On Wed, Dec 19, 2001 at 11:07:11AM +0530, Bharata B Rao wrote: > Please consider the following definitions from include/linux/irq_cpustat.h > -------------------------- > #ifdef CONFIG_SMP > #define __IRQ_STAT(cpu, member) (irq_stat[cpu].member) > #else > #define __IRQ_STAT(cpu, member) ((void)(cpu), irq_stat[0].member) > #endif I can only assume this is for performance. cpu might not be constant to the compiler, so the first would still have an indirection overhead on UP. The second one, however, lets the compiler optimise as the value of cpu is discarded (assume its evaluation has not side effects that is ;) regards john -- "...life's not a paragraph and death i think is no parenthesis" - e. e. cummings -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ IRC Channel: irc.openprojects.net / #kernelnewbies Web Page: http://www.kernelnewbies.org/
