On Tue, Aug 16, 2005 at 12:27:12 +0200, Erik Mouw wrote: > On Tue, Aug 16, 2005 at 03:32:23PM +0530, pavan wrote: > > While i was reading manual for gsx server i found following: > > > > Recompile the kernel as a 2GB kernel by enabling the CONFIG_2GB option and > > either pass the boot-time switch mem=1983M at the LILO prompt or add it to > > lilo.conf > > > > what does this mean by 2GB kernel? > > It means that particular kernel supports 2GB of RAM. You can plug in > more RAM, but the kernel will not use it. No. The kernel supports more memory (when CONFIG_HIGHMEM is on). But it only has 2GB address space, so access to more memory suffers performance penalty, as the virtual address mapping has to be modified. > > i have 2.4.29 kernel for mandrake?does it not support 2GB RAM?do i need > > to make extra settings for kernel. > > All distros I know have a package with a "4GB", "bigmem", or "hugemen" > kernel. It's just that those kernels are inefficient on hardware > without such amount of memory. I would actually expect the "4GB" kernel to be slower with any amount of memory, since remapping and flushing part of virtual address space is at most as slow as changing and flushing the whole map and the number of maps/unmaps is likely to end up less than the number of context switches. As I understood, the "4GB" kernel is more of an answer to "Oh, but Linux eats up 1GB of our precisous address space" cries. AFAIK it is mainly shipped by distros focused on corporate customers. ------------------------------------------------------------------------------- Jan 'Bulb' Hudec <bulb@xxxxxx>
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