On 04/03/2013 06:11 PM, Simon Jeons wrote: > > Why we consider boot_cpu_data.x86_phys_bits instead of e820 map here? > Because x86_phys_bits is what controls how much address space the processor has. e820 tells us how much *RAM* the machine has, or specifically, how much RAM the machine had on boot. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>