A quick question on VM

["sahlot arvind" <asahlot@xxxxxxxxx>]

Hi All,

 

I just started learning Linux Virtual Memory Management Subsystem.

I see the memory is divided into three zones. Comments in file mm/mmzone.h

 

/*

 * ZONE_DMA       < 16 MB       ISA DMA capable memory
 * ZONE_NORMAL  16-896 MB       direct mapped by the kernel
 * ZONE_HIGHMEM  > 896 MB       only page cache and user processes
 */
 

Here second comment (ZONE_NORMAL) says that it is directly mapped by kernel.

Could anybody please tell me what does direct mean here?

Does this mean Physical address = Virtual Address???

 

 

Thanks

 - Arvind