On Thu, 2004-11-04 at 09:20 +0800, Bao zhao wrote: > In kernel, NR_CPU is macro and represents the number of CPUs. Many arrays > use it to define array's size . But the number of CPUs can be known only > when smp machine boot, so when compling the kernel , NR_CPU has no value. > I am cofused by it . NR_CPUS represents the maximum number of processors supported, not the current number on a live system (that is smp_nr_cpus or something similar). The value is known at compile-time. It is set by CONFIG_NR_CPUS which is usually 32 if CONFIG_SMP is set. The macro is just used to size static arrays, although such use is falling out of favor as we now have support for many processors. Robert Love -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
