🚀 go-pugleaf

Gary Menna <gary.menna@cmc.cwo.net.au> wrote:

> I am running Redhat 7.3 on a Compaq with 1 GB RAM    2.4.18-10smp
> I get the following message :
> Use a HIGHMEM enabled kernel.
> 896MB LOWMEM available
> 
> I thought highmem enabled kernel was only required for =>4GB  RAM
> Can anyone enlighten me on this .

from Documentation/Configure.help (in the kernel source tree) :

CONFIG_NOHIGHMEM
  Linux can use up to 64 Gigabytes of physical memory on x86 systems.
[......]

  If you are compiling a kernel which will never run on a machine with
  more than 960 megabytes of total physical RAM, answer "off" here (default
  choice and suitable for most users). This will result in a "3GB/1GB"
  split: 3GB are mapped so that each process sees a 3GB virtual memory
  space and the remaining part of the 4GB virtual memory space is used
  by the kernel to permanently map as much physical memory as
  possible.

  If the machine has between 1 and 4 Gigabytes physical RAM, then
  answer "4GB" here.
[......]

your kernel has probably been compiled using the default of "off" - which 
means 960MB is available - which would probably work out right with the
"896MB LOWMEM available" message (the rest of the 960MB is being used for 
kernel code, buffers, stack, etc...)

is it worth recompiling the kernel for that last 40MB? ;-)

will

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