x86: enable MAXSMP Set MAXSMP to enable CONFIG_CPUMASK_OFFSTACK which moves cpumask's off the stack (and in structs) when using cpumask_var_t. Signed-off-by: Mike Travis Signed-off-by: Rusty Russell --- arch/x86/Kconfig | 3 ++- init/Kconfig | 7 +++++++ 2 files changed, 9 insertions(+), 1 deletion(-) diff -r f3ea59c04f68 arch/x86/Kconfig --- a/arch/x86/Kconfig Wed Oct 22 10:12:18 2008 +1100 +++ b/arch/x86/Kconfig Wed Oct 22 10:25:15 2008 +1100 @@ -572,7 +572,8 @@ config IOMMU_HELPER config MAXSMP bool "Configure Maximum number of SMP Processors and NUMA Nodes" - depends on X86_64 && SMP && BROKEN + depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL + select CPUMASK_OFFSTACK default n help Configure maximum number of CPUS and NUMA Nodes for this architecture. diff -r f3ea59c04f68 init/Kconfig --- a/init/Kconfig Wed Oct 22 10:12:18 2008 +1100 +++ b/init/Kconfig Wed Oct 22 10:25:15 2008 +1100 @@ -924,3 +924,10 @@ config CLASSIC_RCU designed for best read-side performance on non-realtime systems. Classic RCU is the default. Note that the PREEMPT_RCU symbol is used to select/deselect this option. + +config CPUMASK_OFFSTACK + bool "Force CPU masks off stack" if DEBUG_PER_CPU_MAPS + help + Use dynamic allocation for cpumask_var_t, instead of putting + them on the stack. This is a bit more expensive, but avoids + stack overflow.