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powerpc/numa: Only use active VPHN count fields
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VPHN supports up to 8 distance fields but the number of entries in
ibm,associativity-reference-points signifies how many are in use.
Don't look at all the VPHN counts, only distance_ref_points_depth
worth.

Since we already cap our distance metrics at MAX_DISTANCE_REF_POINTS,
use that to size the VPHN arrays and add a BUILD_BUG_ON to avoid it growing
larger than the VPHN maximum of 8.

Signed-off-by: Anton Blanchard <[email protected]>
Signed-off-by: Benjamin Herrenschmidt <[email protected]>
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antonblanchard authored and ozbenh committed Feb 7, 2011
1 parent cd9d6cc commit 5de1669
Showing 1 changed file with 6 additions and 4 deletions.
10 changes: 6 additions & 4 deletions arch/powerpc/mm/numa.c
Original file line number Diff line number Diff line change
Expand Up @@ -1291,8 +1291,7 @@ u64 memory_hotplug_max(void)

/* Virtual Processor Home Node (VPHN) support */
#ifdef CONFIG_PPC_SPLPAR
#define VPHN_NR_CHANGE_CTRS (8)
static u8 vphn_cpu_change_counts[NR_CPUS][VPHN_NR_CHANGE_CTRS];
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);
Expand All @@ -1305,12 +1304,15 @@ static void setup_cpu_associativity_change_counters(void)
{
int cpu;

/* The VPHN feature supports a maximum of 8 reference points */
BUILD_BUG_ON(MAX_DISTANCE_REF_POINTS > 8);

for_each_possible_cpu(cpu) {
int i;
u8 *counts = vphn_cpu_change_counts[cpu];
volatile u8 *hypervisor_counts = lppaca[cpu].vphn_assoc_counts;

for (i = 0; i < VPHN_NR_CHANGE_CTRS; i++)
for (i = 0; i < distance_ref_points_depth; i++)
counts[i] = hypervisor_counts[i];
}
}
Expand Down Expand Up @@ -1338,7 +1340,7 @@ static int update_cpu_associativity_changes_mask(void)
u8 *counts = vphn_cpu_change_counts[cpu];
volatile u8 *hypervisor_counts = lppaca[cpu].vphn_assoc_counts;

for (i = 0; i < VPHN_NR_CHANGE_CTRS; i++) {
for (i = 0; i < distance_ref_points_depth; i++) {
if (hypervisor_counts[i] > counts[i]) {
counts[i] = hypervisor_counts[i];
changed = 1;
Expand Down

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