我的系统中安装了 32GB 内存，但运行一两天后，内存开始不知何故增加。使用free，系统声称正在使用 27 个可用内存中的 8.9GB：
jeff@pop-os:~$ free -h
total used free shared buff/cache available
Mem: 27Gi 8.9Gi 12Gi 540Mi 5.4Gi 15Gi
Swap: 23Gi 241Mi 23Gi
top证实了这一点，称正在使用 9GB。
jeff@pop-os:~$ top
top - 23:15:51 up 12:34, 1 user, load average: 0.51, 0.91, 1.25
Tasks: 559 total, 2 running, 556 sleeping, 0 stopped, 1 zombie
top - 23:16:04 up 12:35, 1 user, load average: 0.47, 0.88, 1.23
Tasks: 559 total, 1 running, 557 sleeping, 0 stopped, 1 zombie
%Cpu(s): 1.0 us, 1.7 sy, 0.9 ni, 96.1 id, 0.1 wa, 0.0 hi, 0.0 si, 0.0 st
MiB Mem : 27906.3 total, 13294.2 free, 9004.8 used, 5607.3 buff/cache
MiB Swap: 24131.5 total, 23890.5 free, 241.0 used. 16519.6 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
5003 jeff 17 -3 4360484 439680 137132 S 10.6 1.5 54:30.51 gnome-shell
242867 jeff 17 -3 1368008 180628 31488 S 10.0 0.6 10:36.26 python3
5826 jeff 26 6 32.4g 266512 113564 S 7.3 0.9 88:07.44 code-insiders
4841 jeff 17 -3 25.0g 222276 115132 S 6.6 0.8 22:56.82 Xorg
282966 jeff 26 6 33.1g 719120 457248 S 4.3 2.5 1:16.06 chrome
5960 jeff 26 6 1130.0g 265240 104044 S 3.7 0.9 48:17.31 code-insiders
282086 jeff 20 0 571220 62248 40924 S 3.7 0.2 0:04.14 gnome-terminal-
22297 jeff 26 6 1129.9g 481488 106444 S 3.0 1.7 52:37.24 code-insiders
5952 jeff 26 6 1129.9g 212484 96116 S 2.3 0.7 18:23.47 code-insiders
11636 jeff 26 6 1137.3g 423932 150340 S 2.0 1.5 17:19.96 Discord
267139 jeff 20 0 3138796 314556 111700 S 1.7 1.1 4:45.19 Isolated Web Co
283220 jeff 26 6 1131.0g 157136 117536 S 1.3 0.5 0:02.01 chrome
842 root -51 0 0 0 0 S 1.0 0.0 8:51.13 irq/94-nvidia
283014 jeff 26 6 32.7g 290320 165980 S 1.0 1.0 0:20.84 chrome
879 root 32 12 2812 2144 1924 S 0.7 0.0 1:02.21 acpid
281955 root 20 0 0 0 0 D 0.7 0.0 0:00.31 kworker/u32:0+events_unbound
283015 jeff 20 0 32.4g 125364 96720 S 0.7 0.4 0:05.89 chrome
14 root 20 0 0 0 0 S 0.3 0.0 0:05.73 ksoftirqd/0
710 root -51 0 0 0 0 S 0.3 0.0 5:22.12 irq/93-rtw89_pci
886 root 32 12 153956 6336 5616 S 0.3 0.0 0:12.25 system76-power
1168 root 32 12 2319660 52584 33364 S 0.3 0.2 0:38.67 containerd
然而，将所有%MEM使用量加起来总共为 14.5%，总计不到 4GB（假设总计 27GB 的低端）。这使得 4GB 下落不明——它去哪儿了？
帮助调试的代码输出：
jeff@pop-os:~$ cat /proc/meminfo
MemTotal: 28576036 kB
MemFree: 14337988 kB
MemAvailable: 17364024 kB
Buffers: 111756 kB
Cached: 4890460 kB
SwapCached: 120 kB
Active: 7282988 kB
Inactive: 5117764 kB
Active(anon): 5806232 kB
Inactive(anon): 1964132 kB
Active(file): 1476756 kB
Inactive(file): 3153632 kB
Unevictable: 320 kB
Mlocked: 320 kB
SwapTotal: 24710644 kB
SwapFree: 24433396 kB
Zswap: 0 kB
Zswapped: 0 kB
Dirty: 9512 kB
Writeback: 0 kB
AnonPages: 7398644 kB
Mapped: 1884072 kB
Shmem: 371896 kB
KReclaimable: 305196 kB
Slab: 628552 kB
SReclaimable: 305196 kB
SUnreclaim: 323356 kB
KernelStack: 34732 kB
PageTables: 98480 kB
SecPageTables: 0 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 38998660 kB
Committed_AS: 22911908 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 292844 kB
VmallocChunk: 0 kB
Percpu: 21568 kB
HardwareCorrupted: 0 kB
AnonHugePages: 2048 kB
ShmemHugePages: 0 kB
ShmemPmdMapped: 0 kB
FileHugePages: 0 kB
FilePmdMapped: 0 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
Hugetlb: 0 kB
DirectMap4k: 1423812 kB
DirectMap2M: 25688064 kB
DirectMap1G: 2097152 kB
jeff@pop-os:~$ df -h
Filesystem Size Used Avail Use% Mounted on
tmpfs 2.8G 3.6M 2.8G 1% /run
/dev/nvme1n1p7 316G 271G 30G 91% /
tmpfs 14G 421M 14G 4% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
/dev/nvme0n1 916G 627G 243G 73% /home/jeff/SSD_2
/dev/nvme1n1p5 5.3G 267M 5.0G 5% /boot/efi
tmpfs 2.8G 284K 2.8G 1% /run/user/1000
jeff@pop-os:~$ mount | grep tmpfs
udev on /dev type devtmpfs (rw,nosuid,relatime,size=14222632k,nr_inodes=3555658,mode=755,inode64)
tmpfs on /run type tmpfs (rw,nosuid,nodev,noexec,relatime,size=2857604k,mode=755,inode64)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev,inode64)
tmpfs on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k,inode64)
tmpfs on /run/user/1000 type tmpfs (rw,nosuid,nodev,relatime,size=2857600k,nr_inodes=714400,mode=700,uid=1000,gid=1000,inode64)
jeff@pop-os:~$ df -h
Filesystem Size Used Avail Use% Mounted on
tmpfs 2.8G 3.6M 2.8G 1% /run
/dev/nvme1n1p7 316G 271G 30G 91% /
tmpfs 14G 421M 14G 4% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
/dev/nvme0n1 916G 627G 243G 73% /home/jeff/SSD_2
/dev/nvme1n1p5 5.3G 267M 5.0G 5% /boot/efi
tmpfs 2.8G 284K 2.8G 1% /run/user/1000
jeff@pop-os:~$ neofetch
///////////// jeff@pop-os
///////////////////// -----------
///////*767//////////////// OS: Pop!_OS 22.04 LTS x86_64
//////7676767676*////////////// Host: 82JY Legion 5 17ACH6H
/////76767//7676767////////////// Kernel: 6.2.6-76060206-generic
/////767676///*76767/////////////// Uptime: 12 hours, 45 mins
///////767676///76767.///7676*/////// Packages: 3116 (dpkg), 14 (flatpak), 9 (snap)
/////////767676//76767///767676//////// Shell: bash 5.1.16
//////////76767676767////76767///////// Resolution: 1600x900, 1920x1080
///////////76767676//////7676////////// DE: GNOME 42.5
////////////,7676,///////767/////////// WM: Mutter
/////////////*7676///////76//////////// WM Theme: Pop
///////////////7676//////////////////// Theme: Gruvbox-Dark-BL [GTK2/3]
///////////////7676///767//////////// Icons: Uniform+ [GTK2/3]
//////////////////////'//////////// Terminal: gnome-terminal
//////.7676767676767676767,////// CPU: AMD Ryzen 7 5800H with Radeon Graphics (16) @ 3.200GHz
/////767676767676767676767///// GPU: AMD ATI 06:00.0 Cezanne
/////////////////////////// GPU: NVIDIA GeForce RTX 3060 Mobile / Max-Q
///////////////////// Memory: 9847MiB / 27906MiB
/////////////