I've noticed that with 4GB physical ram, I'm only see 3098000 MB on the Dell 745, and 3107056MB on the IBM X60s.
I've tested with CONFIG_HIGHMEM4G=y, CONFIG_HIGHMEM64G=y, CONFIG_X86_PAE=y, but nothing makes any difference. Tested on Linux 2.6.20, Linux 2.6.21-rc7. # dmesg copy_e820_map() start: 0000000000000000 size: 000000000009f000 end: 000000000009f000 type: 1 copy_e820_map() type is E820_RAM copy_e820_map() start: 000000000009f000 size: 0000000000001000 end: 00000000000a0000 type: 2 copy_e820_map() start: 00000000000dc000 size: 0000000000024000 end: 0000000000100000 type: 2 copy_e820_map() start: 0000000000100000 size: 00000000bf5d0000 end: 00000000bf6d0000 type: 1 copy_e820_map() type is E820_RAM copy_e820_map() start: 00000000bf6d0000 size: 000000000000f000 end: 00000000bf6df000 type: 3 copy_e820_map() start: 00000000bf6df000 size: 0000000000021000 end: 00000000bf700000 type: 4 copy_e820_map() start: 00000000bf700000 size: 0000000000900000 end: 00000000c0000000 type: 2 copy_e820_map() start: 00000000f0000000 size: 0000000004000000 end: 00000000f4000000 type: 2 copy_e820_map() start: 00000000fec00000 size: 0000000000010000 end: 00000000fec10000 type: 2 copy_e820_map() start: 00000000fed00000 size: 0000000000000400 end: 00000000fed00400 type: 2 copy_e820_map() start: 00000000fed14000 size: 0000000000006000 end: 00000000fed1a000 type: 2 copy_e820_map() start: 00000000fed1c000 size: 0000000000074000 end: 00000000fed90000 type: 2 copy_e820_map() start: 00000000fee00000 size: 0000000000001000 end: 00000000fee01000 type: 2 copy_e820_map() start: 00000000ff800000 size: 0000000000800000 end: 0000000100000000 type: 2 BIOS-e820: 0000000000000000 - 000000000009f000 (usable) BIOS-e820: 000000000009f000 - 00000000000a0000 (reserved) BIOS-e820: 00000000000dc000 - 0000000000100000 (reserved) BIOS-e820: 0000000000100000 - 00000000bf6d0000 (usable) BIOS-e820: 00000000bf6d0000 - 00000000bf6df000 (ACPI data) BIOS-e820: 00000000bf6df000 - 00000000bf700000 (ACPI NVS) BIOS-e820: 00000000bf700000 - 00000000c0000000 (reserved) BIOS-e820: 00000000f0000000 - 00000000f4000000 (reserved) BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved) BIOS-e820: 00000000fed00000 - 00000000fed00400 (reserved) BIOS-e820: 00000000fed14000 - 00000000fed1a000 (reserved) BIOS-e820: 00000000fed1c000 - 00000000fed90000 (reserved) BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved) BIOS-e820: 00000000ff800000 - 0000000100000000 (reserved) 2166MB HIGHMEM available. 896MB LOWMEM available. Memory: 3106140k/3136320k available (2225k kernel code, 29072k reserved, 910k data, 196k init, 2218816k highmem) virtual kernel memory layout: fixmap : 0xfff50000 - 0xfffff000 ( 700 kB) pkmap : 0xff800000 - 0xffc00000 (4096 kB) vmalloc : 0xf8800000 - 0xff7fe000 ( 111 MB) lowmem : 0xc0000000 - 0xf8000000 ( 896 MB) .init : 0xc0416000 - 0xc0447000 ( 196 kB) .data : 0xc032c513 - 0xc040ff34 ( 910 kB) .text : 0xc0100000 - 0xc032c513 (2225 kB) Thanks, Jeff. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/