Hello All,
I have found a set of instructions for compiling a kernel which
allows processes to access about an extra 500M of memory. I need
this functionality since I run large processes which sometimes die
because they can not allocate more then 3G of memory.
Before I go too far down this road, I want to bounce these
instructions off this list to make sure this is the best way to
get what I am after and also to see what the downsides are.
What I am susposed to do is very simple:
1) Modify page.h such that __PAGE_OFFSET is changed from 0xC0000000 to
0xE0000000.
2) Modify processor.h such that TASK_UNMAPPED_BASE is changed from
(TASK_SIZE/3) to (TASK_SIZE/16)
3) Modify vmlinux.lds similar to step 1
Then the kernel is built with CONFIG_HIGHMEM4G=y (the machines have 4G of
ram).
The part that has me concerned is that I am not sure why I need to change
__PAGE_OFFSET if CONFIG_HIGHMEM4G is on. I am not sure how these options
interact with each other. Also, what am I loosing by making __PAGE_OFFSET
this large? I believe that TASK_UNMAPPED_BASE is just moving the stack
around so that it does not get in the way of malloc(). Is this correct?
Thanks,
Jim