[PATCH 6/11] Update CPU maps
Nathan Fontenot
nfont at linux.vnet.ibm.com
Sat Mar 9 15:04:40 EST 2013
From: Jesse Larrew <jlarrew at linux.vnet.ibm.com>
Platform events such as partition migration or the new PRRN firmware
feature can cause the NUMA characteristics of a CPU to change, and these
changes will be reflected in the device tree nodes for the affected
CPUs.
This patch registers a handler for Open Firmware device tree updates
and reconfigures the CPU and node maps whenever the associativity
changes. Currently, this is accomplished by marking the affected CPUs in
the cpu_associativity_changes_mask and allowing
arch_update_cpu_topology() to retrieve the new associativity information
using hcall_vphn().
Protecting the NUMA cpu maps from concurrent access during an update
operation will be addressed in a subsequent patch in this series.
Signed-off-by: Nathan Fontenot <nfont at linux.vnet.ibm.com>
---
arch/powerpc/include/asm/prom.h | 1
arch/powerpc/mm/numa.c | 99 ++++++++++++++++++++++++++++++----------
2 files changed, 76 insertions(+), 24 deletions(-)
Index: powerpc/arch/powerpc/include/asm/prom.h
===================================================================
--- powerpc.orig/arch/powerpc/include/asm/prom.h 2013-03-08 19:57:14.000000000 -0600
+++ powerpc/arch/powerpc/include/asm/prom.h 2013-03-08 19:57:38.000000000 -0600
@@ -138,6 +138,7 @@
#define OV5_XCMO 0x0400
#endif
#define OV5_TYPE1_AFFINITY 0x0580 /* Type 1 NUMA affinity */
+#define OV5_PRRN 0x0540 /* Platform Resource Reassignment */
#define OV5_PFO_HW_RNG 0x0E80 /* PFO Random Number Generator */
#define OV5_PFO_HW_842 0x0E40 /* PFO Compression Accelerator */
#define OV5_PFO_HW_ENCR 0x0E20 /* PFO Encryption Accelerator */
Index: powerpc/arch/powerpc/mm/numa.c
===================================================================
--- powerpc.orig/arch/powerpc/mm/numa.c 2013-03-08 19:57:27.000000000 -0600
+++ powerpc/arch/powerpc/mm/numa.c 2013-03-08 19:57:38.000000000 -0600
@@ -1257,7 +1257,8 @@
static u8 vphn_cpu_change_counts[NR_CPUS][MAX_DISTANCE_REF_POINTS];
static cpumask_t cpu_associativity_changes_mask;
static int vphn_enabled;
-static void set_topology_timer(void);
+static int prrn_enabled;
+static void reset_topology_timer(void);
/*
* Store the current values of the associativity change counters in the
@@ -1293,11 +1294,9 @@
*/
static int update_cpu_associativity_changes_mask(void)
{
- int cpu, nr_cpus = 0;
+ int cpu;
cpumask_t *changes = &cpu_associativity_changes_mask;
- cpumask_clear(changes);
-
for_each_possible_cpu(cpu) {
int i, changed = 0;
u8 *counts = vphn_cpu_change_counts[cpu];
@@ -1311,11 +1310,10 @@
}
if (changed) {
cpumask_set_cpu(cpu, changes);
- nr_cpus++;
}
}
- return nr_cpus;
+ return cpumask_weight(changes);
}
/*
@@ -1416,7 +1414,7 @@
unsigned int associativity[VPHN_ASSOC_BUFSIZE] = {0};
struct device *dev;
- for_each_cpu(cpu,&cpu_associativity_changes_mask) {
+ for_each_cpu(cpu, &cpu_associativity_changes_mask) {
vphn_get_associativity(cpu, associativity);
nid = associativity_to_nid(associativity);
@@ -1438,6 +1436,7 @@
dev = get_cpu_device(cpu);
if (dev)
kobject_uevent(&dev->kobj, KOBJ_CHANGE);
+ cpumask_clear_cpu(cpu, &cpu_associativity_changes_mask);
changed = 1;
}
@@ -1457,37 +1456,80 @@
static void topology_timer_fn(unsigned long ignored)
{
- if (!vphn_enabled)
- return;
- if (update_cpu_associativity_changes_mask() > 0)
+ if (prrn_enabled && cpumask_weight(&cpu_associativity_changes_mask))
topology_schedule_update();
- set_topology_timer();
+ else if (vphn_enabled) {
+ if (update_cpu_associativity_changes_mask() > 0)
+ topology_schedule_update();
+ reset_topology_timer();
+ }
}
static struct timer_list topology_timer =
TIMER_INITIALIZER(topology_timer_fn, 0, 0);
-static void set_topology_timer(void)
+static void reset_topology_timer(void)
{
topology_timer.data = 0;
topology_timer.expires = jiffies + 60 * HZ;
- add_timer(&topology_timer);
+ mod_timer(&topology_timer, topology_timer.expires);
+}
+
+static void stage_topology_update(int core_id)
+{
+ cpumask_or(&cpu_associativity_changes_mask,
+ &cpu_associativity_changes_mask, cpu_sibling_mask(core_id));
+ reset_topology_timer();
}
+static int dt_update_callback(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct of_prop_reconfig *update;
+ int rc = NOTIFY_DONE;
+
+ switch (action) {
+ case OF_RECONFIG_ADD_PROPERTY:
+ case OF_RECONFIG_UPDATE_PROPERTY:
+ update = (struct of_prop_reconfig *)data;
+ if (!of_prop_cmp(update->dn->type, "cpu")) {
+ u32 core_id;
+ of_property_read_u32(update->dn, "reg", &core_id);
+ stage_topology_update(core_id);
+ rc = NOTIFY_OK;
+ }
+ break;
+ }
+
+ return rc;
+}
+
+static struct notifier_block dt_update_nb = {
+ .notifier_call = dt_update_callback,
+};
+
/*
- * Start polling for VPHN associativity changes.
+ * Start polling for associativity changes.
*/
int start_topology_update(void)
{
int rc = 0;
- /* Disabled until races with load balancing are fixed */
- if (0 && firmware_has_feature(FW_FEATURE_VPHN) &&
- get_lppaca()->shared_proc) {
- vphn_enabled = 1;
- setup_cpu_associativity_change_counters();
- init_timer_deferrable(&topology_timer);
- set_topology_timer();
- rc = 1;
+ if (platform_has_feature(OV5_PRRN)) {
+ if (!prrn_enabled) {
+ prrn_enabled = 1;
+ vphn_enabled = 0;
+ rc = of_reconfig_notifier_register(&dt_update_nb);
+ }
+ } else if (0 && firmware_has_feature(FW_FEATURE_VPHN) &&
+ get_lppaca()->shared_proc) {
+ /* Disabled until races with load balancing are fixed */
+ if (!vphn_enabled) {
+ prrn_enabled = 0;
+ vphn_enabled = 1;
+ setup_cpu_associativity_change_counters();
+ init_timer_deferrable(&topology_timer);
+ reset_topology_timer();
+ }
}
return rc;
@@ -1499,7 +1541,16 @@
*/
int stop_topology_update(void)
{
- vphn_enabled = 0;
- return del_timer_sync(&topology_timer);
+ int rc = 0;
+
+ if (prrn_enabled) {
+ prrn_enabled = 0;
+ rc = of_reconfig_notifier_unregister(&dt_update_nb);
+ } else if (vphn_enabled) {
+ vphn_enabled = 0;
+ rc = del_timer_sync(&topology_timer);
+ }
+
+ return rc;
}
#endif /* CONFIG_PPC_SPLPAR */
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