Re: [RFC][PATCH] enable VMSPLIT for highmem kernels

Dave Hansen
2006-08-02T20:58:13Z

Well, I somehow managed to post that without appending my description.
Here goes:

The current VMSPLIT Kconfig option is disabled whenever highmem
is on. This is a bit screwy because the people who need to
change VMSPLIT the most tend to be the ones with highmem and
constrained lowmem.

So, remove the highmem dependency. But, re-include the
dependency for the "full 1GB of lowmem" option. You can't have
the full 1GB of lowmem and highmem because of the need for the
vmalloc(), kmap(), etc... areas.

I thought there would be at least a bit of tweaking to do to
get it to work, but everything seems OK.

Boot tested on a 4GB x86 machine, and a 12GB 3-node NUMA-Q:

elm3b82:~# cat /proc/meminfo
MemTotal: 3695412 kB
MemFree: 3659540 kB
...
LowTotal: 2909008 kB
LowFree: 2892324 kB
...
elm3b82:~# zgrep PAE /proc/config.gz
CONFIG_X86_PAE=y

larry:~# cat /proc/meminfo
MemTotal: 11845900 kB
MemFree: 11786748 kB
...
LowTotal: 2855180 kB
LowFree: 2830092 kB

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>

-- Dave