sched/deadline: Optimize sched_dl_global_validate() (26762423) · Commits · 戴 / test

kernel/sched/deadline.c

+32 −7

Original line number	Diff line number	Diff line
		@@ -97,6 +97,17 @@ static inline unsigned long dl_bw_capacity(int i)
		return __dl_bw_capacity(i);
		}
		}

		static inline bool dl_bw_visited(int cpu, u64 gen)
		{
		struct root_domain *rd = cpu_rq(cpu)->rd;

		if (rd->visit_gen == gen)
		return true;

		rd->visit_gen = gen;
		return false;
		}
		#else
		static inline struct dl_bw *dl_bw_of(int i)
		{
		@@ -112,6 +123,11 @@ static inline unsigned long dl_bw_capacity(int i)
		{
		return SCHED_CAPACITY_SCALE;
		}

		static inline bool dl_bw_visited(int cpu, u64 gen)
		{
		return false;
		}
		#endif

		static inline
		@@ -2535,11 +2551,15 @@ const struct sched_class dl_sched_class
		.update_curr = update_curr_dl,
		};

		/* Used for dl_bw check and update, used under sched_rt_handler()::mutex */
		static u64 dl_generation;

		int sched_dl_global_validate(void)
		{
		u64 runtime = global_rt_runtime();
		u64 period = global_rt_period();
		u64 new_bw = to_ratio(period, runtime);
		u64 gen = ++dl_generation;
		struct dl_bw *dl_b;
		int cpu, ret = 0;
		unsigned long flags;
		@@ -2548,13 +2568,13 @@ int sched_dl_global_validate(void)
		* Here we want to check the bandwidth not being set to some
		* value smaller than the currently allocated bandwidth in
		* any of the root_domains.
		*
		* FIXME: Cycling on all the CPUs is overdoing, but simpler than
		* cycling on root_domains... Discussion on different/better
		* solutions is welcome!
		*/
		for_each_possible_cpu(cpu) {
		rcu_read_lock_sched();

		if (dl_bw_visited(cpu, gen))
		goto next;

		dl_b = dl_bw_of(cpu);

		raw_spin_lock_irqsave(&dl_b->lock, flags);
		@@ -2562,6 +2582,7 @@ int sched_dl_global_validate(void)
		ret = -EBUSY;
		raw_spin_unlock_irqrestore(&dl_b->lock, flags);

		next:
		rcu_read_unlock_sched();

		if (ret)
		@@ -2587,6 +2608,7 @@ static void init_dl_rq_bw_ratio(struct dl_rq *dl_rq)
		void sched_dl_do_global(void)
		{
		u64 new_bw = -1;
		u64 gen = ++dl_generation;
		struct dl_bw *dl_b;
		int cpu;
		unsigned long flags;
		@@ -2597,11 +2619,14 @@ void sched_dl_do_global(void)
		if (global_rt_runtime() != RUNTIME_INF)
		new_bw = to_ratio(global_rt_period(), global_rt_runtime());

		/*
		* FIXME: As above...
		*/
		for_each_possible_cpu(cpu) {
		rcu_read_lock_sched();

		if (dl_bw_visited(cpu, gen)) {
		rcu_read_unlock_sched();
		continue;
		}

		dl_b = dl_bw_of(cpu);

		raw_spin_lock_irqsave(&dl_b->lock, flags);

kernel/sched/sched.h

+9 −0

Original line number	Diff line number	Diff line
		@@ -801,6 +801,15 @@ struct root_domain {
		struct dl_bw dl_bw;
		struct cpudl cpudl;

		/*
		* Indicate whether a root_domain's dl_bw has been checked or
		* updated. It's monotonously increasing value.
		*
		* Also, some corner cases, like 'wrap around' is dangerous, but given
		* that u64 is 'big enough'. So that shouldn't be a concern.
		*/
		u64 visit_gen;

		#ifdef HAVE_RT_PUSH_IPI
		/*
		* For IPI pull requests, loop across the rto_mask.

kernel/sched/topology.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -516,6 +516,7 @@ static int init_rootdomain(struct root_domain *rd)
		init_irq_work(&rd->rto_push_work, rto_push_irq_work_func);
		#endif

		rd->visit_gen = 0;
		init_dl_bw(&rd->dl_bw);
		if (cpudl_init(&rd->cpudl) != 0)
		goto free_rto_mask;

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