为什么我手机 8g 内存这么不耐用

开个微信小程序就省 1G 可用内存了. 我用 top 命令查了一下内存占用, 显示的这些加起来占用才 16.8%

[s [999C [999B [6n [u [H [J [?25l [H [J [s [999C [999B [6n [uTasks: 824 total, 4 running, 816 sleeping, 0 stopped, 4 zombie

Mem: 7349100K total, 7165860K used, 183240K free, 1088K buffers

Swap: 0K total, 0K used, 0K free, 863984K cached

800%cpu 14%user 0%nice 121%sys 2790%idle 0%iow 10%irq 7%sirq 3438%host

[7m PID USER PR NI VIRT RES SHR S[%CPU] %MEM TIME+ ARGS [0m

1132 system 20 0 2.2G 5.2M 2.3M S 44.8 0.0 6:26.21 android.system.+

[1m19733 shell 20 0 2.0G 4.8M 3.7M R 13.7 0.0 0:00.06 top [m 18403 u0_a290 20 0 8.2G 197M 72M S 3.4 2.7 0:14.57 com.estrongs.an+

2896 root 20 0 0 0 0 I 3.4 0.0 0:00.62 [kworker/1:2-ev+

[1m31257 root 0 -20 0 0 0 R 3.4 0.0 0:21.85 [kworker/u17:0++ [m 29142 root 20 0 0 0 0 I 3.4 0.0 0:13.58 [kworker/u16:17+

32576 root 20 0 0 0 0 I 3.4 0.0 0:32.64 [kworker/u16:3-+

20873 root 20 0 0 0 0 I 3.4 0.0 0:25.92 [kworker/u16:16+

12230 system 20 0 6.4G 61M 10M S 3.4 0.8 0:01.31 com.xiaomi.aias+

11255 u0_a253 20 0 7.1G 75M 8.9M S 3.4 1.0 1:10.87 com.github.kr32+

4743 system 20 0 8.2G 293M 69M S 3.4 4.0 4:01.95 com.android.sys+

2754 radio 20 0 2.1G 2.4M 1.4M S 3.4 0.0 0:01.43 qti

2645 system 20 0 2.5G 2.6M 988K S 3.4 0.0 0:01.83 qcc-vendor

2581 radio 20 0 2.2G 2.2M 1.4M S 3.4 0.0 0:00.90 port-bridge

2570 radio 20 0 2.7G 3.7M 348K S 3.4 0.0 0:07.27 imsdaemon

2563 mediacodec 20 0 24M 2.1M 336K S 3.4 0.0 0:00.49 media.codec hw/+

2488 radio 20 0 4.3G 10M 384K S 3.4 0.1 0:21.40 qcrilNrd

2186 system 18 -2 12G 338M 117M S 3.4 4.7 21:51.23 system_server

1708 system 20 0 2.9G 7.3M 2.8M S 3.4 0.1 0:03.37 mifaced@1.0