<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi All,<div><br></div><div>We're running Xen enabled Hardy LTS 8.04 on an 8Gb ASUS P5QL VM machine. We are finding that with memory remapping off the OS does not see the whole 8Gb, but with memory remapping on it sees 8Gb. I have no idea really, but I thought that memory remapping only applied to PAE 32bit linux. I've seen various posts regarding the CONFIG_HIGHMEM64G setting be on in order for Ubuntu to see > 4Gb, but am confused as to whether this applies only to PAE enabled 32bit Ubuntu. Is this setting required for 64 bit ubuntu also? On our build it is not set:</div><div><br></div><div><div><div>root@?????:/boot# grep CONFIG_HIGHMEM64G config-2.6.24-2*</div><div>root@?????:/boot# </div><div><br></div><div>I've put the relevant bits of free -m and lshw below.</div><div><br></div><div>Thanks</div><div>Brendan</div><div><br></div><div><br></div></div></div><div>Further details:</div><div><br></div><div><div><b># uname -a:</b></div><div>Linux wkr05 2.6.24-25-xen #1 SMP Tue Oct 20 08:47:34 UTC 2009 x86_64 GNU/Linux</div></div><div><br></div><div><b># free -m with memory remapping on:</b></div><div><div># free -m</div><div> total used free shared buffers cached</div><div>Mem: 7833 350 7483 0 5 62</div><div>-/+ buffers/cache: 281 7551</div><div>Swap: 12401 0 12401</div><div><br></div><div><b># free -m with memory remapping off:</b></div><div><br></div><div><div># free -m</div><div> total used free shared buffers cached</div><div>Mem: 3104 255 2848 0 4 60</div><div>-/+ buffers/cache: 190 2913</div><div>Swap: 12401 0 12401</div><div><br></div></div></div><div><br></div><div><b># Relevant bit of lshw</b></div><div># lshw</div><div><br></div><div><div> *-cpu:0</div><div> product: Intel(R) Core(TM)2 CPU 6400 @ 2.13GHz</div><div> vendor: Intel Corp.</div><div> physical id: 1</div><div> bus info: cpu@0</div><div> width: 64 bits</div><div> capabilities: fpu fpu_exception wp de tsc msr pae mce cx8 apic sep mtrr mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx x86-64 constant_tsc arch_perfmon pebs bts rep_good pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm</div><div> *-cpu:1</div><div> product: Intel(R) Core(TM)2 CPU 6400 @ 2.13GHz</div><div> vendor: Intel Corp.</div><div> physical id: 2</div><div> bus info: cpu@1</div><div> width: 64 bits</div><div> capabilities: fpu fpu_exception wp de tsc msr pae mce cx8 apic sep mtrr mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx x86-64 constant_tsc arch_perfmon pebs bts rep_good pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm</div><div><br></div><div><br></div><div><div>*-memory</div><div> description: System Memory</div><div> physical id: 31</div><div> slot: System board or motherboard</div><div> size: 8GiB</div><div> *-bank:0</div><div> description: DIMM Synchronous 800 MHz (1.2 ns)</div><div> product: ModulePartNumber00</div><div> vendor: Manufacturer00</div><div> physical id: 0</div><div> serial: SerNum00</div><div> slot: DIMM0</div><div> size: 2GiB</div><div> width: 64 bits</div><div> clock: 800MHz (1.2ns)</div><div> *-bank:1</div><div> description: DIMM Synchronous 800 MHz (1.2 ns)</div><div> product: ModulePartNumber01</div><div> vendor: Manufacturer01</div><div> physical id: 1</div><div> serial: SerNum01</div><div> slot: DIMM1</div><div> size: 2GiB</div><div> width: 64 bits</div><div> clock: 800MHz (1.2ns)</div><div> *-bank:2</div><div> description: DIMM Synchronous 800 MHz (1.2 ns)</div><div> product: ModulePartNumber02</div><div> vendor: Manufacturer02</div><div> physical id: 2</div><div> serial: SerNum02</div><div> slot: DIMM2</div><div> size: 2GiB</div><div> width: 64 bits</div><div> clock: 800MHz (1.2ns)</div><div> *-bank:3</div><div> description: DIMM Synchronous 800 MHz (1.2 ns)</div><div> product: ModulePartNumber03</div><div> vendor: Manufacturer03</div><div> physical id: 3</div><div> serial: SerNum03</div><div> slot: DIMM3</div><div> size: 2GiB</div><div> width: 64 bits</div><div> clock: 800MHz (1.2ns)</div><div><br></div></div></div></body></html>