Merge "smp/hotplug: Move unparking of percpu threads to the control CPU" (17e81682) · Commits · e / devices / android_kernel_fairphone_FP3

kernel/cpu.c

+18 −18

Original line number	Diff line number	Diff line
		@@ -409,12 +409,25 @@ static int notify_online(unsigned int cpu)
		cpu_notify(CPU_ONLINE, cpu);
		return 0;
		}
		static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st);

		static int bringup_wait_for_ap(unsigned int cpu)
		{
		struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);

		/* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */
		wait_for_completion(&st->done);
		BUG_ON(!cpu_online(cpu));

		/* Unpark the stopper thread and the hotplug thread of the target cpu */
		stop_machine_unpark(cpu);
		kthread_unpark(st->thread);

		/* Should we go further up ? */
		if (st->target > CPUHP_AP_ONLINE_IDLE) {
		__cpuhp_kick_ap_work(st);
		wait_for_completion(&st->done);
		}
		return st->result;
		}

		@@ -437,9 +450,7 @@ static int bringup_cpu(unsigned int cpu)
		cpu_notify(CPU_UP_CANCELED, cpu);
		return ret;
		}
		ret = bringup_wait_for_ap(cpu);
		BUG_ON(!cpu_online(cpu));
		return ret;
		return bringup_wait_for_ap(cpu);
		}

		/*
		@@ -979,30 +990,19 @@ void notify_cpu_starting(unsigned int cpu)
		}

		/*
		* Called from the idle task. We need to set active here, so we can kick off
		* the stopper thread and unpark the smpboot threads. If the target state is
		* beyond CPUHP_AP_ONLINE_IDLE we kick cpuhp thread and let it bring up the
		* cpu further.
		* Called from the idle task. Wake up the controlling task which brings the
		* stopper and the hotplug thread of the upcoming CPU up and then delegates
		* the rest of the online bringup to the hotplug thread.
		*/
		void cpuhp_online_idle(enum cpuhp_state state)
		{
		struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
		unsigned int cpu = smp_processor_id();

		/* Happens for the boot cpu */
		if (state != CPUHP_AP_ONLINE_IDLE)
		return;

		st->state = CPUHP_AP_ONLINE_IDLE;

		/* Unpark the stopper thread and the hotplug thread of this cpu */
		stop_machine_unpark(cpu);
		kthread_unpark(st->thread);

		/* Should we go further up ? */
		if (st->target > CPUHP_AP_ONLINE_IDLE)
		__cpuhp_kick_ap_work(st);
		else
		complete(&st->done);
		}