HIGHMEM64G Kernel (2.6.23.1) makes system crawl

["Rajkumar S" <rajkumars@gmail.com>]

Hello,

I am using a Core 2 Duo E6750 CPU on an intel DG33FB mother board with
4GB Ram, running Debian Lenny.

Since the box has 4 GB ram I compiled a big mem kernel, but the
machine is very slow while running big mem kernel. It takes about 37
minutes to compile the intel e1000 driver  (e1000-7.6.5.tar.gz) from
intel site. But it's performing normally when using a non big mem
kernel. The diff of the .config between working and non working is as
follows.

--- config-nobigmem     2007-10-24 12:51:42.000000000 +0530
+++ config-bigmem       2007-10-24 12:48:56.000000000 +0530
@@ -1,7 +1,7 @@
 #
 # Automatically generated make config: don't edit
 # Linux kernel version: 2.6.23.1
-# Wed Oct 24 12:50:21 2007
+# Tue Oct 23 18:08:30 2007
 #
 CONFIG_X86_32=y
 CONFIG_GENERIC_TIME=y
@@ -189,10 +189,11 @@
 CONFIG_DELL_RBU=m
 CONFIG_DCDBAS=m
 CONFIG_DMIID=y
-CONFIG_NOHIGHMEM=y
+# CONFIG_NOHIGHMEM is not set
 # CONFIG_HIGHMEM4G is not set
-# CONFIG_HIGHMEM64G is not set
+CONFIG_HIGHMEM64G=y
 CONFIG_PAGE_OFFSET=0xC0000000
+CONFIG_HIGHMEM=y
 CONFIG_X86_PAE=y
 CONFIG_ARCH_FLATMEM_ENABLE=y
 CONFIG_ARCH_SPARSEMEM_ENABLE=y
@@ -211,6 +212,7 @@
 CONFIG_BOUNCE=y
 CONFIG_NR_QUICK=1
 CONFIG_VIRT_TO_BUS=y
+# CONFIG_HIGHPTE is not set
 # CONFIG_MATH_EMULATION is not set
 CONFIG_MTRR=y
 CONFIG_EFI=y
@@ -223,11 +225,13 @@
 # CONFIG_HZ_1000 is not set
 CONFIG_HZ=250
 CONFIG_KEXEC=y
+# CONFIG_CRASH_DUMP is not set
 CONFIG_PHYSICAL_START=0x100000
 # CONFIG_RELOCATABLE is not set
 CONFIG_PHYSICAL_ALIGN=0x100000
 CONFIG_HOTPLUG_CPU=y
 CONFIG_COMPAT_VDSO=y
+CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG=y

 #
 # Power management options (ACPI, APM)
@@ -1283,6 +1287,7 @@
 CONFIG_I2O=m
 CONFIG_I2O_LCT_NOTIFY_ON_CHANGES=y
 CONFIG_I2O_EXT_ADAPTEC=y
+CONFIG_I2O_EXT_ADAPTEC_DMA64=y
 CONFIG_I2O_CONFIG=m
 CONFIG_I2O_CONFIG_OLD_IOCTL=y
 CONFIG_I2O_BUS=m
@@ -3323,6 +3328,7 @@
 # CONFIG_DEBUG_SPINLOCK_SLEEP is not set
 # CONFIG_DEBUG_LOCKING_API_SELFTESTS is not set
 # CONFIG_DEBUG_KOBJECT is not set
+# CONFIG_DEBUG_HIGHMEM is not set
 CONFIG_DEBUG_BUGVERBOSE=y
 # CONFIG_DEBUG_INFO is not set
 # CONFIG_DEBUG_VM is not set

I was having this same issue with debian kernel also (2.6.22-2-686),
ie stock kernel will work, but big mem is slow. Which is why I tried
latest kernel.

I am posting the full .config at http://pastebin.ca/747758 dmesg while
booting big mem kernel is at http://pastebin.ca/747766

raj