Messages in this thread Patch in this message | | | Date | Tue, 9 Feb 2010 18:00:39 GMT | From | tip-bot for Suresh Siddha <> | Subject | [tip:x86/urgent] x86, apic: Don't use logical-flat mode when CPU hotplug may exceed 8 CPUs |
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Commit-ID: 418f727639cfc8f03068aae09f473c493c759b9b Gitweb: http://git.kernel.org/tip/418f727639cfc8f03068aae09f473c493c759b9b Author: Suresh Siddha <suresh.b.siddha@intel.com> AuthorDate: Tue, 9 Feb 2010 09:18:35 -0800 Committer: H. Peter Anvin <hpa@zytor.com> CommitDate: Tue, 9 Feb 2010 09:29:17 -0800
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, 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.
Reported-by: Shaohui Zheng <shaohui.zheng@intel.com> Acked-by: Shaohui Zheng <shaohui.zheng@intel.com> Cc: Yinghai Lu <yinghai@kernel.org> LKML-Reference: <20100118201256.672679042@sbs-t61.sc.intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: <stable@kernel.org> --- arch/x86/kernel/apic/apic.c | 2 +- arch/x86/kernel/apic/probe_64.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 3987e44..fc1d579 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1892,7 +1892,7 @@ void __cpuinit generic_processor_info(int apicid, int version) max_physical_apicid = apicid; #ifdef CONFIG_X86_32 - if (num_processors > 8) { + if (num_possible_cpus() > 8) { switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_INTEL: if (!APIC_XAPIC(version)) { diff --git a/arch/x86/kernel/apic/probe_64.c b/arch/x86/kernel/apic/probe_64.c index 450fe20..83e9be4 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);
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