In article <5pgv9o$rq5$1@nova.noris.de> you write:
>[...]
>The memory map is rather simple: Below PAGE_OFFSET => virtual address space
>of user process. Above PAGE_OFFSET => real memory. The kernel also needs
>some space above its real memory space for vmalloc(), I/O remapping, and
>possibly some others I've conveniently forgotten. ;-)
Does that mean, if you have a 1GB real mem machine, there's 1GB of virtual
memory already used for a permanent mapping of the real 1GB of memory?
Till now I thought, Linux uses a similar memory map as most BSD's:
0 PGSIZE VM_MAXUSER_ADDRESS ... VM_MIN_KERNEL_ADDRESS ...
invalid user program user stack|user pages kernel space
And if the kernel needs physical memory access, it sets it up in some
kernel space as the need arises.
Do you really need all real memory mapped 1:1 in kernel space?
>[...]
Regards, Felix.