From a92de8c5d343c55dac581a23a8493616e68b4ec7 Mon Sep 17 00:00:00 2001 From: Ananth N Mavinakayanahalli Date: Mon, 11 Jan 2010 15:51:04 -0800 Subject: [PATCH] Revert "x86, apic: Use logical flat on intel with <= 8 logical cpus" Revert commit 4dad7c386da9008960eee5a7ef6012134f30f5b6, as this commit breaks an IBM platform with quad-core Xeon cpu's. According to Suresh, this might be an IBM platform issue, as on other Intel platforms with <= 8 logical cpu's, logical flat mode works fine irespective of physical apic id values (inline with the xapic architecture). Revert this for now because of the IBM platform breakage. Another version will be re-submitted after the complete analysis. Signed-off-by: Ananth N Mavinakayanahalli Acked-by: Suresh Siddha Signed-off-by: Linus Torvalds --- arch/x86/kernel/apic/apic.c | 26 ++++++++++++++++++-------- arch/x86/kernel/apic/probe_64.c | 15 ++++----------- 2 files changed, 22 insertions(+), 19 deletions(-) diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index aa57c079c98f6..e80f291472a41 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 + */ + 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 diff --git a/arch/x86/kernel/apic/probe_64.c b/arch/x86/kernel/apic/probe_64.c index c4cbd3080c1c3..65edc180fc829 100644 --- a/arch/x86/kernel/apic/probe_64.c +++ b/arch/x86/kernel/apic/probe_64.c @@ -64,23 +64,16 @@ void __init default_setup_apic_routing(void) apic = &apic_x2apic_phys; else apic = &apic_x2apic_cluster; + printk(KERN_INFO "Setting APIC routing to %s\n", apic->name); } #endif if (apic == &apic_flat) { - switch (boot_cpu_data.x86_vendor) { - case X86_VENDOR_INTEL: - if (num_processors > 8) - apic = &apic_physflat; - break; - case X86_VENDOR_AMD: - if (max_physical_apicid >= 8) - apic = &apic_physflat; - } + if (max_physical_apicid >= 8) + apic = &apic_physflat; + printk(KERN_INFO "Setting APIC routing to %s\n", apic->name); } - printk(KERN_INFO "Setting APIC routing to %s\n", apic->name); - if (is_vsmp_box()) { /* need to update phys_pkg_id */ apic->phys_pkg_id = apicid_phys_pkg_id; -- 2.39.5