diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index 2f6622cead1fbbcf527e2685de7a43f325b9796e..1b442fb2001f4b9e7746ff13b35d017e43ac28be 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -35,16 +35,20 @@ typedef struct cpumask { DECLARE_BITMAP(bits, NR_CPUS); } cpumask_t; */ #define cpumask_pr_args(maskp) nr_cpu_ids, cpumask_bits(maskp) -#if NR_CPUS == 1 -#define nr_cpu_ids 1U +#if (NR_CPUS == 1) || defined(CONFIG_FORCE_NR_CPUS) +#define nr_cpu_ids ((unsigned int)NR_CPUS) #else extern unsigned int nr_cpu_ids; +#endif static inline void set_nr_cpu_ids(unsigned int nr) { +#if (NR_CPUS == 1) || defined(CONFIG_FORCE_NR_CPUS) + WARN_ON(nr != nr_cpu_ids); +#else nr_cpu_ids = nr; -} #endif +} /* Deprecated. Always use nr_cpu_ids. */ #define nr_cpumask_bits nr_cpu_ids diff --git a/kernel/smp.c b/kernel/smp.c index 150310a0947a63386d14a937bd6ae6069fdc962f..661d09ae5d6aa2eaeb9e318b69a6fe038ec92f75 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -1088,7 +1088,7 @@ static int __init maxcpus(char *str) early_param("maxcpus", maxcpus); -#if (NR_CPUS > 1) +#if (NR_CPUS > 1) && !defined(CONFIG_FORCE_NR_CPUS) /* Setup number of possible processor ids */ unsigned int nr_cpu_ids __read_mostly = NR_CPUS; EXPORT_SYMBOL(nr_cpu_ids); diff --git a/lib/Kconfig b/lib/Kconfig index dc1ab2ed1dc6e7d19b9aa492081da04d6a40fee2..77ead982c8b9d31b25a8c7c343137bde96c1f280 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -527,6 +527,15 @@ config CPUMASK_OFFSTACK them on the stack. This is a bit more expensive, but avoids stack overflow. +config FORCE_NR_CPUS + bool "NR_CPUS is set to an actual number of CPUs" + depends on SMP + help + Say Yes if you have NR_CPUS set to an actual number of possible + CPUs in your system, not to a default value. This forces the core + code to rely on compile-time value and optimize kernel routines + better. + config CPU_RMAP bool depends on SMP