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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging] x86: always park offline CPUs
commit b0597289ebf89cda98d57f80014c633b9be18140
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon Sep 21 09:57:22 2026 +0200
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Sep 21 09:57:22 2026 +0200
x86: always park offline CPUs
While on AMD (or Hygon) CPUs the situation isn't as bad wrt broadcasting
of #MC, some "multicast" can still happen. Therefore the reasoning to park
CPUs rather than fully offlining them applies everywhere.
Don't retain the dependency on the "mce=" cmdline option either: That
option may best be dropped as well, as not enabling MCE will result in a
shutdown when #MC would otherwise be raised.
Drop the global variable, using a #define (just like common code does)
instead. Outside of common code, simplify expressions / code accordingly.
(In common code we still have to cater for x86 wanting it different from
everyone else.)
Suggested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
xen/arch/x86/acpi/cpu_idle.c | 4 ++--
xen/arch/x86/cpu/common.c | 3 ---
xen/arch/x86/cpu/mcheck/mce.c | 9 +--------
xen/arch/x86/genapic/x2apic.c | 6 +-----
xen/arch/x86/include/asm/percpu.h | 2 +-
xen/arch/x86/include/asm/smp.h | 6 ------
xen/arch/x86/mpparse.c | 8 ++------
xen/arch/x86/setup.c | 3 +--
xen/arch/x86/smp.c | 4 +---
xen/arch/x86/smpboot.c | 4 +---
xen/include/xen/percpu.h | 2 +-
11 files changed, 11 insertions(+), 40 deletions(-)
diff --git a/xen/arch/x86/acpi/cpu_idle.c b/xen/arch/x86/acpi/cpu_idle.c
index 1a749fabd2..56b22a2ff3 100644
--- a/xen/arch/x86/acpi/cpu_idle.c
+++ b/xen/arch/x86/acpi/cpu_idle.c
@@ -436,7 +436,7 @@ static void cf_check dump_cx(unsigned char key)
if ( cpu_online(cpu) )
print_acpi_power(cpu, power);
- else if ( park_offline_cpus )
+ else
printk("CPU%u parked in state %u (C%u)\n", cpu,
power->last_state ? power->last_state->idx : 1,
power->last_state ? power->last_state->type : 1);
@@ -1360,7 +1360,7 @@ long set_cx_pminfo(uint32_t acpi_id, struct
xen_processor_power *power)
* If we've just learned of more available C states, wake the CPU if
* it's parked, so it can go back to sleep in perhaps a deeper state.
*/
- if ( park_offline_cpus && apic_id != BAD_APICID )
+ if ( apic_id != BAD_APICID )
{
unsigned long flags;
diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index d045ed6b41..43785d19cc 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -443,9 +443,6 @@ void __init early_cpu_init(bool verbose)
* here.
*/
- if (!(c->vendor & (X86_VENDOR_AMD | X86_VENDOR_HYGON)))
- park_offline_cpus = opt_mce;
-
/*
* If nominal freq isn't available, use highest, thus causing NOW()
* output to move more slowly. See preset_tsc_scale().
diff --git a/xen/arch/x86/cpu/mcheck/mce.c b/xen/arch/x86/cpu/mcheck/mce.c
index 64fa66f026..1888f22d15 100644
--- a/xen/arch/x86/cpu/mcheck/mce.c
+++ b/xen/arch/x86/cpu/mcheck/mce.c
@@ -716,15 +716,8 @@ static int cf_check cpu_callback(
rc = cpu_bank_alloc(cpu);
break;
- case CPU_UP_CANCELED:
- case CPU_DEAD:
- if ( !park_offline_cpus )
- cpu_bank_free(cpu);
- break;
-
case CPU_REMOVE:
- if ( park_offline_cpus )
- cpu_bank_free(cpu);
+ cpu_bank_free(cpu);
break;
}
diff --git a/xen/arch/x86/genapic/x2apic.c b/xen/arch/x86/genapic/x2apic.c
index 5f2765cf14..ca88593d0f 100644
--- a/xen/arch/x86/genapic/x2apic.c
+++ b/xen/arch/x86/genapic/x2apic.c
@@ -181,12 +181,8 @@ static int cf_check update_clusterinfo(
!cond_alloc_cpumask_var(&per_cpu(scratch_mask, cpu)) )
err = -ENOMEM;
break;
- case CPU_UP_CANCELED:
- case CPU_DEAD:
+
case CPU_REMOVE:
- if ( park_offline_cpus == (action != CPU_REMOVE) ||
- system_state == SYS_STATE_suspend )
- break;
if ( per_cpu(cluster_cpus, cpu) )
{
cpumask_clear_cpu(cpu, per_cpu(cluster_cpus, cpu));
diff --git a/xen/arch/x86/include/asm/percpu.h
b/xen/arch/x86/include/asm/percpu.h
index 34f589f990..fe3df03c4c 100644
--- a/xen/arch/x86/include/asm/percpu.h
+++ b/xen/arch/x86/include/asm/percpu.h
@@ -1,7 +1,7 @@
#ifndef __X86_PERCPU_H__
#define __X86_PERCPU_H__
-#define PARK_OFFLINE_CPUS_VAR
+#define park_offline_cpus true
/*
* Force uses of per_cpu() with an invalid area to attempt to access the
diff --git a/xen/arch/x86/include/asm/smp.h b/xen/arch/x86/include/asm/smp.h
index 3f16e62696..572b39b01c 100644
--- a/xen/arch/x86/include/asm/smp.h
+++ b/xen/arch/x86/include/asm/smp.h
@@ -25,12 +25,6 @@ DECLARE_PER_CPU(cpumask_var_t, scratch_cpumask);
DECLARE_PER_CPU(cpumask_var_t, hpet_scratch_cpumask);
DECLARE_PER_CPU(cpumask_var_t, send_ipi_cpumask);
-/*
- * Do we, for platform reasons, need to actually keep CPUs online when we
- * would otherwise prefer them to be off?
- */
-extern bool park_offline_cpus;
-
void smp_send_nmi_allbutself(void);
void send_IPI_mask(const cpumask_t *mask, int vector);
diff --git a/xen/arch/x86/mpparse.c b/xen/arch/x86/mpparse.c
index 1b41aa573f..3cea519152 100644
--- a/xen/arch/x86/mpparse.c
+++ b/xen/arch/x86/mpparse.c
@@ -80,16 +80,12 @@ void __init set_nr_cpu_ids(unsigned int max_cpus)
printk(XENLOG_INFO "SMP: Allowing %u CPUs (%d hotplug CPUs)\n",
max_cpus, max_t(int, max_cpus - num_processors, 0));
- if (!park_offline_cpus)
- tot_cpus = max_cpus;
nr_cpu_ids = min(tot_cpus, NR_CPUS + 0u);
if (nr_cpu_ids < num_processors)
{
unaccounted_cpus = true;
- if (park_offline_cpus)
- printk(XENLOG_WARNING
- "SMP: Cannot bring up %u further CPUs\n",
- num_processors - nr_cpu_ids);
+ printk(XENLOG_WARNING "SMP: Cannot bring up %u further CPUs\n",
+ num_processors - nr_cpu_ids);
}
#ifndef nr_cpumask_bits
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 7d71fea6c0..a636e3205c 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -2144,8 +2144,7 @@ void asmlinkage __init noreturn __start_xen(void)
/* Set up node_to_cpumask based on cpu_to_node[]. */
numa_add_cpu(i);
- if ( (park_offline_cpus || num_online_cpus() < max_cpus) &&
- !cpu_online(i) )
+ if ( !cpu_online(i) )
{
ret = cpu_up(i);
if ( ret != 0 )
diff --git a/xen/arch/x86/smp.c b/xen/arch/x86/smp.c
index 7936294f5f..ae4e5a66d7 100644
--- a/xen/arch/x86/smp.c
+++ b/xen/arch/x86/smp.c
@@ -92,9 +92,7 @@ void send_IPI_mask(const cpumask_t *mask, int vector)
if ( system_state > SYS_STATE_smp_boot &&
!unaccounted_cpus && !disabled_cpus && !cpu_in_hotplug_context() &&
/* NB: get_cpu_maps lock requires enabled interrupts. */
- local_irq_is_enabled() && (cpus_locked = get_cpu_maps()) &&
- (park_offline_cpus ||
- cpumask_equal(&cpu_online_map, &cpu_present_map)) )
+ local_irq_is_enabled() && (cpus_locked = get_cpu_maps()) )
cpumask_or(scratch, mask, cpumask_of(smp_processor_id()));
else
{
diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index cede2b886f..fb73989232 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -67,8 +67,6 @@ DEFINE_PER_CPU_READ_MOSTLY(struct stubs, stubs);
cpumask_t cpu_online_map __read_mostly;
EXPORT_SYMBOL(cpu_online_map);
-bool __read_mostly park_offline_cpus;
-
unsigned int __read_mostly nr_sockets;
cpumask_t **__read_mostly socket_cpumask;
static cpumask_t *secondary_socket_cpumask;
@@ -1151,7 +1149,7 @@ static int cf_check cpu_smpboot_callback(
break;
case CPU_UP_CANCELED:
case CPU_DEAD:
- cpu_smpboot_free(cpu, !park_offline_cpus);
+ cpu_smpboot_free(cpu, false);
break;
case CPU_REMOVE:
cpu_smpboot_free(cpu, true);
diff --git a/xen/include/xen/percpu.h b/xen/include/xen/percpu.h
index d324671b5b..88f332caab 100644
--- a/xen/include/xen/percpu.h
+++ b/xen/include/xen/percpu.h
@@ -36,7 +36,7 @@
#include <xen/types.h>
#include <asm/current.h>
-#ifndef PARK_OFFLINE_CPUS_VAR
+#if !defined(PARK_OFFLINE_CPUS_VAR) && !defined(park_offline_cpus)
/*
* Do we, for platform reasons, need to actually keep CPUs online when we
* would otherwise prefer them to be off?
--
generated by git-patchbot for /home/xen/git/xen.git#staging
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