Introduce a per-cpu variable to keep the number of HT siblings of a cpu.
This will be used for quick lookup in select_idle_cpu to determine the
limits of search. This patch does it only for x86.
Signed-off-by: subhra mazumdar <subhra.mazum...@oracle.com>
---
arch/x86/include/asm/smp.h | 1 +
arch/x86/include/asm/topology.h | 1 +
arch/x86/kernel/smpboot.c | 17 ++++++++++++++++-
include/linux/topology.h | 4 ++++
4 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index da545df..1e90cbd 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -22,6 +22,7 @@ extern int smp_num_siblings;
extern unsigned int num_processors;
DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map);
+DECLARE_PER_CPU_READ_MOSTLY(unsigned int, cpumask_weight_sibling);
DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_core_map);
/* cpus sharing the last level cache: */
DECLARE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map);
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index 453cf38..dd19c71 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -111,6 +111,7 @@ extern const struct cpumask *cpu_coregroup_mask(int cpu);
#ifdef CONFIG_SMP
#define topology_core_cpumask(cpu) (per_cpu(cpu_core_map, cpu))
#define topology_sibling_cpumask(cpu) (per_cpu(cpu_sibling_map, cpu))
+#define topology_sibling_weight(cpu) (per_cpu(cpumask_weight_sibling, cpu))
extern unsigned int __max_logical_packages;
#define topology_max_packages() (__max_logical_packages)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 362dd89..20bf676 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -85,6 +85,10 @@
DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map);
EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
+/* representing number of HT siblings of each CPU */
+DEFINE_PER_CPU_READ_MOSTLY(unsigned int, cpumask_weight_sibling);
+EXPORT_PER_CPU_SYMBOL(cpumask_weight_sibling);
+
/* representing HT and core siblings of each logical CPU */
DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_core_map);
EXPORT_PER_CPU_SYMBOL(cpu_core_map);
@@ -520,6 +524,8 @@ void set_cpu_sibling_map(int cpu)
if (!has_mp) {
cpumask_set_cpu(cpu, topology_sibling_cpumask(cpu));
+ per_cpu(cpumask_weight_sibling, cpu) =
+ cpumask_weight(topology_sibling_cpumask(cpu));
cpumask_set_cpu(cpu, cpu_llc_shared_mask(cpu));
cpumask_set_cpu(cpu, topology_core_cpumask(cpu));
c->booted_cores = 1;
@@ -529,8 +535,12 @@ void set_cpu_sibling_map(int cpu)
for_each_cpu(i, cpu_sibling_setup_mask) {
o = &cpu_data(i);
- if ((i == cpu) || (has_smt && match_smt(c, o)))
+ if ((i == cpu) || (has_smt && match_smt(c, o))) {
link_mask(topology_sibling_cpumask, cpu, i);
+ threads = cpumask_weight(topology_sibling_cpumask(cpu));
+ per_cpu(cpumask_weight_sibling, cpu) = threads;
+ per_cpu(cpumask_weight_sibling, i) = threads;
+ }
if ((i == cpu) || (has_mp && match_llc(c, o)))
link_mask(cpu_llc_shared_mask, cpu, i);
@@ -1173,6 +1183,8 @@ static __init void disable_smp(void)
else
physid_set_mask_of_physid(0, &phys_cpu_present_map);
cpumask_set_cpu(0, topology_sibling_cpumask(0));
+ per_cpu(cpumask_weight_sibling, 0) =
+ cpumask_weight(topology_sibling_cpumask(0));
cpumask_set_cpu(0, topology_core_cpumask(0));
}
@@ -1482,6 +1494,8 @@ static void remove_siblinginfo(int cpu)
for_each_cpu(sibling, topology_core_cpumask(cpu)) {
cpumask_clear_cpu(cpu, topology_core_cpumask(sibling));
+ per_cpu(cpumask_weight_sibling, sibling) =
+ cpumask_weight(topology_sibling_cpumask(sibling));
/*/
* last thread sibling in this cpu core going down
*/
@@ -1495,6 +1509,7 @@ static void remove_siblinginfo(int cpu)
cpumask_clear_cpu(cpu, cpu_llc_shared_mask(sibling));
cpumask_clear(cpu_llc_shared_mask(cpu));
cpumask_clear(topology_sibling_cpumask(cpu));
+ per_cpu(cpumask_weight_sibling, cpu) = 0;
cpumask_clear(topology_core_cpumask(cpu));
c->cpu_core_id = 0;
c->booted_cores = 0;
diff --git a/include/linux/topology.h b/include/linux/topology.h
index cb0775e..a85aea1 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -190,6 +190,10 @@ static inline int cpu_to_mem(int cpu)
#ifndef topology_sibling_cpumask
#define topology_sibling_cpumask(cpu) cpumask_of(cpu)
#endif
+#ifndef topology_sibling_weight
+#define topology_sibling_weight(cpu) \
+ cpumask_weight(topology_sibling_cpumask(cpu))
+#endif
#ifndef topology_core_cpumask
#define topology_core_cpumask(cpu) cpumask_of(cpu)
#endif
--
2.9.3
