linux.conf.au
Optimization

 	if (length > 0) {
 		u32 *dst = (u32*)buffer;
 		u32 *src = (u32*)(((u8*)ip_rt_acct) + offset);
 
 		memcpy(dst, src, length);
 
 #ifdef CONFIG_SMP
 		if (smp_num_cpus > 1 || cpu_logical_map(0) != 0) {
 			int i;
 			int cnt = length / 4;
 
 			for (i = 0; i < smp_num_cpus; i++) {
 				int cpu = cpu_logical_map(i);
 				int k;
 
 				if (cpu == 0)
 					continue;
 
 				src = (u32*)(((u8*)ip_rt_acct) + offset +
 					cpu * 256 * sizeof(struct ip_rt_acct));
 
 				for (k = 0; k < cnt; k++)
 					dst[k] += src[k];
 			}
 		}
 #endif
 		return length;
 	}
 	return 0;