[RFC][PATCH] enable VMSPLIT for highmem kernels

[RFC][PATCH] enable VMSPLIT for highmem kernels

[Dave Hansen]

---

 lxc-dave/arch/i386/Kconfig |    3 ++-
 1 files changed, 2 insertions(+), 1 deletion(-)

diff -puN arch/i386/Kconfig~split-for-pae arch/i386/Kconfig
--- lxc/arch/i386/Kconfig~split-for-pae	2006-08-02 12:58:55.000000000 -0700
+++ lxc-dave/arch/i386/Kconfig	2006-08-02 13:02:55.000000000 -0700
@@ -497,7 +497,7 @@ config HIGHMEM64G
 endchoice
 
 choice
-	depends on EXPERIMENTAL && !X86_PAE
+	depends on EXPERIMENTAL
 	prompt "Memory split" if EMBEDDED
 	default VMSPLIT_3G
 	help
@@ -519,6 +519,7 @@ choice
 	config VMSPLIT_3G
 		bool "3G/1G user/kernel split"
 	config VMSPLIT_3G_OPT
+		depends on !HIGHMEM
 		bool "3G/1G user/kernel split (for full 1G low memory)"
 	config VMSPLIT_2G
 		bool "2G/2G user/kernel split"
_

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

[Dave Hansen]

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