From 066000dd856709b6980123eb39b957fe26993f7b Mon Sep 17 00:00:00 2001 From: Ananth N Mavinakayanahalli Date: Mon, 11 Jan 2010 15:51:04 -0800 Subject: 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/probe_64.c | 15 ++++----------- 1 file changed, 4 insertions(+), 11 deletions(-) (limited to 'arch/x86/kernel/apic/probe_64.c') diff --git a/arch/x86/kernel/apic/probe_64.c b/arch/x86/kernel/apic/probe_64.c index c4cbd3080c1c..65edc180fc82 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; -- cgit v1.2.2 From bb668da6d6f2bec8a63838c098d9515eccb22cc4 Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Mon, 18 Jan 2010 12:10:49 -0800 Subject: x86, apic: use logical flat for systems with <= 8 logical cpus We can use logical flat mode if there are <= 8 logical cpu's (irrespective of physical apic id values). This will enable simplified and efficient IPI and device interrupt routing on such platforms. This has been tested to work on both Intel and AMD platforms. Exceptions like IBM summit platform which can't use logical flat mode are addressed by using OEM platform checks. Signed-off-by: Suresh Siddha Signed-off-by: Yinghai Lu Cc: Ananth N Mavinakayanahalli Cc: Chris McDermott Signed-off-by: Linus Torvalds --- arch/x86/kernel/apic/probe_64.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) (limited to 'arch/x86/kernel/apic/probe_64.c') diff --git a/arch/x86/kernel/apic/probe_64.c b/arch/x86/kernel/apic/probe_64.c index 65edc180fc82..450fe2064a14 100644 --- a/arch/x86/kernel/apic/probe_64.c +++ b/arch/x86/kernel/apic/probe_64.c @@ -64,15 +64,13 @@ 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) { - if (max_physical_apicid >= 8) + if (apic == &apic_flat && num_processors > 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 */ -- cgit v1.2.2 From 681ee44d40d7c93b42118320e4620d07d8704fd6 Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Tue, 9 Feb 2010 18:01:44 -0800 Subject: x86, apic: Don't use logical-flat mode when CPU hotplug may exceed 8 CPUs We need to fall back from logical-flat APIC mode to physical-flat mode when we have more than 8 CPUs. However, in the presence of CPU hotplug(with bios listing not enabled but possible cpus as disabled cpus in MADT), we have to consider the number of possible CPUs rather than the number of current CPUs; otherwise we may cross the 8-CPU boundary when CPUs are added later. 32bit apic code can use more cleanups (like the removal of vendor checks in 32bit default_setup_apic_routing()) and more unifications with 64bit code. Yinghai has some patches in works already. This patch addresses the boot issue that is reported in the virtualization guest context. [ hpa: incorporated function annotation feedback from Yinghai Lu ] Signed-off-by: Suresh Siddha LKML-Reference: <1265767304.2833.19.camel@sbs-t61.sc.intel.com> Acked-by: Shaohui Zheng Reviewed-by: Yinghai Lu Cc: Signed-off-by: H. Peter Anvin --- arch/x86/kernel/apic/probe_64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kernel/apic/probe_64.c') diff --git a/arch/x86/kernel/apic/probe_64.c b/arch/x86/kernel/apic/probe_64.c index 450fe2064a14..83e9be4778e2 100644 --- a/arch/x86/kernel/apic/probe_64.c +++ b/arch/x86/kernel/apic/probe_64.c @@ -67,7 +67,7 @@ void __init default_setup_apic_routing(void) } #endif - if (apic == &apic_flat && num_processors > 8) + if (apic == &apic_flat && num_possible_cpus() > 8) apic = &apic_physflat; printk(KERN_INFO "Setting APIC routing to %s\n", apic->name); -- cgit v1.2.2