我不明白为什么我的 Ubuntu 18.04 报告 11.8Gb 而不是预期的 +/-32Gb。
我在戴尔笔记本电脑 Precision 7510 上各有 2 个 16Gb RAM 的物理“块”。
操作系统是64位：
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.1 LTS
Release: 18.04
Codename: bionic
Ubuntu 报告 11.8Gb，命令htop报告最大 RAM 为 11.8Gb。
我们在工作中做了一些测试：
- 我们更新了BIOS 从 Dell v1.16.3 升级到最新版本。没有改变。
- 使用另一台同事笔记本电脑的其他 2x8Gb RAM，操作系统仍然报告 11.8Gb。没有改变
- 只用我的一块 16Gb（每次测试我的两个记忆片段）操作系统报告...16Gb! 比如只有当内存中有 2 块 RAM（2x16 或 2x8）时才会出现问题
- 我们在可启动的 Linux USB 密钥（同事的 USB 密钥，这不是 Ubuntu，我没有问他的操作系统）上启动，并且这个备用 Linux 操作系统检测到了 32Gb！
- 编辑 2019/01/27：我在带有 Live Ubuntu 18.04 的可启动 USB 密钥上启动，结果相同，vanilla Ubuntu 18.04 报告 11.8Go。
在此问题，关于内存的一行引用/var/log/kern.log可能表明一些内存是为视频保留的。
在我的电脑里/var/log/kern.log，这行字有时表示大约 12Gb，有时表示 16Gb：
Jan 24 11:06:29 proust kernel: [ 0.000000] Memory: 12027524K/12374028K available (12300K kernel code, 2472K rwdata, 4252K rodata, 2408K init, 2416K bss, 346504K reserved, 0K cma-reserved)
...
Jan 25 16:01:55 proust kernel: [ 0.000000] Memory: 16182536K/16592532K available (12300K kernel code, 2472K rwdata, 4252K rodata, 2408K init, 2416K bss, 409996K reserved, 0K cma-reserved)
可用的 12027524K 是否与操作系统报告的 11.8Gb 相对应？
即，如果我在显示 16182536K 时截取屏幕截图，那么操作系统会报告可用空间为 16Gb 而不是 11.8 吗？
其中一些摘录/var/log/kern.log可能有用，也可能无用。
Jan 22 10:28:11 proust kernel: [ 7.518122] Adding 33192956k swap on /dev/nvme0n1p5. Priority:-2 extents:1 across:33192956k SSFS
[...]
Jan 22 10:28:11 proust kernel: [ 1.655250] [drm] Detected VRAM RAM=2048M, BAR=256M
Jan 22 10:28:11 proust kernel: [ 1.655250] [drm] RAM width 128bits DDR
Jan 22 10:28:11 proust kernel: [ 1.655422] [TTM] Zone kernel: Available graphics memory: 6044034 kiB
Jan 22 10:28:11 proust kernel: [ 1.655423] [TTM] Zone dma32: Available graphics memory: 2097152 kiB
Jan 22 10:28:11 proust kernel: [ 1.655423] [TTM] Initializing pool allocator
Jan 22 10:28:11 proust kernel: [ 1.655444] [TTM] Initializing DMA pool allocator
Jan 22 10:28:11 proust kernel: [ 1.655454] [drm] radeon: 2048M of VRAM memory ready
Jan 22 10:28:11 proust kernel: [ 1.655454] [drm] radeon: 2048M of GTT memory ready.
[...]
Jan 22 10:28:11 proust kernel: [ 1.844114] [drm] Memory usable by graphics device = 4096M
还有一些错误（我从未检查过这个/var/log/kern.log文件）
Jan 22 10:28:11 proust kernel: [ 5.573929] EXT4-fs (nvme0n1p1): re-mounted. Opts: errors=remount-ro
...
Jan 22 10:28:11 proust kernel: [ 6.040729] thermal thermal_zone10: failed to read out thermal zone (-61)
...
Jan 22 10:28:11 proust kernel: [ 10.690615] vboxdrv: module verification failed: signature and/or required key missing - tainting kernel
...
Jan 22 10:28:16 proust kernel: [ 15.304753] ACPI Error: [SPRT] Namespace lookup failure, AE_ALREADY_EXISTS (20170831/dswload2-346)
...
Jan 22 10:28:16 proust kernel: [ 15.304764] ACPI Error: Method parse/execution failed \_GPE._E42, AE_ALREADY_EXISTS (20170831/psparse-550)
...
Jan 22 10:28:21 proust kernel: [ 20.552778] xhci_hcd 0000:3c:00.0: Host halt failed, -19
Jan 22 10:28:21 proust kernel: [ 20.552780] xhci_hcd 0000:3c:00.0: Host not accessible, reset failed.
...
Jan 22 10:30:10 proust kernel: [ 129.221450] radeon 0000:01:00.0: failed VCE resume (-22).
...
Jan 22 10:30:11 proust kernel: [ 130.876028] [drm:uvd_v1_0_ib_test [radeon]] *ERROR* radeon: fence wait timed out.
Jan 22 10:30:11 proust kernel: [ 130.876086] [drm:radeon_ib_ring_tests [radeon]] *ERROR* radeon: failed testing IB on ring 5 (-110).
Jan 22 10:30:11 proust kernel: [ 130.876107] radeon 0000:01:00.0: scheduling IB failed (-12).
Jan 22 10:30:11 proust kernel: [ 130.876149] [drm:radeon_vce_get_create_msg [radeon]] *ERROR* radeon: failed to schedule ib (-12).
Jan 22 10:30:11 proust kernel: [ 130.876190] [drm:radeon_vce_ib_test [radeon]] *ERROR* radeon: failed to get create msg (-12).
Jan 22 10:30:11 proust kernel: [ 130.876230] [drm:radeon_ib_ring_tests [radeon]] *ERROR* radeon: failed testing IB on ring 6 (-12).
Jan 22 10:30:11 proust kernel: [ 130.876245] radeon 0000:01:00.0: scheduling IB failed (-12).
Jan 22 10:30:11 proust kernel: [ 130.876282] [drm:radeon_vce_get_create_msg [radeon]] *ERROR* radeon: failed to schedule ib (-12).
Jan 22 10:30:11 proust kernel: [ 130.876318] [drm:radeon_vce_ib_test [radeon]] *ERROR* radeon: failed to get create msg (-12).
Jan 22 10:30:11 proust kernel: [ 130.876355] [drm:radeon_ib_ring_tests [radeon]] *ERROR* radeon: failed testing IB on ring 7 (-12).
...
Jan 22 10:30:22 proust kernel: [ 141.892295] ACPI Error: [SPRT] Namespace lookup failure, AE_ALREADY_EXISTS (20170831/dswload2-346)
我还看到很多非错误行：
Jan 22 18:42:28 proust kernel: [29667.466039] [drm] Reducing the compressed framebuffer size. This may lead to less power savings than a non-reduced-size. Try to increase stolen memory size if available in BIOS.
以下是在其他线程上发现的一些命令：
$ cat /proc/meminfo
MemTotal: 12324368 kB
MemFree: 267520 kB
MemAvailable: 5806556 kB
Buffers: 1055348 kB
Cached: 5303968 kB
SwapCached: 0 kB
Active: 6774156 kB
Inactive: 4251464 kB
Active(anon): 4678200 kB
Inactive(anon): 1035304 kB
Active(file): 2095956 kB
Inactive(file): 3216160 kB
Unevictable: 112 kB
Mlocked: 112 kB
SwapTotal: 33192956 kB
SwapFree: 33192956 kB
Dirty: 4360 kB
Writeback: 0 kB
AnonPages: 4666392 kB
Mapped: 912788 kB
Shmem: 1047204 kB
Slab: 724556 kB
SReclaimable: 554796 kB
SUnreclaim: 169760 kB
KernelStack: 22000 kB
PageTables: 105136 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 39355140 kB
Committed_AS: 18975512 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 0 kB
VmallocChunk: 0 kB
HardwareCorrupted: 0 kB
AnonHugePages: 0 kB
ShmemHugePages: 0 kB
ShmemPmdMapped: 0 kB
CmaTotal: 0 kB
CmaFree: 0 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
DirectMap4k: 466080 kB
DirectMap2M: 12146688 kB
DirectMap1G: 1048576 kB
$ free
total used free shared buff/cache available
Mem: 12324368 5342192 1503780 1142692 5478396 5511600
Swap: 33192956 0 33192956
最后，命令的结果dmidecode（我发现这里）看起来它看到了所有的 RAM（2 个内存设备，每个 16384 MB：Handle 0x0049和Handle 0x004B2 个可用/空插槽Handle 0x004A和Handle 0x004BC）：
$ sudo dmidecode
[...]
Handle 0x0048, DMI type 16, 23 bytes
Physical Memory Array
Location: System Board Or Motherboard
Use: System Memory
Error Correction Type: None
Maximum Capacity: 64 GB
Error Information Handle: Not Provided
Number Of Devices: 4
Handle 0x0049, DMI type 17, 40 bytes
Memory Device
Array Handle: 0x0048
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 16384 MB
Form Factor: SODIMM
Set: None
Locator: ChannelA-DIMM0
Bank Locator: BANK 0
Type: DDR4
Type Detail: Synchronous
Speed: 2133 MT/s
Manufacturer: Micron
Serial Number: 12161215
Asset Tag: 2C0C0000
Part Number: 16ATF2G64HZ-2G1A1
Rank: 2
Configured Clock Speed: 2133 MT/s
Minimum Voltage: Unknown
Maximum Voltage: Unknown
Configured Voltage: 1.2 V
Handle 0x004A, DMI type 17, 40 bytes
Memory Device
Array Handle: 0x0048
Error Information Handle: Not Provided
Total Width: Unknown
Data Width: Unknown
Size: No Module Installed
Form Factor: DIMM
Set: None
Locator: ChannelB-DIMM0
Bank Locator: BANK 1
Type: Unknown
Type Detail: None
Speed: Unknown
Manufacturer: Not Specified
Serial Number: Not Specified
Asset Tag: Not Specified
Part Number: Not Specified
Rank: Unknown
Configured Clock Speed: Unknown
Minimum Voltage: Unknown
Maximum Voltage: Unknown
Configured Voltage: Unknown
Handle 0x004B, DMI type 17, 40 bytes
Memory Device
Array Handle: 0x0048
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 16384 MB
Form Factor: SODIMM
Set: None
Locator: ChannelB-DIMM1
Bank Locator: BANK 2
Type: DDR4
Type Detail: Synchronous
Speed: 2133 MT/s
Manufacturer: Micron
Serial Number: 12121212
Asset Tag: 00000000
Part Number: 16ATF2G64HZ-2G1A1
Rank: 2
Configured Clock Speed: 2133 MT/s
Minimum Voltage: Unknown
Maximum Voltage: Unknown
Configured Voltage: 1.2 V
Handle 0x004C, DMI type 17, 40 bytes
Memory Device
Array Handle: 0x0048
Error Information Handle: Not Provided
Total Width: Unknown
Data Width: Unknown
Size: No Module Installed
Form Factor: DIMM
Set: None
Locator: ChannelA-DIMM1
Bank Locator: BANK 3
Type: Unknown
Type Detail: None
Speed: Unknown
Manufacturer: Not Specified
Serial Number: Not Specified
Asset Tag: Not Specified
Part Number: Not Specified
Rank: Unknown
Configured Clock Speed: Unknown
Minimum Voltage: Unknown
Maximum Voltage: Unknown
Configured Voltage: Unknown
Handle 0x004D, DMI type 19, 31 bytes
Memory Array Mapped Address
Starting Address: 0x00000000000
Ending Address: 0x007FFFFFFFF
Range Size: 32 GB
Physical Array Handle: 0x0048
Partition Width: 2
欢迎提供任何线索、对我的案例的解释或可供验证的信息。
编辑 2019-01-28
memtest86（默认测试，耗时约 7.5 小时）结果
报告48 项测试中，有 25 项 (52%) 未通过。
这些错误是否会导致 Ubuntu 不显示 28/32Gb 可用空间，但其他发行版如 Fedora 却显示？
编辑 2019-02-03
我从 USB 密钥启动了 Live Fedora 29。
结果看起来一样，只有 12Gb 可用于操作系统：
htopFedora 上的结果
Fedora 操作系统详细信息窗口
的结果dmesg | grep Memory：
[liveuser@localhost-live ~]$ dmesg | grep Memory
[ 0.000000] Memory: 12264216K/12607208K available (12300K kernel code, 1624K rwdata, 4056K rodata, 2160K init, 1336K bss, 342992K reserved, 0K cma-reserved)
[ 0.024277] x86/mm: Memory block size: 128MB
[ 3.774268] usb 1-1: Product: USB Flash Memory
[ 6.433239] scsi 5:0:0:0: Direct-Access USB Flash Memory 5.00 PQ: 0 ANSI: 0 CCS
我还在 Fedora 上添加了整个dmesg启动，直到这个“memory”行。
是块/部分BIOS 提供的物理 RAM 映射普通的？
[liveuser@localhost-live ~]$ dmesg
[ 0.000000] Linux version 4.18.16-300.fc29.x86_64 ([email protected]) (gcc version 8.2.1 20180801 (Red Hat 8.2.1-2) (GCC)) #1 SMP Sat Oct 20 23:24:08 UTC 2018
[ 0.000000] Command line: BOOT_IMAGE=vmlinuz initrd=initrd.img root=live:CDLABEL=Fedora-WS-Live-29-1-2 rd.live.image rd.live.check quiet
[ 0.000000] x86/fpu: Supporting XSAVE feature 0x001: 'x87 floating point registers'
[ 0.000000] x86/fpu: Supporting XSAVE feature 0x002: 'SSE registers'
[ 0.000000] x86/fpu: Supporting XSAVE feature 0x004: 'AVX registers'
[ 0.000000] x86/fpu: Supporting XSAVE feature 0x008: 'MPX bounds registers'
[ 0.000000] x86/fpu: Supporting XSAVE feature 0x010: 'MPX CSR'
[ 0.000000] x86/fpu: xstate_offset[2]: 576, xstate_sizes[2]: 256
[ 0.000000] x86/fpu: xstate_offset[3]: 832, xstate_sizes[3]: 64
[ 0.000000] x86/fpu: xstate_offset[4]: 896, xstate_sizes[4]: 64
[ 0.000000] x86/fpu: Enabled xstate features 0x1f, context size is 960 bytes, using 'compacted' format.
[ 0.000000] BIOS-provided physical RAM map:
[ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009dbff] usable
[ 0.000000] BIOS-e820: [mem 0x000000000009dc00-0x000000000009ffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved
[ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x0000000066540fff] usable
[ 0.000000] BIOS-e820: [mem 0x0000000066541000-0x0000000066541fff] ACPI NVS
[ 0.000000] BIOS-e820: [mem 0x0000000066542000-0x000000006b7a2fff] reserved
[ 0.000000] BIOS-e820: [mem 0x000000006b7a3000-0x000000006b7dffff] ACPI data
[ 0.000000] BIOS-e820: [mem 0x000000006b7e0000-0x000000006be59fff] ACPI NVS
[ 0.000000] BIOS-e820: [mem 0x000000006be5a000-0x000000006fffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000e0000000-0x00000000efffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000fe000000-0x00000000fe010fff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000fec00000-0x00000000fec00fff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000fee00000-0x00000000fee00fff] reserved
[ 0.000000] BIOS-e820: [mem 0x00000000ff000000-0x00000000ffffffff] reserved
[ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000039b2dcfff] usable
[ 0.000000] BIOS-e820: [mem 0x000000039b2dd000-0x000000088dffffff] reserved
[ 0.000000] NX (Execute Disable) protection: active
[ 0.000000] SMBIOS 3.0.0 present.
[ 0.000000] DMI: Dell Inc. Precision 7510/0M1YNP, BIOS 1.16.3 09/12/2018
[ 0.000000] e820: update [mem 0x00000000-0x00000fff] usable ==> reserved
[ 0.000000] e820: remove [mem 0x000a0000-0x000fffff] usable
[ 0.000000] last_pfn = 0x39b2dd max_arch_pfn = 0x400000000
[ 0.000000] MTRR default type: write-back
[ 0.000000] MTRR fixed ranges enabled:
[ 0.000000] 00000-9FFFF write-back
[ 0.000000] A0000-BFFFF uncachable
[ 0.000000] C0000-FFFFF write-protect
[ 0.000000] MTRR variable ranges enabled:
[ 0.000000] 0 base 0080000000 mask 7F80000000 uncachable
[ 0.000000] 1 base 0070000000 mask 7FF0000000 uncachable
[ 0.000000] 2 base 006E000000 mask 7FFE000000 uncachable
[ 0.000000] 3 base 006D800000 mask 7FFF800000 uncachable
[ 0.000000] 4 disabled
[ 0.000000] 5 disabled
[ 0.000000] 6 disabled
[ 0.000000] 7 disabled
[ 0.000000] 8 disabled
[ 0.000000] 9 disabled
[ 0.000000] x86/PAT: Configuration [0-7]: WB WC UC- UC WB WP UC- WT
[ 0.000000] last_pfn = 0x66541 max_arch_pfn = 0x400000000
[ 0.000000] found SMP MP-table at [mem 0x000fce40-0x000fce4f] mapped at [(____ptrval____)]
[ 0.000000] Base memory trampoline at [(____ptrval____)] 97000 size 24576
[ 0.000000] Using GB pages for direct mapping
[ 0.000000] BRK [0x348aaf000, 0x348aaffff] PGTABLE
[ 0.000000] BRK [0x348ab0000, 0x348ab0fff] PGTABLE
[ 0.000000] BRK [0x348ab1000, 0x348ab1fff] PGTABLE
[ 0.000000] BRK [0x348ab2000, 0x348ab2fff] PGTABLE
[ 0.000000] BRK [0x348ab3000, 0x348ab3fff] PGTABLE
[ 0.000000] BRK [0x348ab4000, 0x348ab4fff] PGTABLE
[ 0.000000] BRK [0x348ab5000, 0x348ab5fff] PGTABLE
[ 0.000000] BRK [0x348ab6000, 0x348ab6fff] PGTABLE
[ 0.000000] RAMDISK: [mem 0x63526000-0x66540fff]
[ 0.000000] ACPI: Early table checksum verification disabled
[ 0.000000] ACPI: RSDP 0x00000000000E98B0 000024 (v02 DELL )
[ 0.000000] ACPI: XSDT 0x000000006B7AF0B0 0000DC (v01 DELL CBX3 01072009 AMI 00010013)
[ 0.000000] ACPI: FACP 0x000000006B7D0780 00010C (v05 DELL CBX3 01072009 AMI 00010013)
[ 0.000000] ACPI: DSDT 0x000000006B7AF218 021568 (v02 DELL CBX3 01072009 INTL 20120913)
[ 0.000000] ACPI: FACS 0x000000006BE57E80 000040
[ 0.000000] ACPI: APIC 0x000000006B7D0890 0000BC (v03 DELL CBX3 01072009 AMI 00010013)
[ 0.000000] ACPI: FPDT 0x000000006B7D0950 000044 (v01 DELL CBX3 01072009 AMI 00010013)
[ 0.000000] ACPI: MCFG 0x000000006B7D0998 00003C (v01 DELL CBX3 01072009 MSFT 00000097)
[ 0.000000] ACPI: HPET 0x000000006B7D09D8 000038 (v01 DELL CBX3 01072009 AMI. 0005000B)
[ 0.000000] ACPI: SSDT 0x000000006B7D0A10 00046D (v01 SataRe SataTabl 00001000 INTL 20120913)
[ 0.000000] ACPI: LPIT 0x000000006B7D0E80 000094 (v01 INTEL SKL 00000000 MSFT 0000005F)
[ 0.000000] ACPI: SSDT 0x000000006B7D0F18 000248 (v02 INTEL sensrhub 00000000 INTL 20120913)
[ 0.000000] ACPI: SSDT 0x000000006B7D1160 002BAE (v02 INTEL PtidDevc 00001000 INTL 20120913)
[ 0.000000] ACPI: SSDT 0x000000006B7D3D10 0007D9 (v02 INTEL xh_rvp07 00000000 INTL 20120913)
[ 0.000000] ACPI: DBGP 0x000000006B7D44F0 000034 (v01 INTEL 00000000 MSFT 0000005F)
[ 0.000000] ACPI: DBG2 0x000000006B7D4528 000054 (v00 INTEL 00000000 MSFT 0000005F)
[ 0.000000] ACPI: SSDT 0x000000006B7D4580 003866 (v02 SaSsdt SaSsdt 00003000 INTL 20120913)
[ 0.000000] ACPI: UEFI 0x000000006B7D7DE8 000042 (v01 00000000 00000000)
[ 0.000000] ACPI: SSDT 0x000000006B7D7E30 000E73 (v02 CpuRef CpuSsdt 00003000 INTL 20120913)
[ 0.000000] ACPI: SSDT 0x000000006B7D8CA8 00435D (v02 DptfTa DptfTabl 00001000 INTL 20120913)
[ 0.000000] ACPI: MSDM 0x000000006B7DD008 000055 (v03 DELL CBX3 06222004 AMI 00010013)
[ 0.000000] ACPI: SLIC 0x000000006B7DD060 000176 (v03 DELL CBX3 01072009 MSFT 00010013)
[ 0.000000] ACPI: SSDT 0x000000006B7DD1D8 000094 (v02 SgRef SgPeg 00001000 INTL 20120913)
[ 0.000000] ACPI: DMAR 0x000000006B7DD270 0000A8 (v01 INTEL SKL 00000001 INTL 00000001)
[ 0.000000] ACPI: TPM2 0x000000006B7DD318 000034 (v03 Tpm2Tabl 00000001 AMI 00000000)
[ 0.000000] ACPI: SSDT 0x000000006B7DD350 000F00 (v01 AmdRef AmdTabl 00001000 INTL 20120913)
[ 0.000000] ACPI: ASF! 0x000000006B7DE250 0000A5 (v32 INTEL HCG 00000001 TFSM 000F4240)
[ 0.000000] ACPI: Local APIC address 0xfee00000
[ 0.000000] No NUMA configuration found
[ 0.000000] Faking a node at [mem 0x0000000000000000-0x000000039b2dcfff]
[ 0.000000] NODE_DATA(0) allocated [mem 0x39b2b2000-0x39b2dcfff]
[ 0.000000] Zone ranges:
[ 0.000000] DMA [mem 0x0000000000001000-0x0000000000ffffff]
[ 0.000000] DMA32 [mem 0x0000000001000000-0x00000000ffffffff]
[ 0.000000] Normal [mem 0x0000000100000000-0x000000039b2dcfff]
[ 0.000000] Device empty
[ 0.000000] Movable zone start for each node
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000000001000-0x000000000009cfff]
[ 0.000000] node 0: [mem 0x0000000000100000-0x0000000066540fff]
[ 0.000000] node 0: [mem 0x0000000100000000-0x000000039b2dcfff]
[ 0.000000] Reserved but unavailable: 26694 pages
[ 0.000000] Initmem setup node 0 [mem 0x0000000000001000-0x000000039b2dcfff]
[ 0.000000] On node 0 totalpages: 3151802
[ 0.000000] DMA zone: 64 pages used for memmap
[ 0.000000] DMA zone: 21 pages reserved
[ 0.000000] DMA zone: 3996 pages, LIFO batch:0
[ 0.000000] DMA32 zone: 6486 pages used for memmap
[ 0.000000] DMA32 zone: 415041 pages, LIFO batch:31
[ 0.000000] Normal zone: 42700 pages used for memmap
[ 0.000000] Normal zone: 2732765 pages, LIFO batch:31
[ 0.000000] Reserving Intel graphics memory at [mem 0x6e000000-0x6fffffff]
[ 0.000000] ACPI: PM-Timer IO Port: 0x1808
[ 0.000000] ACPI: Local APIC address 0xfee00000
[ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x01] high edge lint[0x1])
[ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x02] high edge lint[0x1])
[ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x03] high edge lint[0x1])
[ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x04] high edge lint[0x1])
[ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x05] high edge lint[0x1])
[ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x06] high edge lint[0x1])
[ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x07] high edge lint[0x1])
[ 0.000000] ACPI: LAPIC_NMI (acpi_id[0x08] high edge lint[0x1])
[ 0.000000] IOAPIC[0]: apic_id 2, version 32, address 0xfec00000, GSI 0-119
[ 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] ACPI: HPET id: 0x8086a701 base: 0xfed00000
[ 0.000000] smpboot: Allowing 8 CPUs, 0 hotplug CPUs
[ 0.000000] PM: Registered nosave memory: [mem 0x00000000-0x00000fff]
[ 0.000000] PM: Registered nosave memory: [mem 0x0009d000-0x0009dfff]
[ 0.000000] PM: Registered nosave memory: [mem 0x0009e000-0x0009ffff]
[ 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 0x66541000-0x66541fff]
[ 0.000000] PM: Registered nosave memory: [mem 0x66542000-0x6b7a2fff]
[ 0.000000] PM: Registered nosave memory: [mem 0x6b7a3000-0x6b7dffff]
[ 0.000000] PM: Registered nosave memory: [mem 0x6b7e0000-0x6be59fff]
[ 0.000000] PM: Registered nosave memory: [mem 0x6be5a000-0x6fffffff]
[ 0.000000] PM: Registered nosave memory: [mem 0x70000000-0xdfffffff]
[ 0.000000] PM: Registered nosave memory: [mem 0xe0000000-0xefffffff]
[ 0.000000] PM: Registered nosave memory: [mem 0xf0000000-0xfdffffff]
[ 0.000000] PM: Registered nosave memory: [mem 0xfe000000-0xfe010fff]
[ 0.000000] PM: Registered nosave memory: [mem 0xfe011000-0xfebfffff]
[ 0.000000] PM: Registered nosave memory: [mem 0xfec00000-0xfec00fff]
[ 0.000000] PM: Registered nosave memory: [mem 0xfec01000-0xfedfffff]
[ 0.000000] PM: Registered nosave memory: [mem 0xfee00000-0xfee00fff]
[ 0.000000] PM: Registered nosave memory: [mem 0xfee01000-0xfeffffff]
[ 0.000000] PM: Registered nosave memory: [mem 0xff000000-0xffffffff]
[ 0.000000] [mem 0x70000000-0xdfffffff] 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: 1910969940391419 ns
[ 0.000000] random: get_random_bytes called from start_kernel+0x93/0x558 with crng_init=0
[ 0.000000] setup_percpu: NR_CPUS:1024 nr_cpumask_bits:8 nr_cpu_ids:8 nr_node_ids:1
[ 0.000000] percpu: Embedded 45 pages/cpu @(____ptrval____) s147456 r8192 d28672 u262144
[ 0.000000] pcpu-alloc: s147456 r8192 d28672 u262144 alloc=1*2097152
[ 0.000000] pcpu-alloc: [0] 0 1 2 3 4 5 6 7
[ 0.000000] Built 1 zonelists, mobility grouping on. Total pages: 3102531
[ 0.000000] Policy zone: Normal
[ 0.000000] Kernel command line: BOOT_IMAGE=vmlinuz initrd=initrd.img root=live:CDLABEL=Fedora-WS-Live-29-1-2 rd.live.image rd.live.check quiet
[ 0.000000] Memory: 12264216K/12607208K available (12300K kernel code, 1624K rwdata, 4056K rodata, 2160K init, 1336K bss, 342992K reserved, 0K cma-reserved)
[ 0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=8, Nodes=1
答案1
更换物理内存条后（用 4 个 8Go 替换 2 个旧的 16Go），现在检测到 31.2 Go。
因此，这是物理内存问题。
此外，还有htop：
