sched/deadline: Add dl_bw_capacity() (fc9dc698) · Commits · 戴 / test

Capacity-aware SCHED_DEADLINE Admission Control (AC) needs root domain (rd) CPU capacity sum. Introduce dl_bw_capacity() which for a symmetric rd w/ a CPU capacity of SCHED_CAPACITY_SCALE simply relies on dl_bw_cpus() to return #CPUs multiplied by SCHED_CAPACITY_SCALE. For an asymmetric rd or a CPU capacity < SCHED_CAPACITY_SCALE it computes the CPU capacity sum over rd span and cpu_active_mask. A 'XXX Fix:' comment was added to highlight that if 'rq->rd == def_root_domain' AC should be performed against the capacity of the CPU the task is running on rather the rd CPU capacity sum. This issue already exists w/o capacity awareness. Signed-off-by:

Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:

Juri Lelli <juri.lelli@redhat.com> Link: https://lkml.kernel.org/r/20200520134243.19352-3-dietmar.eggemann@arm.com

kernel/sched/deadline.c

+33 −0

Original line number	Diff line number	Diff line
		@@ -69,6 +69,34 @@ static inline int dl_bw_cpus(int i)

		return cpus;
		}

		static inline unsigned long __dl_bw_capacity(int i)
		{
		struct root_domain *rd = cpu_rq(i)->rd;
		unsigned long cap = 0;

		RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(),
		"sched RCU must be held");

		for_each_cpu_and(i, rd->span, cpu_active_mask)
		cap += capacity_orig_of(i);

		return cap;
		}

		/*
		* XXX Fix: If 'rq->rd == def_root_domain' perform AC against capacity
		* of the CPU the task is running on rather rd's \Sum CPU capacity.
		*/
		static inline unsigned long dl_bw_capacity(int i)
		{
		if (!static_branch_unlikely(&sched_asym_cpucapacity) &&
		capacity_orig_of(i) == SCHED_CAPACITY_SCALE) {
		return dl_bw_cpus(i) << SCHED_CAPACITY_SHIFT;
		} else {
		return __dl_bw_capacity(i);
		}
		}
		#else
		static inline struct dl_bw *dl_bw_of(int i)
		{
		@@ -79,6 +107,11 @@ static inline int dl_bw_cpus(int i)
		{
		return 1;
		}

		static inline unsigned long dl_bw_capacity(int i)
		{
		return SCHED_CAPACITY_SCALE;
		}
		#endif

		static inline

Admin message