Zum Thema "per process user space", siehe auch Red Hat Enterprise Linux WS 3 Release Notes
Red Hat Enterprise Linux 3 includes a new kernel known as the hugemem kernel. This kernel supports a 4GB per process user space (versus 3GB for the other kernels), and a 4GB direct kernel space. Using this kernel allows Red Hat Enterprise Linux to run on systems with up to 64GB of main memory. The hugemem kernel is required in order to use all the memory in system configurations containing more than 16GB of memory. The hugemem kernel can also benefit configurations running with less memory (if running an application that could benefit from the larger per process user space, for example.)
Ein Kerl, dessen Vorname mit L anfängt hat dazu übrigens folgende Meinung ( LKML: Linus Torvalds: Re: mmap dirty limits on 32 bit kernels (Was: [bUG] New Kernel Bugs) )
Yeah. I always considered HIGHMEM to just be unusable.
HIGHMEM was a mistake in the first place.