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Code Issues Releases Wiki Activity

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: Michael Bringmann <mwb@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Michael Bringmann 2017-09-08 15:47:47 -05:00 committed by Michael Ellerman
parent a3496e9137
commit cee5405da4
3 changed files with 32 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
arch/powerpc/include/asm/topology.h
View File

@ -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

23
arch/powerpc/mm/numa.c
View File

@ -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);
}

2
arch/powerpc/platforms/pseries/hotplug-cpu.c
View File

@ -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;