From: Thomas Gleixner <[email protected]>
There is no point in assigning the CPU numbers during ACPI physical
hotplug. The number of possible hotplug CPUs is known when the possible map
is initialized, so the CPU numbers can be associated to the registered
non-present APIC IDs right there.
This allows to put more code into the __init section and makes the related
data __ro_after_init.
Signed-off-by: Thomas Gleixner <[email protected]>
---
arch/x86/kernel/cpu/topology.c | 29 ++++++++++++++++++-----------
1 file changed, 18 insertions(+), 11 deletions(-)
---
--- a/arch/x86/kernel/cpu/topology.c
+++ b/arch/x86/kernel/cpu/topology.c
@@ -45,7 +45,7 @@ EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_a
DECLARE_BITMAP(phys_cpu_present_map, MAX_LOCAL_APIC) __read_mostly;
/* Used for CPU number allocation and parallel CPU bringup */
-u32 cpuid_to_apicid[] __read_mostly = { [0 ... NR_CPUS - 1] = BAD_APICID, };
+u32 cpuid_to_apicid[] __ro_after_init = { [0 ... NR_CPUS - 1] = BAD_APICID, };
/* Bitmaps to mark registered APICs at each topology domain */
static struct { DECLARE_BITMAP(map, MAX_LOCAL_APIC); } apic_maps[TOPO_MAX_DOMAIN] __ro_after_init;
@@ -60,7 +60,7 @@ static struct {
unsigned int nr_rejected_cpus;
u32 boot_cpu_apic_id;
u32 real_bsp_apic_id;
-} topo_info __read_mostly = {
+} topo_info __ro_after_init = {
.nr_assigned_cpus = 1,
.boot_cpu_apic_id = BAD_APICID,
.real_bsp_apic_id = BAD_APICID,
@@ -133,7 +133,7 @@ static int topo_lookup_cpuid(u32 apic_id
return -ENODEV;
}
-static int topo_get_cpunr(u32 apic_id)
+static __init int topo_get_cpunr(u32 apic_id)
{
int cpu = topo_lookup_cpuid(apic_id);
@@ -149,8 +149,6 @@ static void topo_set_cpuids(unsigned int
early_per_cpu(x86_cpu_to_apicid, cpu) = apic_id;
early_per_cpu(x86_cpu_to_acpiid, cpu) = acpi_id;
#endif
- cpuid_to_apicid[cpu] = apic_id;
-
set_cpu_possible(cpu, true);
set_cpu_present(cpu, true);
@@ -206,6 +204,8 @@ static __init void topo_register_apic(u3
cpu = 0;
else
cpu = topo_get_cpunr(apic_id);
+
+ cpuid_to_apicid[cpu] = apic_id;
topo_set_cpuids(cpu, apic_id, acpi_id);
} else {
topo_info.nr_disabled_cpus++;
@@ -277,12 +277,9 @@ int topology_hotplug_apic(u32 apic_id, u
return -ENODEV;
cpu = topo_lookup_cpuid(apic_id);
- if (cpu < 0) {
- if (topo_info.nr_assigned_cpus >= nr_cpu_ids)
- return -ENOSPC;
+ if (cpu < 0)
+ return -ENOSPC;
- cpu = topo_assign_cpunr(apic_id);
- }
set_bit(apic_id, phys_cpu_present_map);
topo_set_cpuids(cpu, apic_id, acpi_id);
return cpu;
@@ -353,6 +350,7 @@ void __init topology_init_possible_cpus(
unsigned int disabled = topo_info.nr_disabled_cpus;
unsigned int total = assigned + disabled;
unsigned int cpu, allowed = 1;
+ u32 apicid;
if (!restrict_to_up()) {
if (WARN_ON_ONCE(assigned > nr_cpu_ids)) {
@@ -381,8 +379,17 @@ void __init topology_init_possible_cpus(
init_cpu_present(cpumask_of(0));
init_cpu_possible(cpumask_of(0));
+ /* Assign CPU numbers to non-present CPUs */
+ for (apicid = 0; disabled; disabled--, apicid++) {
+ apicid = find_next_andnot_bit(apic_maps[TOPO_SMT_DOMAIN].map, phys_cpu_present_map,
+ MAX_LOCAL_APIC, apicid);
+ if (apicid >= MAX_LOCAL_APIC)
+ break;
+ cpuid_to_apicid[topo_info.nr_assigned_cpus++] = apicid;
+ }
+
for (cpu = 0; cpu < allowed; cpu++) {
- u32 apicid = cpuid_to_apicid[cpu];
+ apicid = cpuid_to_apicid[cpu];
set_cpu_possible(cpu, true);
The following commit has been merged into the x86/apic branch of tip:
Commit-ID: ea2dd8a5d4361ef0b000196043fa407f05b16f1d
Gitweb: https://git.kernel.org/tip/ea2dd8a5d4361ef0b000196043fa407f05b16f1d
Author: Thomas Gleixner <[email protected]>
AuthorDate: Tue, 13 Feb 2024 22:05:59 +01:00
Committer: Thomas Gleixner <[email protected]>
CommitterDate: Thu, 15 Feb 2024 22:07:44 +01:00
x86/cpu/topology: Assign hotpluggable CPUIDs during init
There is no point in assigning the CPU numbers during ACPI physical
hotplug. The number of possible hotplug CPUs is known when the possible map
is initialized, so the CPU numbers can be associated to the registered
non-present APIC IDs right there.
This allows to put more code into the __init section and makes the related
data __ro_after_init.
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Michael Kelley <[email protected]>
Tested-by: Sohil Mehta <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/kernel/cpu/topology.c | 29 ++++++++++++++++++-----------
1 file changed, 18 insertions(+), 11 deletions(-)
diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c
index a6d045b..07124da 100644
--- a/arch/x86/kernel/cpu/topology.c
+++ b/arch/x86/kernel/cpu/topology.c
@@ -45,7 +45,7 @@ EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_acpiid);
DECLARE_BITMAP(phys_cpu_present_map, MAX_LOCAL_APIC) __read_mostly;
/* Used for CPU number allocation and parallel CPU bringup */
-u32 cpuid_to_apicid[] __read_mostly = { [0 ... NR_CPUS - 1] = BAD_APICID, };
+u32 cpuid_to_apicid[] __ro_after_init = { [0 ... NR_CPUS - 1] = BAD_APICID, };
/* Bitmaps to mark registered APICs at each topology domain */
static struct { DECLARE_BITMAP(map, MAX_LOCAL_APIC); } apic_maps[TOPO_MAX_DOMAIN] __ro_after_init;
@@ -60,7 +60,7 @@ static struct {
unsigned int nr_rejected_cpus;
u32 boot_cpu_apic_id;
u32 real_bsp_apic_id;
-} topo_info __read_mostly = {
+} topo_info __ro_after_init = {
.nr_assigned_cpus = 1,
.boot_cpu_apic_id = BAD_APICID,
.real_bsp_apic_id = BAD_APICID,
@@ -133,7 +133,7 @@ static int topo_lookup_cpuid(u32 apic_id)
return -ENODEV;
}
-static int topo_get_cpunr(u32 apic_id)
+static __init int topo_get_cpunr(u32 apic_id)
{
int cpu = topo_lookup_cpuid(apic_id);
@@ -149,8 +149,6 @@ static void topo_set_cpuids(unsigned int cpu, u32 apic_id, u32 acpi_id)
early_per_cpu(x86_cpu_to_apicid, cpu) = apic_id;
early_per_cpu(x86_cpu_to_acpiid, cpu) = acpi_id;
#endif
- cpuid_to_apicid[cpu] = apic_id;
-
set_cpu_possible(cpu, true);
set_cpu_present(cpu, true);
@@ -206,6 +204,8 @@ static __init void topo_register_apic(u32 apic_id, u32 acpi_id, bool present)
cpu = 0;
else
cpu = topo_get_cpunr(apic_id);
+
+ cpuid_to_apicid[cpu] = apic_id;
topo_set_cpuids(cpu, apic_id, acpi_id);
} else {
topo_info.nr_disabled_cpus++;
@@ -277,12 +277,9 @@ int topology_hotplug_apic(u32 apic_id, u32 acpi_id)
return -ENODEV;
cpu = topo_lookup_cpuid(apic_id);
- if (cpu < 0) {
- if (topo_info.nr_assigned_cpus >= nr_cpu_ids)
- return -ENOSPC;
+ if (cpu < 0)
+ return -ENOSPC;
- cpu = topo_assign_cpunr(apic_id);
- }
set_bit(apic_id, phys_cpu_present_map);
topo_set_cpuids(cpu, apic_id, acpi_id);
return cpu;
@@ -353,6 +350,7 @@ void __init topology_init_possible_cpus(void)
unsigned int disabled = topo_info.nr_disabled_cpus;
unsigned int total = assigned + disabled;
unsigned int cpu, allowed = 1;
+ u32 apicid;
if (!restrict_to_up()) {
if (WARN_ON_ONCE(assigned > nr_cpu_ids)) {
@@ -381,8 +379,17 @@ void __init topology_init_possible_cpus(void)
init_cpu_present(cpumask_of(0));
init_cpu_possible(cpumask_of(0));
+ /* Assign CPU numbers to non-present CPUs */
+ for (apicid = 0; disabled; disabled--, apicid++) {
+ apicid = find_next_andnot_bit(apic_maps[TOPO_SMT_DOMAIN].map, phys_cpu_present_map,
+ MAX_LOCAL_APIC, apicid);
+ if (apicid >= MAX_LOCAL_APIC)
+ break;
+ cpuid_to_apicid[topo_info.nr_assigned_cpus++] = apicid;
+ }
+
for (cpu = 0; cpu < allowed; cpu++) {
- u32 apicid = cpuid_to_apicid[cpu];
+ apicid = cpuid_to_apicid[cpu];
set_cpu_possible(cpu, true);