NR_CPUS
typedef unsigned long mm_context_t[NR_CPUS];
typedef unsigned long mm_context_id_t[NR_CPUS];
#define NR_CPUS CONFIG_NR_CPUS
#define NR_CPUS 1
#define NR_CPUS CONFIG_NR_CPUS
#define NR_CPUS 1024
#define NR_CPUS (sizeof(struct cpumask) * 8)
#define NR_CPUS 256