 delta;
		int cpu;
		u64 now, delta;

		if (!sched_clock_irqtime)
		return;
		@@ -1966,9 +1962,9 @@ void account_system_vtime(struct task_struct *curr)
		local_irq_save(flags);

		cpu = smp_processor_id();
		now = sched_clock_cpu(cpu);
		delta = now - per_cpu(irq_start_time, cpu);
		per_cpu(irq_start_time, cpu) = now;
		delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time);
		__this_cpu_add(irq_start_time, delta);

		/*
		* We do not account for softirq time from ksoftirqd here.
		* We want to continue accounting softirq time to ksoftirqd thread
		@@ -1976,33 +1972,54 @@ void account_system_vtime(struct task_struct *curr)
		* that do not consume any time, but still wants to run.
		*/
		if (hardirq_count())
		per_cpu(cpu_hardirq_time, cpu) += delta;
		__this_cpu_add(cpu_hardirq_time, delta);
		else if (in_serving_softirq() && !(curr->flags & PF_KSOFTIRQD))
		per_cpu(cpu_softirq_time, cpu) += delta;
		__this_cpu_add(cpu_softirq_time, delta);

		local_irq_restore(flags);
		}
		EXPORT_SYMBOL_GPL(account_system_vtime);

		static void sched_irq_time_avg_update(struct rq *rq, u64 curr_irq_time)
		static void update_rq_clock_task(struct rq *rq, s64 delta)
		{
		if (sched_clock_irqtime && sched_feat(NONIRQ_POWER)) {
		u64 delta_irq = curr_irq_time - rq->prev_irq_time;
		rq->prev_irq_time = curr_irq_time;
		sched_rt_avg_update(rq, delta_irq);
		}
		s64 irq_delta;

		irq_delta = irq_time_cpu(cpu_of(rq)) - rq->prev_irq_time;

		/*
		* Since irq_time is only updated on {soft,}irq_exit, we might run into
		* this case when a previous update_rq_clock() happened inside a
		* {soft,}irq region.
		*
		* When this happens, we stop ->clock_task and only update the
		* prev_irq_time stamp to account for the part that fit, so that a next
		* update will consume the rest. This ensures ->clock_task is
		* monotonic.
		*
		* It does however cause some slight miss-attribution of {soft,}irq
		* time, a more accurate solution would be to update the irq_time using
		* the current rq->clock timestamp, except that would require using
		* atomic ops.
		*/
		if (irq_delta > delta)
		irq_delta = delta;

		rq->prev_irq_time += irq_delta;
		delta -= irq_delta;
		rq->clock_task += delta;

		if (irq_delta && sched_feat(NONIRQ_POWER))
		sched_rt_avg_update(rq, irq_delta);
		}

		#else
		#else /* CONFIG_IRQ_TIME_ACCOUNTING */

		static u64 irq_time_cpu(int cpu)
		static void update_rq_clock_task(struct rq *rq, s64 delta)
		{
		return 0;
		rq->clock_task += delta;
		}

		static void sched_irq_time_avg_update(struct rq *rq, u64 curr_irq_time) { }

		#endif
		#endif /* CONFIG_IRQ_TIME_ACCOUNTING */

		#include "sched_idletask.c"
		#include "sched_fair.c"

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