Linux：在Linux中查看进程占用内存大小的方法

た入场券 2024-03-03 08:20 116阅读 0赞

在开发和运维过程中，经常会遇到的问题是一个进程到底占用了多大的内存。以下通过常用的2个命令来说明如何获取进程占用的内存

比如有一个java进程，它的pid=7020

> $ps -ef | grep LogAgent | grep ^grep
> 
> usrapp 7020 1 0 15:23 ? 00:00:02 java -jar LogAgent.jar

#### **1、使用ps**  ####

> $ps -o vsz,rss,sz,size,pid -q7020 
> 
> VSZ RSS SZ SIZE PID 
> 
> 4444604 39160 1111151 4268292 7020

以上显示的数字的单位是KB ，其中vsz,rss,sz,size的含义如下：

<table style="width:683px;"> 
 <tbody> 
  <tr> 
   <td>name</td> 
   <td style="width:626px;">description</td> 
  </tr> 
  <tr> 
   <td>vsz</td> 
   <td style="width:626px;"> <p>virtual memory size of the process in KiB (1024-byte units).&nbsp; Device mappings are currently excluded; this is subject to change.&nbsp; (alias vsize).</p> </td> 
  </tr> 
  <tr> 
   <td>rss</td> 
   <td style="width:626px;"> <p>resident set size, the non-swapped physical memory that a task has used (in kiloBytes). (alias rssize, rsz).</p> </td> 
  </tr> 
  <tr> 
   <td>sz</td> 
   <td style="width:626px;"> <p>size in physical pages of the core image of the process.&nbsp; This includes text, data, and stack space.&nbsp; Device mappings are currently excluded; this is subject to change.&nbsp; See vsz and rss.</p> </td> 
  </tr> 
  <tr> 
   <td>size</td> 
   <td style="width:626px;">approximate amount of swap space that would be required if the process were to dirty all writable pages and then be swapped out. This number is very rough!</td> 
  </tr> 
 </tbody> 
</table>

####  ####

其中最关注的是RSS，它是实际占用的物理内存的大小。

#### 2、使用top  ####

> $top -n 1 -p 7020 
> 
> top - 16:29:32 up 166 days, 5:59, 3 users, load average: 0.25, 0.31, 0.48 
> 
> Tasks: 1 total, 0 running, 1 sleeping, 0 stopped, 0 zombie 
> 
> %Cpu(s): 0.0 us, 3.4 sy, 0.0 ni, 96.6 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st 
> 
> KiB Mem : 7388532 total, 158576 free, 5822636 used, 1407320 buff/cache 
> 
> KiB Swap: 16777212 total, 12173780 free, 4603432 used. 1012880 avail Mem 
> 
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+  COMMAND 
> 
> 7020 usrapp 20 0 4444604 39160 12444 S 0.0 0.5 0:02.15 java

从执行结果可以看到：

> ps. VSZ=top.VIRT
> 
> ps. RSS=top.RES

参考文档

[ps(1) - Linux manual page][ps_1_ - Linux manual page]

[top(1) - Linux manual page][top_1_ - Linux manual page]

[ps_1_ - Linux manual page]: https://www.man7.org/linux/man-pages/man1/ps.1.html
[top_1_ - Linux manual page]: https://www.man7.org/linux/man-pages/man1/top.1.html