xen: support runqueue steal time on xen (6ba286ad) · Commits · 戴 / test

drivers/xen/time.c

+23 −17

Original line number	Diff line number	Diff line
		@@ -47,27 +47,31 @@ static u64 get64(const u64 *p)
		return ret;
		}

		/*
		* Runstate accounting
		*/
		void xen_get_runstate_snapshot(struct vcpu_runstate_info *res)
		static void xen_get_runstate_snapshot_cpu(struct vcpu_runstate_info *res,
		unsigned int cpu)
		{
		u64 state_time;
		struct vcpu_runstate_info *state;

		BUG_ON(preemptible());

		state = this_cpu_ptr(&xen_runstate);
		state = per_cpu_ptr(&xen_runstate, cpu);

		/*
		* The runstate info is always updated by the hypervisor on
		* the current CPU, so there's no need to use anything
		* stronger than a compiler barrier when fetching it.
		*/
		do {
		state_time = get64(&state->state_entry_time);
		rmb(); /* Hypervisor might update data. */
		res = READ_ONCE(state);
		} while (get64(&state->state_entry_time) != state_time);
		rmb(); /* Hypervisor might update data. */
		} while (get64(&state->state_entry_time) != state_time \|\|
		(state_time & XEN_RUNSTATE_UPDATE));
		}

		/*
		* Runstate accounting
		*/
		void xen_get_runstate_snapshot(struct vcpu_runstate_info *res)
		{
		xen_get_runstate_snapshot_cpu(res, smp_processor_id());
		}

		/* return true when a vcpu could run but has no real cpu to run on */
		@@ -80,8 +84,7 @@ static u64 xen_steal_clock(int cpu)
		{
		struct vcpu_runstate_info state;

		BUG_ON(cpu != smp_processor_id());
		xen_get_runstate_snapshot(&state);
		xen_get_runstate_snapshot_cpu(&state, cpu);
		return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline];
		}

		@@ -98,11 +101,14 @@ void xen_setup_runstate_info(int cpu)

		void __init xen_time_setup_guest(void)
		{
		bool xen_runstate_remote;

		xen_runstate_remote = !HYPERVISOR_vm_assist(VMASST_CMD_enable,
		VMASST_TYPE_runstate_update_flag);

		pv_time_ops.steal_clock = xen_steal_clock;

		static_key_slow_inc(&paravirt_steal_enabled);
		/*
		* We can't set paravirt_steal_rq_enabled as this would require the
		* capability to read another cpu's runstate info.
		*/
		if (xen_runstate_remote)
		static_key_slow_inc(&paravirt_steal_rq_enabled);
		}

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