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Commit cee5405d authored by Michael Bringmann's avatar Michael Bringmann Committed by Michael Ellerman
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powerpc/hotplug: Improve responsiveness of hotplug change 



powerpc/hotplug: On Power systems with shared configurations of CPUs
and memory, there are some issues with the association of additional
CPUs and memory to nodes when hot-adding resources.  During hotplug
CPU operations, this patch resets the timer on topology update work
function to a small value to better ensure that the CPU topology is
detected and configured sooner.

Signed-off-by: default avatarMichael Bringmann <mwb@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent a3496e91

arch/powerpc/include/asm/topology.h

+8 −0
Original line number Diff line number Diff line
@@ -96,6 +96,14 @@ static inline int prrn_is_enabled(void) 
}

#endif /* CONFIG_NUMA && CONFIG_PPC_SPLPAR */



#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_NEED_MULTIPLE_NODES)

#if defined(CONFIG_PPC_SPLPAR)

extern int timed_topology_update(int nsecs);

#else

#define	timed_topology_update(nsecs)

#endif /* CONFIG_PPC_SPLPAR */

#endif /* CONFIG_HOTPLUG_CPU || CONFIG_NEED_MULTIPLE_NODES */



#include <asm-generic/topology.h>



#ifdef CONFIG_SMP

arch/powerpc/mm/numa.c

+22 −1
Original line number Diff line number Diff line
@@ -1148,14 +1148,34 @@ struct topology_update_data { 
	int new_nid;

};



#define TOPOLOGY_DEF_TIMER_SECS	60



static u8 vphn_cpu_change_counts[NR_CPUS][MAX_DISTANCE_REF_POINTS];

static cpumask_t cpu_associativity_changes_mask;

static int vphn_enabled;

static int prrn_enabled;

static void reset_topology_timer(void);

static int topology_timer_secs = 1;

static int topology_inited;

static int topology_update_needed;



/*

 * Change polling interval for associativity changes.

 */

int timed_topology_update(int nsecs)

{

	if (vphn_enabled) {

		if (nsecs > 0)

			topology_timer_secs = nsecs;

		else

			topology_timer_secs = TOPOLOGY_DEF_TIMER_SECS;



		reset_topology_timer();

	}



	return 0;

}



/*

 * Store the current values of the associativity change counters in the

 * hypervisor.
@@ -1251,6 +1271,7 @@ static long vphn_get_associativity(unsigned long cpu, 
		break;

	case H_SUCCESS:

		dbg("VPHN hcall succeeded. Reset polling...\n");

		timed_topology_update(0);

		break;

	}
@@ -1481,7 +1502,7 @@ static struct timer_list topology_timer = 
static void reset_topology_timer(void)

{

	topology_timer.data = 0;

	topology_timer.expires = jiffies + 60 * HZ;

	topology_timer.expires = jiffies + topology_timer_secs * HZ;

	mod_timer(&topology_timer, topology_timer.expires);

}

arch/powerpc/platforms/pseries/hotplug-cpu.c

+2 −0
Original line number Diff line number Diff line
@@ -363,6 +363,7 @@ static int dlpar_online_cpu(struct device_node *dn) 
			BUG_ON(get_cpu_current_state(cpu)

					!= CPU_STATE_OFFLINE);

			cpu_maps_update_done();

			timed_topology_update(1);

			rc = device_online(get_cpu_device(cpu));

			if (rc)

				goto out;
@@ -533,6 +534,7 @@ static int dlpar_offline_cpu(struct device_node *dn) 
				set_preferred_offline_state(cpu,

							    CPU_STATE_OFFLINE);

				cpu_maps_update_done();

				timed_topology_update(1);

				rc = device_offline(get_cpu_device(cpu));

				if (rc)

					goto out;