On Thu, Apr 19, 2001 at 05:41:27PM -0700, Basham, Richard R wrote:
> Hello all,
>
> I am trying to use mbuff to allocate several named shared memory buffers from a
>kernel module. I have 1 G of memory but I can't seem to allocate more than somewhere
>just below 64 M of named shared memory from a kernel module. If I use malloc from
>user space I can allocate nearly all of the 1 G. It appears that this has something
>to do with a kernel limit. Has anyone come across this? Have you found a way around
>the limit?
>
Hmmm... I thought the minimum reserved for vmalloc was 128 MB.
The Linux kernel uses addresses above 0xc0000000 for it's own use.
Into this area, it needs to map PCI space, the kernel code and data,
vmalloc()'d memory, etc. Some kernels also have a 1-1 mapping of
RAM in this area. Naturally, since the area above 0xc0000000 is
1 GB large, and you have 1 GB of RAM, there's not going to much
space for anything else. If you enable CONFIG_HIGHMEM, it will
only map physical RAM that it needs, and more of the address range
is available for vmalloc, but unfortunately, this option is not
available on 2.2.
dave...
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