Messages in this thread Patch in this message | | | From | "Fenghua Yu" <> | Subject | [PATCH v3 1/7] x86/topology.c: Support functions for BSP online/offline | Date | Wed, 9 Nov 2011 16:34:11 -0800 |
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From: Fenghua Yu <fenghua.yu@intel.com>
By default, BSP can't be hotpluggable because bsp_hotpluggable is 0. Kernel parameter bsp_hotplug can enable BSP hotplug feature.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> --- arch/x86/kernel/topology.c | 24 +++++++++++++++++------- 1 files changed, 17 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/topology.c b/arch/x86/kernel/topology.c index 76ee977..a3fc939 100644 --- a/arch/x86/kernel/topology.c +++ b/arch/x86/kernel/topology.c @@ -35,18 +35,28 @@ static DEFINE_PER_CPU(struct x86_cpu, cpu_devices); #ifdef CONFIG_HOTPLUG_CPU + +static int bsp_hotpluggable; + +static int __init enable_bsp_hotplug(char *str) +{ + bsp_hotpluggable = 1; + return 1; +} + +__setup("bsp_hotplug", enable_bsp_hotplug); + int __ref arch_register_cpu(int num) { /* - * CPU0 cannot be offlined due to several - * restrictions and assumptions in kernel. This basically - * doesn't add a control file, one cannot attempt to offline - * BSP. + * Resume from suspend/hibernate depends on BSP. PIC interrupts depend + * on BSP. * - * Also certain PCI quirks require not to enable hotplug control - * for all CPU's. + * If the BSP depencies are under control, one can tell kernel to + * enable BSP hotplug. This basically adds a control file and + * one can attempt to offline BSP. */ - if (num) + if (num || bsp_hotpluggable) per_cpu(cpu_devices, num).cpu.hotpluggable = 1; return register_cpu(&per_cpu(cpu_devices, num).cpu, num); -- 1.6.0.3
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