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Diffstat (limited to 'arch/x86/kernel/apic/apic.c')
-rw-r--r--arch/x86/kernel/apic/apic.c26
1 files changed, 18 insertions, 8 deletions
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index aa57c079c98f..e80f291472a4 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -62,7 +62,7 @@ unsigned int boot_cpu_physical_apicid = -1U;
/*
* The highest APIC ID seen during enumeration.
*
- * On AMD, this determines the messaging protocol we can use: if all APIC IDs
+ * This determines the messaging protocol we can use: if all APIC IDs
* are in the 0 ... 7 range, then we can use logical addressing which
* has some performance advantages (better broadcasting).
*
@@ -1898,14 +1898,24 @@ void __cpuinit generic_processor_info(int apicid, int version)
max_physical_apicid = apicid;
#ifdef CONFIG_X86_32
- switch (boot_cpu_data.x86_vendor) {
- case X86_VENDOR_INTEL:
- if (num_processors > 8)
- def_to_bigsmp = 1;
- break;
- case X86_VENDOR_AMD:
- if (max_physical_apicid >= 8)
+ /*
+ * Would be preferable to switch to bigsmp when CONFIG_HOTPLUG_CPU=y
+ * but we need to work other dependencies like SMP_SUSPEND etc
+ * before this can be done without some confusion.
+ * if (CPU_HOTPLUG_ENABLED || num_processors > 8)
+ * - Ashok Raj <ashok.raj@intel.com>
+ */
+ if (max_physical_apicid >= 8) {
+ switch (boot_cpu_data.x86_vendor) {
+ case X86_VENDOR_INTEL:
+ if (!APIC_XAPIC(version)) {
+ def_to_bigsmp = 0;
+ break;
+ }
+ /* If P4 and above fall through */
+ case X86_VENDOR_AMD:
def_to_bigsmp = 1;
+ }
}
#endif