What architecture are you referring to? "High memory" and "Low memory" apply to x86_32 (see arch/x86/Kconfig), but not to x86_64, where all physical memory is directly usable by the kernel (see Documentation/x86/x86_64/mm.rst). On Thu, Nov 14, 2019 at 4:30 PM William Tambe <tambewilliam@xxxxxxxxx> wrote: > > How to tell whether an address is from low-memory or high-memory ? > > And are addresses in low-memory always a 1-to-1 mapping to physical memory ?
