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Commit d68bddb7 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
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[S390] topology: increase poll frequency if change is anticipated 



Increase cpu topology change poll frequency if a change is anticipated.
Otherwise a user might be a bit confused to have to wait up to a minute
in order to see a change this should be visible immediatly.
However there is no guarantee that the change will happen during the
time frame the poll frequency is increased.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent c5328901

arch/s390/include/asm/topology.h

+2 −0
Original line number Diff line number Diff line
@@ -35,11 +35,13 @@ int topology_cpu_init(struct cpu *); 
int topology_set_cpu_management(int fc);

void topology_schedule_update(void);

void store_topology(struct sysinfo_15_1_x *info);

void topology_expect_change(void);



#else /* CONFIG_SCHED_BOOK */



static inline void topology_schedule_update(void) { }

static inline int topology_cpu_init(struct cpu *cpu) { return 0; }

static inline void topology_expect_change(void) { }



#endif /* CONFIG_SCHED_BOOK */

arch/s390/kernel/smp.c

+2 −0
Original line number Diff line number Diff line
@@ -867,6 +867,7 @@ static ssize_t cpu_configure_store(struct sys_device *dev, 
			if (!rc) {

				smp_cpu_state[cpu] = CPU_STATE_STANDBY;

				cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);

				topology_expect_change();

			}

		}

		break;
@@ -876,6 +877,7 @@ static ssize_t cpu_configure_store(struct sys_device *dev, 
			if (!rc) {

				smp_cpu_state[cpu] = CPU_STATE_CONFIGURED;

				cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);

				topology_expect_change();

			}

		}

		break;

arch/s390/kernel/topology.c

+26 −8
Original line number Diff line number Diff line
@@ -31,7 +31,6 @@ struct mask_info { 
static int topology_enabled = 1;

static void topology_work_fn(struct work_struct *work);

static struct sysinfo_15_1_x *tl_info;

static struct timer_list topology_timer;

static void set_topology_timer(void);

static DECLARE_WORK(topology_work, topology_work_fn);

/* topology_lock protects the core linked list */
@@ -297,12 +296,30 @@ static void topology_timer_fn(unsigned long ignored) 
	set_topology_timer();

}



static struct timer_list topology_timer =

	TIMER_DEFERRED_INITIALIZER(topology_timer_fn, 0, 0);



static atomic_t topology_poll = ATOMIC_INIT(0);



static void set_topology_timer(void)

{

	topology_timer.function = topology_timer_fn;

	topology_timer.data = 0;

	topology_timer.expires = jiffies + 60 * HZ;

	add_timer(&topology_timer);

	if (atomic_add_unless(&topology_poll, -1, 0))

		mod_timer(&topology_timer, jiffies + HZ / 10);

	else

		mod_timer(&topology_timer, jiffies + HZ * 60);

}



void topology_expect_change(void)

{

	if (!MACHINE_HAS_TOPOLOGY)

		return;

	/* This is racy, but it doesn't matter since it is just a heuristic.

	 * Worst case is that we poll in a higher frequency for a bit longer.

	 */

	if (atomic_read(&topology_poll) > 60)

		return;

	atomic_add(60, &topology_poll);

	set_topology_timer();

}



static int __init early_parse_topology(char *p)
@@ -379,8 +396,10 @@ static ssize_t dispatching_store(struct sysdev_class *dev, 
	if (cpu_management == val)

		goto out;

	rc = topology_set_cpu_management(val);

	if (!rc)

	if (rc)

		goto out;

	cpu_management = val;

	topology_expect_change();

out:

	mutex_unlock(&smp_cpu_state_mutex);

	put_online_cpus();
@@ -438,7 +457,6 @@ static int __init topology_init(void) 
		topology_update_polarization_simple();

		goto out;

	}

	init_timer_deferrable(&topology_timer);

	set_topology_timer();

out:

	update_cpu_core_map();