the system is very slow when 4Gb in (high memory support) is seelected when selected none evrething is fine but i have 1024MB RAM and when none selected only ~900 is visible Reproducible: Always Steps to Reproduce: 1.make menuconfig (and select 4GB in High memory support) 2.reboot in new kernel 3. lspci 00:00.0 Host bridge: Intel Corporation 82852/82855 GM/GME/PM/GMV Processor to I/O Controller (rev 02) 00:00.1 System peripheral: Intel Corporation 82852/82855 GM/GME/PM/GMV Processor to I/O Controller (rev 02) 00:00.3 System peripheral: Intel Corporation 82852/82855 GM/GME/PM/GMV Processor to I/O Controller (rev 02) 00:02.0 VGA compatible controller: Intel Corporation 82852/855GM Integrated Graphics Device (rev 02) 00:02.1 Display controller: Intel Corporation 82852/855GM Integrated Graphics Device (rev 02) 00:1d.0 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #1 (rev 03) 00:1d.1 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #2 (rev 03) 00:1d.2 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #3 (rev 03) 00:1d.7 USB Controller: Intel Corporation 82801DB/DBM (ICH4/ICH4-M) USB2 EHCI Controller (rev 03) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev 83) 00:1f.0 ISA bridge: Intel Corporation 82801DBM (ICH4-M) LPC Interface Bridge (rev 03) 00:1f.1 IDE interface: Intel Corporation 82801DBM (ICH4-M) IDE Controller (rev 03) 00:1f.5 Multimedia audio controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Audio Controller (rev 03) 00:1f.6 Modem: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Modem Controller (rev 03) 01:04.0 Network controller: Intel Corporation PRO/Wireless 2200BG Network Connection (rev 05) 01:05.0 CardBus bridge: O2 Micro, Inc. OZ711M1/MC1 4-in-1 MemoryCardBus Controller (rev 20) 01:05.1 CardBus bridge: O2 Micro, Inc. OZ711M1/MC1 4-in-1 MemoryCardBus Controller (rev 20) 01:05.2 System peripheral: O2 Micro, Inc. OZ711Mx 4-in-1 MemoryCardBus Accelerator 01:06.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10) cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 9 model name : Intel(R) Celeron(R) M processor 1300MHz stepping : 5 cpu MHz : 1299.893 cache size : 512 KB fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 2 wp : yes flags : fpu vme de pse tsc msr mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr sse sse2 tm pbe bogomips : 2601.35 clflush size : 64
i forget to say that this bug is present in vanilla-sources-2.6.22.9 and suspend2-sources-2.6.22-r2 gentoo-sources-latest-stable :) is too
I will give you good odds that this is a mtrr issue, caused by the BIOS. This manifests when certain portions of your memory are not cacheable due to a bug in BIOS. Please post the output of cat /proc/mtrr when HIGHMEM is enabled. I suspect it will show something like this: http://lkml.org/lkml/2003/11/9/79 >cat /proc/mtrr: >reg00: base=0x00000000 ( 0MB), size= 512MB: write-back, count=1 >reg01: base=0x20000000 ( 512MB), size= 256MB: write-back, count=1 >reg02: base=0x30000000 ( 768MB), size= 128MB: write-back, count=1 >reg03: base=0x38000000 ( 896MB), size= 64MB: write-back, count=1 >reg04: base=0x3c000000 ( 960MB), size= 32MB: write-back, count=1 >reg05: base=0x3e000000 ( 992MB), size= 16MB: write-back, count=1 >reg06: base=0xf0000000 (3840MB), size= 128MB: write-combining, count=1 As you can see, that leaves 1024-1008=16 MB uncacheable. If so, try booting with mem=1008 on the grub command line. There probably exists an upgrade for your BIOS that solves this completely.
