![“free”输出中的总RAM小于实际RAM大小](https://linux22.com/image/1203964/%E2%80%9Cfree%E2%80%9D%E8%BE%93%E5%87%BA%E4%B8%AD%E7%9A%84%E6%80%BBRAM%E5%B0%8F%E4%BA%8E%E5%AE%9E%E9%99%85RAM%E5%A4%A7%E5%B0%8F.png)
我在一台拥有 4 GB RAM 的 Lenovo X1 Carbon 3460-4T9 计算机上运行 Ubuntu 16.04.3 LTS x86_64。但是,free 命令仅显示总共 2610 MB:
vmalep@X1:~$ free -m
total used free shared buff/cache available
Mem: 2610 1525 108 243 976 649
sudo lshw -c memory 命令显示所有内存:
*-memory
description: System Memory
physical id: 7
slot: System board or motherboard
size: 4GiB
*-bank:0
description: Chip DDR3 Synchronous 1333 MHz (0,8 ns)
product: HMT42556MFR6A-G7
vendor: Hynix/Hyundai
physical id: 0
serial: None
slot: ChannelA
size: 2GiB
width: 64 bits
clock: 1333MHz (0.8ns)
*-bank:1
description: Chip DDR3 Synchronous 1333 MHz (0,8 ns)
product: HMT42556MFR6A-G7
vendor: Hynix/Hyundai
physical id: 1
serial: None
slot: ChannelB
size: 2GiB
width: 64 bits
clock: 1333MHz (0.8ns)
dmesg 的输出:
vmalep@X1:~$ dmesg | grep Memory
[ 0.000000] Memory: 2620420K/2807280K available (12300K kernel code, 2481K rwdata, 4004K rodata, 2364K init, 2368K bss, 186860K reserved, 0K cma-reserved)
[ 0.092487] x86/mm: Memory block size: 128MB
[ 2.791622] [drm] Memory usable by graphics device = 2048M
正在使用的内核:
vmalep@X1:~$ uname -r
4.13.0-32-generic
另外,如果使用实时 USB(相同的 Ubuntu 16.04.3 LTS 版本)启动,则 4Gb 的 RAM 正在使用中...
有什么线索吗?