我已经为这个问题苦苦挣扎了很长时间，完全没有主意了。我安装了 8GB 内存，但 ubuntu 只看到 3.2 GB。
硬件：
Mother Board Information
Intel DG965SS
Processor Information
Socket Designation: LGA 775
Type: Central Processor
Family: Core 2
Manufacturer: Intel(R) Corporation
ID: F6 06 00 00 FF FB EB BF
Signature: Type 0, Family 6, Model 15, Stepping 6
Flags:
FPU (Floating-point unit on-chip)
VME (Virtual mode extension)
DE (Debugging extension)
PSE (Page size extension)
TSC (Time stamp counter)
MSR (Model specific registers)
PAE (Physical address extension)
MCE (Machine check exception)
CX8 (CMPXCHG8 instruction supported)
APIC (On-chip APIC hardware supported)
SEP (Fast system call)
MTRR (Memory type range registers)
PGE (Page global enable)
MCA (Machine check architecture)
CMOV (Conditional move instruction supported)
PAT (Page attribute table)
PSE-36 (36-bit page size extension)
CLFSH (CLFLUSH instruction supported)
DS (Debug store)
ACPI (ACPI supported)
MMX (MMX technology supported)
FXSR (FXSAVE and FXSTOR instructions supported)
SSE (Streaming SIMD extensions)
SSE2 (Streaming SIMD extensions 2)
SS (Self-snoop)
HTT (Multi-threading)
TM (Thermal monitor supported)
PBE (Pending break enabled)
Version: Intel(R) Core(TM)2 CPU 6400 @ 2.13GHz
Voltage: 1.6 V
External Clock: 266 MHz
Max Speed: 4000 MHz
Current Speed: 2133 MHz
Status: Populated, Enabled
Upgrade: Socket LGA775
L1 Cache Handle: 0x0003
L2 Cache Handle: 0x0001
L3 Cache Handle: Not Provided
Serial Number: Not Specified
Asset Tag: Not Specified
Part Number: Not Specified
BIOS Information
Vendor: Intel Corp.
Version: MQ96510J.86A.1687.2007.0510.0258
Release Date: 05/10/2007
Address: 0xF0000
Runtime Size: 64 kB
ROM Size: 1024 kB
Characteristics:
PCI is supported
BIOS is upgradeable
BIOS shadowing is allowed
Boot from CD is supported
Selectable boot is supported
EDD is supported
8042 keyboard services are supported (int 9h)
Serial services are supported (int 14h)
Printer services are supported (int 17h)
CGA/mono video services are supported (int 10h)
ACPI is supported
USB legacy is supported
ATAPI Zip drive boot is supported
BIOS boot specification is supported
Function key-initiated network boot is supported
Targeted content distribution is supported
BIOS Revision: 0.0
Firmware Revision: 0.0
Physical Memory Array
Location: System Board Or Motherboard
Use: System Memory
Error Correction Type: None
Maximum Capacity: 8 GB
Error Information Handle: Not Provided
Number Of Devices: 4
Handle 0x0015, DMI type 17, 27 bytes
Memory Device
Array Handle: 0x0014
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 2048 MB
Form Factor: DIMM
Set: None
Locator: J6H1
Bank Locator: CHAN A DIMM 0
Type: DDR2
Type Detail: Synchronous
Speed: 667 MHz
Manufacturer: 0x7F7F7F0B00000000
Serial Number: 0xDD0A0443
Asset Tag: Unknown
Part Number: 0x4E54324754363455384842304A592D334320
Handle 0x0016, DMI type 20, 19 bytes
Memory Device Mapped Address
Starting Address: 0x00000000000
Ending Address: 0x0007FFFFFFF
Range Size: 2 GB
Physical Device Handle: 0x0015
Memory Array Mapped Address Handle: 0x001D
Partition Row Position: 1
Interleave Position: 1
Interleaved Data Depth: 1
Handle 0x0017, DMI type 17, 27 bytes
Memory Device
Array Handle: 0x0014
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 2048 MB
Form Factor: DIMM
Set: None
Locator: J6H2
Bank Locator: CHAN A DIMM 1
Type: DDR2
Type Detail: Synchronous
Speed: 667 MHz
Manufacturer: 0x7F7F7F0B00000000
Serial Number: 0xC10B0443
Asset Tag: Unknown
Part Number: 0x4E54324754363455384842304A592D334320
Handle 0x0018, DMI type 20, 19 bytes
Memory Device Mapped Address
Starting Address: 0x00080000000
Ending Address: 0x000FFFFFFFF
Range Size: 2 GB
Physical Device Handle: 0x0017
Memory Array Mapped Address Handle: 0x001D
Partition Row Position: 1
Interleave Position: 1
Interleaved Data Depth: 1
Handle 0x0019, DMI type 17, 27 bytes
Memory Device
Array Handle: 0x0014
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 2048 MB
Form Factor: DIMM
Set: None
Locator: J6J1
Bank Locator: CHAN B DIMM 0
Type: DDR2
Type Detail: Synchronous
Speed: 667 MHz
Manufacturer: 0x7F7F7F7F7F7F7F02
Serial Number: 0x100212C5
Asset Tag: Unknown
Part Number: 0x3235365836344D2D36374500560000000000
Handle 0x001A, DMI type 20, 19 bytes
Memory Device Mapped Address
Starting Address: 0x00100000000
Ending Address: 0x0017FFFFFFF
Range Size: 2 GB
Physical Device Handle: 0x0019
Memory Array Mapped Address Handle: 0x001D
Partition Row Position: 2
Interleave Position: 2
Interleaved Data Depth: 1
Handle 0x001B, DMI type 17, 27 bytes
Memory Device
Array Handle: 0x0014
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 2048 MB
Form Factor: DIMM
Set: None
Locator: J6J2
Bank Locator: CHAN B DIMM 1
Type: DDR2
Type Detail: Synchronous
Speed: 667 MHz
Manufacturer: 0x7F7F7F7F7F7F3400
Serial Number: 0x00000000
Asset Tag: Unknown
Part Number: 0x535550455254414C454E5430310000000000
Handle 0x001C, DMI type 20, 19 bytes
Memory Device Mapped Address
Starting Address: 0x00180000000
Ending Address: 0x001FFFFFFFF
Range Size: 2 GB
Physical Device Handle: 0x001B
Memory Array Mapped Address Handle: 0x001D
Partition Row Position: 2
Interleave Position: 2
Interleaved Data Depth: 1
Handle 0x001D, DMI type 19, 15 bytes
Memory Array Mapped Address
Starting Address: 0x00000000000
Ending Address: 0x001FFFFFFFF
Range Size: 8 GB
Physical Array Handle: 0x0014
Partition Width: 4
尽管安装了所有内存，但当我查看 ubuntu 报告的内存时，它显示：
dmesg | grep "Memory"
[ 0.000000] Memory: 3284664K/3397260K available (8613K kernel code, 1335K rwdata, 4028K rodata, 1484K init, 1284K bss, 112596K reserved, 0K cma-reserved)
[ 2.550918] [drm] Memory usable by graphics device = 512M
free -m
total used free shared buff/cache available
Mem: 3249 1016 289 339 1943 1673
Swap: 17311 0 17311
以下是 dmesg 的输出：
dmesg
[ 0.000000] microcode: CPU0 microcode updated early to revision 0xd0, date = 2010-09-30
[ 0.000000] Initializing cgroup subsys cpuset
[ 0.000000] Initializing cgroup subsys cpu
[ 0.000000] Initializing cgroup subsys cpuacct
[ 0.000000] Linux version 4.4.0-151-generic (buildd@lgw01-amd64-043) (gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.10) ) #178-Ubuntu SMP Tue Jun 11 08:30:22 UTC 2019 (Ubuntu 4.4.0-151.178-generic 4.4.179)
[ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-4.4.0-151-generic root=UUID=29f49899-a2fa-496f-99e8-0d40b69303df ro quiet splash vt.handoff=7
[ 0.000000] KERNEL supported cpus:
[ 0.000000] Intel GenuineIntel
[ 0.000000] AMD AuthenticAMD
[ 0.000000] Centaur CentaurHauls
[ 0.000000] x86/fpu: Legacy x87 FPU detected.
[ 0.000000] e820: BIOS-provided physical RAM map:
[ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000008efff] usable
[ 0.000000] BIOS-e820: [mem 0x000000000008f000-0x000000000009ffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved
[ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000cf560fff] usable
[ 0.000000] BIOS-e820: [mem 0x00000000cf561000-0x00000000cf56dfff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000cf56e000-0x00000000cf61bfff] usable
[ 0.000000] BIOS-e820: [mem 0x00000000cf61c000-0x00000000cf6e8fff] ACPI NVS
[ 0.000000] BIOS-e820: [mem 0x00000000cf6e9000-0x00000000cf6ecfff] usable
[ 0.000000] BIOS-e820: [mem 0x00000000cf6ed000-0x00000000cf6f1fff] ACPI data
[ 0.000000] BIOS-e820: [mem 0x00000000cf6f2000-0x00000000cf6f2fff] usable
[ 0.000000] BIOS-e820: [mem 0x00000000cf6f3000-0x00000000cf6fefff] ACPI data
[ 0.000000] BIOS-e820: [mem 0x00000000cf6ff000-0x00000000cf6fffff] usable
[ 0.000000] BIOS-e820: [mem 0x00000000cf700000-0x00000000cfffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000fff00000-0x00000000ffffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000022bffffff] usable
[ 0.000000] NX (Execute Disable) protection: active
[ 0.000000] SMBIOS 2.4 present.
[ 0.000000] DMI: /DG965SS, BIOS MQ96510J.86A.1687.2007.0510.0258 05/10/2007
[ 0.000000] e820: update [mem 0x00000000-0x00000fff] usable ==> reserved
[ 0.000000] e820: remove [mem 0x000a0000-0x000fffff] usable
[ 0.000000] e820: last_pfn = 0x22c000 max_arch_pfn = 0x400000000
[ 0.000000] MTRR default type: uncachable
[ 0.000000] MTRR fixed ranges enabled:
[ 0.000000] 00000-9FFFF write-back
[ 0.000000] A0000-FFFFF uncachable
[ 0.000000] MTRR variable ranges enabled:
[ 0.000000] 0 base 000000000 mask F80000000 write-back
[ 0.000000] 1 base 080000000 mask FC0000000 write-back
[ 0.000000] 2 base 0C0000000 mask FF0000000 write-back
[ 0.000000] 3 base 0CF800000 mask FFF800000 uncachable
[ 0.000000] 4 base 0CF700000 mask FFFF00000 uncachable
[ 0.000000] 5 disabled
[ 0.000000] 6 disabled
[ 0.000000] 7 disabled
[ 0.000000] x86/PAT: Configuration [0-7]: WB WC UC- UC WB WC UC- WT
[ 0.000000] original variable MTRRs
[ 0.000000] reg 0, base: 0GB, range: 2GB, type WB
[ 0.000000] reg 1, base: 2GB, range: 1GB, type WB
[ 0.000000] reg 2, base: 3GB, range: 256MB, type WB
[ 0.000000] reg 3, base: 3320MB, range: 8MB, type UC
[ 0.000000] reg 4, base: 3319MB, range: 1MB, type UC
[ 0.000000] total RAM covered: 3319M
[ 0.000000] Found optimal setting for mtrr clean up
[ 0.000000] gran_size: 64K chunk_size: 16M num_reg: 5 lose cover RAM: 0G
[ 0.000000] New variable MTRRs
[ 0.000000] reg 0, base: 0GB, range: 2GB, type WB
[ 0.000000] reg 1, base: 2GB, range: 1GB, type WB
[ 0.000000] reg 2, base: 3GB, range: 256MB, type WB
[ 0.000000] reg 3, base: 3319MB, range: 1MB, type UC
[ 0.000000] reg 4, base: 3320MB, range: 8MB, type UC
[ 0.000000] e820: update [mem 0xcf700000-0x22bffffff] usable ==> reserved
[ 0.000000] WARNING: BIOS bug: CPU MTRRs don't cover all of memory, losing 4800MB of RAM.
[ 0.000000] update e820 for mtrr
[ 0.000000] e820: modified physical RAM map:
[ 0.000000] modified: [mem 0x0000000000000000-0x0000000000000fff] reserved
[ 0.000000] modified: [mem 0x0000000000001000-0x000000000008efff] usable
[ 0.000000] modified: [mem 0x000000000008f000-0x000000000009ffff] reserved
[ 0.000000] modified: [mem 0x00000000000e0000-0x00000000000fffff] reserved
[ 0.000000] modified: [mem 0x0000000000100000-0x00000000cf560fff] usable
[ 0.000000] modified: [mem 0x00000000cf561000-0x00000000cf56dfff] reserved
[ 0.000000] modified: [mem 0x00000000cf56e000-0x00000000cf61bfff] usable
[ 0.000000] modified: [mem 0x00000000cf61c000-0x00000000cf6e8fff] ACPI NVS
[ 0.000000] modified: [mem 0x00000000cf6e9000-0x00000000cf6ecfff] usable
[ 0.000000] modified: [mem 0x00000000cf6ed000-0x00000000cf6f1fff] ACPI data
[ 0.000000] modified: [mem 0x00000000cf6f2000-0x00000000cf6f2fff] usable
[ 0.000000] modified: [mem 0x00000000cf6f3000-0x00000000cf6fefff] ACPI data
[ 0.000000] modified: [mem 0x00000000cf6ff000-0x00000000cf6fffff] usable
[ 0.000000] modified: [mem 0x00000000cf700000-0x00000000cfffffff] reserved
[ 0.000000] modified: [mem 0x00000000fff00000-0x000000022bffffff] reserved
[ 0.000000] e820: last_pfn = 0xcf700 max_arch_pfn = 0x400000000
[ 0.000000] found SMP MP-table at [mem 0x000fe200-0x000fe20f] mapped at [ffff8800000fe200]
[ 0.000000] Scanning 1 areas for low memory corruption
[ 0.000000] Base memory trampoline at [ffff880000088000] 88000 size 28672
[ 0.000000] BRK [0x0220e000, 0x0220efff] PGTABLE
[ 0.000000] BRK [0x0220f000, 0x0220ffff] PGTABLE
[ 0.000000] BRK [0x02210000, 0x02210fff] PGTABLE
[ 0.000000] BRK [0x02211000, 0x02211fff] PGTABLE
[ 0.000000] BRK [0x02212000, 0x02212fff] PGTABLE
[ 0.000000] BRK [0x02213000, 0x02213fff] PGTABLE
[ 0.000000] RAMDISK: [mem 0x331f4000-0x358f1fff]
[ 0.000000] ACPI: Early table checksum verification disabled
[ 0.000000] ACPI: RSDP 0x00000000000FE020 000014 (v00 INTEL )
[ 0.000000] ACPI: RSDT 0x00000000CF6FD038 00004C (v01 INTEL DG965SS 00000697 01000013)
[ 0.000000] ACPI: FACP 0x00000000CF6FC000 000074 (v01 INTEL DG965SS 00000697 MSFT 01000013)
[ 0.000000] ACPI: DSDT 0x00000000CF6F7000 0040ED (v01 INTEL DG965SS 00000697 MSFT 01000013)
[ 0.000000] ACPI: FACS 0x00000000CF6A0000 000040
[ 0.000000] ACPI: APIC 0x00000000CF6F6000 000078 (v01 INTEL DG965SS 00000697 MSFT 01000013)
[ 0.000000] ACPI: WDDT 0x00000000CF6F5000 000040 (v01 INTEL DG965SS 00000697 MSFT 01000013)
[ 0.000000] ACPI: MCFG 0x00000000CF6F4000 00003C (v01 INTEL DG965SS 00000697 MSFT 01000013)
[ 0.000000] ACPI: ASF! 0x00000000CF6F3000 0000A6 (v32 INTEL DG965SS 00000697 MSFT 01000013)
[ 0.000000] ACPI: SSDT 0x00000000CF6F1000 0001BC (v01 INTEL CpuPm 00000697 MSFT 01000013)
[ 0.000000] ACPI: SSDT 0x00000000CF6F0000 000175 (v01 INTEL Cpu0Ist 00000697 MSFT 01000013)
[ 0.000000] ACPI: SSDT 0x00000000CF6EF000 000175 (v01 INTEL Cpu1Ist 00000697 MSFT 01000013)
[ 0.000000] ACPI: SSDT 0x00000000CF6EE000 000175 (v01 INTEL Cpu2Ist 00000697 MSFT 01000013)
[ 0.000000] ACPI: SSDT 0x00000000CF6ED000 000175 (v01 INTEL Cpu3Ist 00000697 MSFT 01000013)
[ 0.000000] ACPI: Local APIC address 0xfee00000
[ 0.000000] No NUMA configuration found
[ 0.000000] Faking a node at [mem 0x0000000000000000-0x00000000cf6fffff]
[ 0.000000] NODE_DATA(0) allocated [mem 0xcf617000-0xcf61bfff]
[ 0.000000] Zone ranges:
[ 0.000000] DMA [mem 0x0000000000001000-0x0000000000ffffff]
[ 0.000000] DMA32 [mem 0x0000000001000000-0x00000000cf6fffff]
[ 0.000000] Normal empty
[ 0.000000] Device empty
[ 0.000000] Movable zone start for each node
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000000001000-0x000000000008efff]
[ 0.000000] node 0: [mem 0x0000000000100000-0x00000000cf560fff]
[ 0.000000] node 0: [mem 0x00000000cf56e000-0x00000000cf61bfff]
[ 0.000000] node 0: [mem 0x00000000cf6e9000-0x00000000cf6ecfff]
[ 0.000000] node 0: [mem 0x00000000cf6f2000-0x00000000cf6f2fff]
[ 0.000000] node 0: [mem 0x00000000cf6ff000-0x00000000cf6fffff]
[ 0.000000] Initmem setup node 0 [mem 0x0000000000001000-0x00000000cf6fffff]
[ 0.000000] On node 0 totalpages: 849315
[ 0.000000] DMA zone: 64 pages used for memmap
[ 0.000000] DMA zone: 22 pages reserved
[ 0.000000] DMA zone: 3982 pages, LIFO batch:0
[ 0.000000] DMA32 zone: 13212 pages used for memmap
[ 0.000000] DMA32 zone: 845333 pages, LIFO batch:31
[ 0.000000] Reserving Intel graphics stolen memory at 0xcf800000-0xcfffffff
[ 0.000000] ACPI: PM-Timer IO Port: 0x408
[ 0.000000] ACPI: Local APIC address 0xfee00000
[ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x01] dfl dfl lint[0x1])
[ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x02] dfl dfl lint[0x1])
[ 0.000000] IOAPIC[0]: apic_id 2, version 32, address 0xfec00000, GSI 0-23
[ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 0 global_irq 2 dfl dfl)
[ 0.000000] ACPI: INT_SRC_OVR (bus 0 bus_irq 9 global_irq 9 high level)
[ 0.000000] ACPI: IRQ0 used by override.
[ 0.000000] ACPI: IRQ9 used by override.
[ 0.000000] Using ACPI (MADT) for SMP configuration information
[ 0.000000] smpboot: Allowing 4 CPUs, 2 hotplug CPUs
[ 0.000000] PM: Registered nosave memory: [mem 0x00000000-0x00000fff]
[ 0.000000] PM: Registered nosave memory: [mem 0x0008f000-0x0009ffff]
[ 0.000000] PM: Registered nosave memory: [mem 0x000a0000-0x000dffff]
[ 0.000000] PM: Registered nosave memory: [mem 0x000e0000-0x000fffff]
[ 0.000000] PM: Registered nosave memory: [mem 0xcf561000-0xcf56dfff]
[ 0.000000] PM: Registered nosave memory: [mem 0xcf61c000-0xcf6e8fff]
[ 0.000000] PM: Registered nosave memory: [mem 0xcf6ed000-0xcf6f1fff]
[ 0.000000] PM: Registered nosave memory: [mem 0xcf6f3000-0xcf6fefff]
[ 0.000000] e820: [mem 0xd0000000-0xffefffff] available for PCI devices
[ 0.000000] Booting paravirtualized kernel on bare hardware
[ 0.000000] clocksource: refined-jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645519600211568 ns
[ 0.000000] setup_percpu: NR_CPUS:512 nr_cpumask_bits:512 nr_cpu_ids:4 nr_node_ids:1
[ 0.000000] PERCPU: Embedded 34 pages/cpu @ffff8800cf000000 s99480 r8192 d31592 u524288
[ 0.000000] pcpu-alloc: s99480 r8192 d31592 u524288 alloc=1*2097152
[ 0.000000] pcpu-alloc: [0] 0 1 2 3
[ 0.000000] Built 1 zonelists in Node order, mobility grouping on. Total pages: 836017
[ 0.000000] Policy zone: DMA32
[ 0.000000] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-4.4.0-151-generic root=UUID=29f49899-a2fa-496f-99e8-0d40b69303df ro quiet splash vt.handoff=7
[ 0.000000] PID hash table entries: 4096 (order: 3, 32768 bytes)
[ 0.000000] Calgary: detecting Calgary via BIOS EBDA area
[ 0.000000] Calgary: Unable to locate Rio Grande table in EBDA - bailing!
[ 0.000000] Memory: 3284664K/3397260K available (8613K kernel code, 1335K rwdata, 4028K rodata, 1484K init, 1284K bss, 112596K reserved, 0K cma-reserved)
[ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[ 0.000000] Kernel/User page tables isolation: enabled
[ 0.000000] Hierarchical RCU implementation.
[ 0.000000] Build-time adjustment of leaf fanout to 64.
[ 0.000000] RCU restricting CPUs from NR_CPUS=512 to nr_cpu_ids=4.
[ 0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=64, nr_cpu_ids=4
[ 0.000000] NR_IRQS:33024 nr_irqs:456 16
[ 0.000000] vt handoff: transparent VT on vt#7
[ 0.000000] Console: colour dummy device 80x25
[ 0.000000] console [tty0] enabled
[ 0.000000] tsc: Fast TSC calibration using PIT
[ 0.000000] tsc: Detected 2131.186 MHz processor
[ 0.008013] Calibrating delay loop (skipped), value calculated using timer frequency.. 4262.37 BogoMIPS (lpj=8524744)
[ 0.008017] pid_max: default: 32768 minimum: 301
[ 0.008025] ACPI: Core revision 20150930
[ 0.015955] ACPI: 6 ACPI AML tables successfully acquired and loaded
[ 0.015986] Security Framework initialized
[ 0.015989] Yama: becoming mindful.
[ 0.016023] AppArmor: AppArmor initialized
[ 0.016462] Dentry cache hash table entries: 524288 (order: 10, 4194304 bytes)
[ 0.018455] Inode-cache hash table entries: 262144 (order: 9, 2097152 bytes)
[ 0.019476] Mount-cache hash table entries: 8192 (order: 4, 65536 bytes)
[ 0.019485] Mountpoint-cache hash table entries: 8192 (order: 4, 65536 bytes)
[ 0.019870] Initializing cgroup subsys io
[ 0.019879] Initializing cgroup subsys memory
[ 0.019893] Initializing cgroup subsys devices
[ 0.019898] Initializing cgroup subsys freezer
[ 0.019903] Initializing cgroup subsys net_cls
[ 0.019907] Initializing cgroup subsys perf_event
[ 0.019911] Initializing cgroup subsys net_prio
[ 0.019916] Initializing cgroup subsys hugetlb
[ 0.019919] Initializing cgroup subsys pids
[ 0.019947] mce: CPU supports 6 MCE banks
[ 0.019957] CPU0: Thermal monitoring enabled (TM2)
[ 0.019962] process: using mwait in idle threads
[ 0.019969] Last level iTLB entries: 4KB 128, 2MB 4, 4MB 4
[ 0.019971] Last level dTLB entries: 4KB 256, 2MB 0, 4MB 32, 1GB 0
[ 0.019975] Spectre V2 : Mitigation: Full generic retpoline
[ 0.019976] Spectre V2 : Spectre v2 / SpectreRSB mitigation: Filling RSB on context switch
[ 0.019978] Speculative Store Bypass: Vulnerable
[ 0.020036] MDS: Vulnerable: Clear CPU buffers attempted, no microcode
[ 0.020531] Freeing SMP alternatives memory: 36K
[ 0.023718] ftrace: allocating 32299 entries in 127 pages
[ 0.052148] smpboot: APIC(0) Converting physical 0 to logical package 0
[ 0.052152] smpboot: Max logical packages: 2
[ 0.052533] ..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
[ 0.096000] smpboot: CPU0: Intel(R) Core(TM)2 CPU 6400 @ 2.13GHz (family: 0x6, model: 0xf, stepping: 0x6)
[ 0.096000] Performance Events: PEBS fmt0-, 4-deep LBR, Core2 events, Intel PMU driver.
[ 0.096000] core: PEBS disabled due to CPU errata
[ 0.096000] ... version: 2
[ 0.096000] ... bit width: 40
[ 0.096000] ... generic registers: 2
[ 0.096000] ... value mask: 000000ffffffffff
[ 0.096000] ... max period: 000000007fffffff
[ 0.096000] ... fixed-purpose events: 3
[ 0.096000] ... event mask: 0000000700000003
[ 0.096000] NMI watchdog: enabled on all CPUs, permanently consumes one hw-PMU counter.
[ 0.096000] x86: Booting SMP configuration:
[ 0.096000] .... node #0, CPUs: #1
[ 0.012000] microcode: CPU1 microcode updated early to revision 0xd0, date = 2010-09-30
[ 0.096046] x86: Booted up 1 node, 2 CPUs
[ 0.096052] smpboot: Total of 2 processors activated (8524.74 BogoMIPS)
[ 0.097307] devtmpfs: initialized
[ 0.101671] evm: security.selinux
[ 0.101674] evm: security.SMACK64
[ 0.101675] evm: security.SMACK64EXEC
[ 0.101677] evm: security.SMACK64TRANSMUTE
[ 0.101679] evm: security.SMACK64MMAP
[ 0.101680] evm: security.ima
[ 0.101682] evm: security.capability
[ 0.101764] PM: Registering ACPI NVS region [mem 0xcf61c000-0xcf6e8fff] (839680 bytes)
[ 0.101876] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns
[ 0.101890] futex hash table entries: 1024 (order: 4, 65536 bytes)
[ 0.101959] pinctrl core: initialized pinctrl subsystem
[ 0.101959] RTC time: 16:16:52, date: 06/29/19
[ 0.101959] NET: Registered protocol family 16
[ 0.112008] cpuidle: using governor ladder
[ 0.120006] cpuidle: using governor menu
[ 0.120012] PCCT header not found.
[ 0.120099] ACPI: bus type PCI registered
[ 0.120103] acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5
[ 0.120225] PCI: MMCONFIG for domain 0000 [bus 00-7f] at [mem 0xf0000000-0xf7ffffff] (base 0xf0000000)
[ 0.120230] PCI: not using MMCONFIG
[ 0.120232] PCI: Using configuration type 1 for base access
[ 0.128127] ACPI: Added _OSI(Module Device)
[ 0.128130] ACPI: Added _OSI(Processor Device)
[ 0.128132] ACPI: Added _OSI(3.0 _SCP Extensions)
[ 0.128135] ACPI: Added _OSI(Processor Aggregator Device)
[ 0.130832] ACPI: Interpreter enabled
[ 0.130851] ACPI: (supports S0 S3 S4 S5)
[ 0.130853] ACPI: Using IOAPIC for interrupt routing
[ 0.130879] PCI: MMCONFIG for domain 0000 [bus 00-7f] at [mem 0xf0000000-0xf7ffffff] (base 0xf0000000)
[ 0.131023] PCI: MMCONFIG at [mem 0xf0000000-0xf7ffffff] reserved in ACPI motherboard resources
[ 0.131035] PCI: Using host bridge windows from ACPI; if necessary, use "pci=nocrs" and report a bug
[ 0.137595] ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff])
[ 0.137603] acpi PNP0A03:00: _OSC: OS supports [ExtendedConfig ASPM ClockPM Segments MSI]
[ 0.137609] acpi PNP0A03:00: _OSC failed (AE_NOT_FOUND); disabling ASPM
[ 0.137619] acpi PNP0A03:00: [Firmware Info]: MMCONFIG for domain 0000 [bus 00-7f] only partially covers this bridge
[ 0.138444] PCI host bridge to bus 0000:00
[ 0.138449] pci_bus 0000:00: root bus resource [io 0x0000-0x0cf7 window]
****Terminated by maximum allowed size in entry****
我多次更换内存模块，尝试了不同类型的内存条，但结果总是一样。我无法弄清楚是什么限制了 Linux 看到的内存，尽管硬件中安装了内存。我遗漏了什么？
提前致谢。