From 066000dd856709b6980123eb39b957fe26993f7b 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 2fbd07a5f5d1295fa9b0c0564ec27da7c276a75a, 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 aa57c07..e80f291 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 c4cbd30..65edc18 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; -- 1.8.2.3