Good Day All, Today I looked at the dmesg log and I notice that the following messages regarding mtrr_gran_size/mtrr_chunk_size. I am currently running CentOS 6.3 and I installed CentOS 6.2 and 6.1 and I was seeing the same errors. When I installed CentOS 5.8 on the same laptop I do not see these errors. $ lsb_release -a LSB Version: :core-4.0-amd64:core-4.0-noarch:graphics-4.0-amd64:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-noarch Distributor ID: CentOS Description: CentOS release 6.3 (Final) Release: 6.3 Codename: Final Below is an excerpt from dmesg BIOS-provided physical RAM map: BIOS-e820: 0000000000000000 - 000000000009e800 (usable) BIOS-e820: 000000000009e800 - 00000000000a0000 (reserved) BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved) BIOS-e820: 0000000000100000 - 0000000020000000 (usable) BIOS-e820: 0000000020000000 - 0000000020200000 (reserved) BIOS-e820: 0000000020200000 - 0000000040000000 (usable) BIOS-e820: 0000000040000000 - 0000000040200000 (reserved) BIOS-e820: 0000000040200000 - 00000000aac0c000 (usable) BIOS-e820: 00000000aac0c000 - 00000000aad8e000 (reserved) BIOS-e820: 00000000aad8e000 - 00000000aad94000 (usable) BIOS-e820: 00000000aad94000 - 00000000aad95000 (reserved) BIOS-e820: 00000000aad95000 - 00000000aad96000 (usable) BIOS-e820: 00000000aad96000 - 00000000aadb8000 (reserved) BIOS-e820: 00000000aadb8000 - 00000000aadc6000 (usable) BIOS-e820: 00000000aadc6000 - 00000000aade8000 (reserved) BIOS-e820: 00000000aade8000 - 00000000aae22000 (usable) BIOS-e820: 00000000aae22000 - 00000000aafe8000 (ACPI NVS) BIOS-e820: 00000000aafe8000 - 00000000aaffd000 (usable) BIOS-e820: 00000000aaffd000 - 00000000ab000000 (ACPI data) BIOS-e820: 00000000ab000000 - 00000000b0000000 (reserved) BIOS-e820: 00000000e0000000 - 00000000e4000000 (reserved) BIOS-e820: 00000000fec00000 - 00000000fec01000 (reserved) BIOS-e820: 00000000fed10000 - 00000000fed14000 (reserved) BIOS-e820: 00000000fed18000 - 00000000fed1a000 (reserved) BIOS-e820: 00000000fed1c000 - 00000000fed20000 (reserved) BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved) BIOS-e820: 00000000ff980000 - 00000000ffc00000 (reserved) BIOS-e820: 00000000ffd80000 - 0000000100000000 (reserved) BIOS-e820: 0000000100000000 - 000000044f800000 (usable) DMI 2.6 present. SMBIOS version 2.6 @ 0xF0460 DMI: ASUSTeK Computer Inc. N55SL/N55SL, BIOS N55SL.201 11/10/2011 AMI BIOS detected: BIOS may corrupt low RAM, working around it. e820 update range: 0000000000000000 - 0000000000010000 (usable) ==> (reserved) e820 update range: 0000000000000000 - 0000000000001000 (usable) ==> (reserved) e820 remove range: 00000000000a0000 - 0000000000100000 (usable) last_pfn = 0x44f800 max_arch_pfn = 0x400000000 MTRR default type: uncachable MTRR fixed ranges enabled: 00000-9FFFF write-back A0000-BFFFF uncachable C0000-CFFFF write-protect D0000-E7FFF uncachable E8000-FFFFF write-protect MTRR variable ranges enabled: 0 base 000000000 mask C00000000 write-back 1 base 400000000 mask FC0000000 write-back 2 base 440000000 mask FF0000000 write-back 3 base 0C0000000 mask FC0000000 uncachable 4 base 0B0000000 mask FF0000000 uncachable 5 base 0AC000000 mask FFC000000 uncachable 6 base 0AB000000 mask FFF000000 uncachable 7 base 44F800000 mask FFF800000 uncachable 8 disabled 9 disabled x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106 original variable MTRRs reg 0, base: 0GB, range: 16GB, type WB reg 1, base: 16GB, range: 1GB, type WB reg 2, base: 17GB, range: 256MB, type WB reg 3, base: 3GB, range: 1GB, type UC reg 4, base: 2816MB, range: 256MB, type UC reg 5, base: 2752MB, range: 64MB, type UC reg 6, base: 2736MB, range: 16MB, type UC reg 7, base: 17656MB, range: 8MB, type UC total RAM covered: 16296M gran_size: 64K chunk_size: 64K num_reg: 10 lose cover RAM: 56M gran_size: 64K chunk_size: 128K num_reg: 10 lose cover RAM: 56M gran_size: 64K chunk_size: 256K num_reg: 10 lose cover RAM: 56M gran_size: 64K chunk_size: 512K num_reg: 10 lose cover RAM: 56M gran_size: 64K chunk_size: 1M num_reg: 10 lose cover RAM: 56M gran_size: 64K chunk_size: 2M num_reg: 10 lose cover RAM: 56M gran_size: 64K chunk_size: 4M num_reg: 10 lose cover RAM: 56M gran_size: 64K chunk_size: 8M num_reg: 10 lose cover RAM: 56M gran_size: 64K chunk_size: 16M num_reg: 10 lose cover RAM: 0G gran_size: 64K chunk_size: 32M num_reg: 10 lose cover RAM: 0G gran_size: 64K chunk_size: 64M num_reg: 10 lose cover RAM: 0G gran_size: 64K chunk_size: 128M num_reg: 10 lose cover RAM: 0G gran_size: 64K chunk_size: 256M num_reg: 10 lose cover RAM: 0G *BAD*gran_size: 64K chunk_size: 512M num_reg: 10 lose cover RAM: -256M *BAD*gran_size: 64K chunk_size: 1G num_reg: 10 lose cover RAM: -512M *BAD*gran_size: 64K chunk_size: 2G num_reg: 10 lose cover RAM: -512M gran_size: 128K chunk_size: 128K num_reg: 10 lose cover RAM: 56M gran_size: 128K chunk_size: 256K num_reg: 10 lose cover RAM: 56M gran_size: 128K chunk_size: 512K num_reg: 10 lose cover RAM: 56M gran_size: 128K chunk_size: 1M num_reg: 10 lose cover RAM: 56M gran_size: 128K chunk_size: 2M num_reg: 10 lose cover RAM: 56M gran_size: 128K chunk_size: 4M num_reg: 10 lose cover RAM: 56M gran_size: 128K chunk_size: 8M num_reg: 10 lose cover RAM: 56M gran_size: 128K chunk_size: 16M num_reg: 10 lose cover RAM: 0G gran_size: 128K chunk_size: 32M num_reg: 10 lose cover RAM: 0G gran_size: 128K chunk_size: 64M num_reg: 10 lose cover RAM: 0G gran_size: 128K chunk_size: 128M num_reg: 10 lose cover RAM: 0G gran_size: 128K chunk_size: 256M num_reg: 10 lose cover RAM: 0G *BAD*gran_size: 128K chunk_size: 512M num_reg: 10 lose cover RAM: -256M *BAD*gran_size: 128K chunk_size: 1G num_reg: 10 lose cover RAM: -512M *BAD*gran_size: 128K chunk_size: 2G num_reg: 10 lose cover RAM: -512M gran_size: 256K chunk_size: 256K num_reg: 10 lose cover RAM: 56M gran_size: 256K chunk_size: 512K num_reg: 10 lose cover RAM: 56M gran_size: 256K chunk_size: 1M num_reg: 10 lose cover RAM: 56M gran_size: 256K chunk_size: 2M num_reg: 10 lose cover RAM: 56M gran_size: 256K chunk_size: 4M num_reg: 10 lose cover RAM: 56M gran_size: 256K chunk_size: 8M num_reg: 10 lose cover RAM: 56M gran_size: 256K chunk_size: 16M num_reg: 10 lose cover RAM: 0G gran_size: 256K chunk_size: 32M num_reg: 10 lose cover RAM: 0G gran_size: 256K chunk_size: 64M num_reg: 10 lose cover RAM: 0G gran_size: 256K chunk_size: 128M num_reg: 10 lose cover RAM: 0G gran_size: 256K chunk_size: 256M num_reg: 10 lose cover RAM: 0G *BAD*gran_size: 256K chunk_size: 512M num_reg: 10 lose cover RAM: -256M *BAD*gran_size: 256K chunk_size: 1G num_reg: 10 lose cover RAM: -512M *BAD*gran_size: 256K chunk_size: 2G num_reg: 10 lose cover RAM: -512M gran_size: 512K chunk_size: 512K num_reg: 10 lose cover RAM: 56M gran_size: 512K chunk_size: 1M num_reg: 10 lose cover RAM: 56M gran_size: 512K chunk_size: 2M num_reg: 10 lose cover RAM: 56M gran_size: 512K chunk_size: 4M num_reg: 10 lose cover RAM: 56M gran_size: 512K chunk_size: 8M num_reg: 10 lose cover RAM: 56M gran_size: 512K chunk_size: 16M num_reg: 10 lose cover RAM: 0G gran_size: 512K chunk_size: 32M num_reg: 10 lose cover RAM: 0G gran_size: 512K chunk_size: 64M num_reg: 10 lose cover RAM: 0G gran_size: 512K chunk_size: 128M num_reg: 10 lose cover RAM: 0G gran_size: 512K chunk_size: 256M num_reg: 10 lose cover RAM: 0G *BAD*gran_size: 512K chunk_size: 512M num_reg: 10 lose cover RAM: -256M *BAD*gran_size: 512K chunk_size: 1G num_reg: 10 lose cover RAM: -512M *BAD*gran_size: 512K chunk_size: 2G num_reg: 10 lose cover RAM: -512M gran_size: 1M chunk_size: 1M num_reg: 10 lose cover RAM: 56M gran_size: 1M chunk_size: 2M num_reg: 10 lose cover RAM: 56M gran_size: 1M chunk_size: 4M num_reg: 10 lose cover RAM: 56M gran_size: 1M chunk_size: 8M num_reg: 10 lose cover RAM: 56M gran_size: 1M chunk_size: 16M num_reg: 10 lose cover RAM: 0G gran_size: 1M chunk_size: 32M num_reg: 10 lose cover RAM: 0G gran_size: 1M chunk_size: 64M num_reg: 10 lose cover RAM: 0G gran_size: 1M chunk_size: 128M num_reg: 10 lose cover RAM: 0G gran_size: 1M chunk_size: 256M num_reg: 10 lose cover RAM: 0G *BAD*gran_size: 1M chunk_size: 512M num_reg: 10 lose cover RAM: -256M *BAD*gran_size: 1M chunk_size: 1G num_reg: 10 lose cover RAM: -512M *BAD*gran_size: 1M chunk_size: 2G num_reg: 10 lose cover RAM: -512M gran_size: 2M chunk_size: 2M num_reg: 10 lose cover RAM: 56M gran_size: 2M chunk_size: 4M num_reg: 10 lose cover RAM: 56M gran_size: 2M chunk_size: 8M num_reg: 10 lose cover RAM: 56M gran_size: 2M chunk_size: 16M num_reg: 10 lose cover RAM: 0G gran_size: 2M chunk_size: 32M num_reg: 10 lose cover RAM: 0G gran_size: 2M chunk_size: 64M num_reg: 10 lose cover RAM: 0G gran_size: 2M chunk_size: 128M num_reg: 10 lose cover RAM: 0G gran_size: 2M chunk_size: 256M num_reg: 10 lose cover RAM: 0G *BAD*gran_size: 2M chunk_size: 512M num_reg: 10 lose cover RAM: -256M *BAD*gran_size: 2M chunk_size: 1G num_reg: 10 lose cover RAM: -512M *BAD*gran_size: 2M chunk_size: 2G num_reg: 10 lose cover RAM: -512M gran_size: 4M chunk_size: 4M num_reg: 10 lose cover RAM: 56M gran_size: 4M chunk_size: 8M num_reg: 10 lose cover RAM: 56M gran_size: 4M chunk_size: 16M num_reg: 10 lose cover RAM: 0G gran_size: 4M chunk_size: 32M num_reg: 10 lose cover RAM: 0G gran_size: 4M chunk_size: 64M num_reg: 10 lose cover RAM: 0G gran_size: 4M chunk_size: 128M num_reg: 10 lose cover RAM: 0G gran_size: 4M chunk_size: 256M num_reg: 10 lose cover RAM: 0G *BAD*gran_size: 4M chunk_size: 512M num_reg: 10 lose cover RAM: -256M *BAD*gran_size: 4M chunk_size: 1G num_reg: 10 lose cover RAM: -512M *BAD*gran_size: 4M chunk_size: 2G num_reg: 10 lose cover RAM: -512M gran_size: 8M chunk_size: 8M num_reg: 10 lose cover RAM: 56M gran_size: 8M chunk_size: 16M num_reg: 10 lose cover RAM: 0G gran_size: 8M chunk_size: 32M num_reg: 10 lose cover RAM: 0G gran_size: 8M chunk_size: 64M num_reg: 10 lose cover RAM: 0G gran_size: 8M chunk_size: 128M num_reg: 10 lose cover RAM: 0G gran_size: 8M chunk_size: 256M num_reg: 10 lose cover RAM: 0G *BAD*gran_size: 8M chunk_size: 512M num_reg: 10 lose cover RAM: -256M *BAD*gran_size: 8M chunk_size: 1G num_reg: 10 lose cover RAM: -512M *BAD*gran_size: 8M chunk_size: 2G num_reg: 10 lose cover RAM: -512M gran_size: 16M chunk_size: 16M num_reg: 10 lose cover RAM: 56M gran_size: 16M chunk_size: 32M num_reg: 10 lose cover RAM: 8M gran_size: 16M chunk_size: 64M num_reg: 10 lose cover RAM: 8M gran_size: 16M chunk_size: 128M num_reg: 10 lose cover RAM: 8M gran_size: 16M chunk_size: 256M num_reg: 10 lose cover RAM: 8M *BAD*gran_size: 16M chunk_size: 512M num_reg: 10 lose cover RAM: -248M *BAD*gran_size: 16M chunk_size: 1G num_reg: 10 lose cover RAM: -504M *BAD*gran_size: 16M chunk_size: 2G num_reg: 10 lose cover RAM: -504M gran_size: 32M chunk_size: 32M num_reg: 10 lose cover RAM: 40M gran_size: 32M chunk_size: 64M num_reg: 10 lose cover RAM: 40M gran_size: 32M chunk_size: 128M num_reg: 10 lose cover RAM: 40M gran_size: 32M chunk_size: 256M num_reg: 10 lose cover RAM: 40M *BAD*gran_size: 32M chunk_size: 512M num_reg: 10 lose cover RAM: -216M *BAD*gran_size: 32M chunk_size: 1G num_reg: 10 lose cover RAM: -472M *BAD*gran_size: 32M chunk_size: 2G num_reg: 10 lose cover RAM: -472M gran_size: 64M chunk_size: 64M num_reg: 8 lose cover RAM: 104M gran_size: 64M chunk_size: 128M num_reg: 8 lose cover RAM: 104M gran_size: 64M chunk_size: 256M num_reg: 9 lose cover RAM: 104M gran_size: 64M chunk_size: 512M num_reg: 10 lose cover RAM: 104M gran_size: 64M chunk_size: 1G num_reg: 10 lose cover RAM: 104M gran_size: 64M chunk_size: 2G num_reg: 10 lose cover RAM: 104M gran_size: 128M chunk_size: 128M num_reg: 7 lose cover RAM: 168M gran_size: 128M chunk_size: 256M num_reg: 9 lose cover RAM: 168M gran_size: 128M chunk_size: 512M num_reg: 10 lose cover RAM: 168M gran_size: 128M chunk_size: 1G num_reg: 10 lose cover RAM: 168M gran_size: 128M chunk_size: 2G num_reg: 10 lose cover RAM: 168M gran_size: 256M chunk_size: 256M num_reg: 5 lose cover RAM: 424M gran_size: 256M chunk_size: 512M num_reg: 5 lose cover RAM: 424M gran_size: 256M chunk_size: 1G num_reg: 6 lose cover RAM: 424M gran_size: 256M chunk_size: 2G num_reg: 7 lose cover RAM: 424M gran_size: 512M chunk_size: 512M num_reg: 5 lose cover RAM: 424M gran_size: 512M chunk_size: 1G num_reg: 6 lose cover RAM: 424M gran_size: 512M chunk_size: 2G num_reg: 7 lose cover RAM: 424M gran_size: 1G chunk_size: 1G num_reg: 4 lose cover RAM: 936M gran_size: 1G chunk_size: 2G num_reg: 5 lose cover RAM: 936M gran_size: 2G chunk_size: 2G num_reg: 3 lose cover RAM: 1960M mtrr_cleanup: can not find optimal value please specify mtrr_gran_size/mtrr_chunk_size e820 update range: 00000000ab000000 - 0000000100000000 (usable) ==> (reserved) last_pfn = 0xaaffd max_arch_pfn = 0x400000000 initial memory mapped : 0 - 20000000 init_memory_mapping: 0000000000000000-00000000aaffd000 0000000000 - 00aae00000 page 2M 00aae00000 - 00aaffd000 page 4k kernel direct mapping tables up to aaffd000 @ 10000-15000 init_memory_mapping: 0000000100000000-000000044f800000 0100000000 - 044f800000 page 2M kernel direct mapping tables up to 44f800000 @ 13000-26000 My Laptop currently has 16GB of RAM and 8GB of swap as indicated below $ cat /proc/meminfo MemTotal: 16235284 kB MemFree: 15024984 kB Buffers: 28128 kB Cached: 412944 kB SwapCached: 134284 kB Active: 404240 kB Inactive: 440124 kB Active(anon): 224792 kB Inactive(anon): 230964 kB Active(file): 179448 kB Inactive(file): 209160 kB Unevictable: 0 kB Mlocked: 0 kB SwapTotal: 8388600 kB SwapFree: 7555824 kB Dirty: 8 kB Writeback: 0 kB AnonPages: 291668 kB Mapped: 45216 kB Shmem: 52452 kB Slab: 120600 kB SReclaimable: 32100 kB SUnreclaim: 88500 kB KernelStack: 4344 kB PageTables: 35824 kB NFS_Unstable: 0 kB Bounce: 0 kB WritebackTmp: 0 kB CommitLimit: 16506240 kB Committed_AS: 3714116 kB VmallocTotal: 34359738367 kB VmallocUsed: 393260 kB VmallocChunk: 34359332704 kB HardwareCorrupted: 0 kB AnonHugePages: 165888 kB HugePages_Total: 0 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB DirectMap4k: 10228 kB DirectMap2M: 16676864 kB $ cat /proc/swaps Filename Type Size Used Priority /dev/dm-0 partition 8388600 832688 -1 The laptop is running the latest updates and kernel $ uname -r 2.6.32-279.11.1.el6.x86_64 I saw that this was a bug from Fedora 14 and CentOS as well, however it does not appear to be resolved. https://bugzilla.redhat.com/show_bug.cgi?id=584493 http://bugs.centos.org/view.php?id=5659 At random times my laptop will just lock up and I will have to power cycle it, I don't know if this is related. I had CentOS 5.8 installed for over a week and I did not experience this behaviour. Do I need file this as a new bug or is there a solution for this? -- Kind Regards Earl Ramirez