我们如何通过总结进程占用的内存和linux中的可用内存来达到RAM大小? [英] how we can reach at RAM size by summing up the memory occupied by processes and free memory in linux?

问题描述

我想知道如何计算总RAM，如何通过汇总"cat proc/meminfo"命令的输出来达到RAM大小

Memtotal = MemFree +?...........

任何人都可以帮助

解决方案

您需要一个将共享内存考虑在内的工具.

例如 smem :

# smem -t
  PID User     Command                         Swap      USS      PSS      RSS
...
10593 root     /usr/lib/chromium-browser/c        0    22868    26439    49364 
11500 root     /usr/lib/chromium-browser/c        0    22612    26486    49732 
10474 browser  /usr/lib/chromium-browser/c        0    39232    43806    61560 
 7777 user     /usr/lib/thunderbird/thunde        0    89652    91118   102756 
-------------------------------------------------------------------------------
  118 4                                       40364   594228   653873  1153092 

PSS是有趣的一列，因为它考虑了共享内存(将RSS加在一起将导致对共享内存段进行多次计数，因此不会累加数字).

因此，用户层进程在这里总共占用654Mb.

# smem -tw
Area                           Used      Cache   Noncache 
firmware/hardware                 0          0          0 
kernel image                      0          0          0 
kernel dynamic memory        345784     297092      48692 
userspace memory             654056     181076     472980 
free memory                   15828      15828          0 
----------------------------------------------------------
                            1015668     493996     521672 

346Mb被内核使用，并且有16Mb的空闲空间.
总体上，大约一半的内存用于缓存(494Mb).

因此1Gb的 _RAM总数 = 654Mb的 _{userland进程，按上述方式分解} + 346Mb的 _{kernel mem} + 16Mb的 _free >
(提供或占用几Mb)

I want to know to how to calculate total RAM, how we can reach at RAM size by summing up the output of "cat proc/meminfo" command

Memtotal = MemFree+?...........

any one can help

解决方案

You need a tool that takes shared memory into account to do this.

For example, smem:

# smem -t
  PID User     Command                         Swap      USS      PSS      RSS
...
10593 root     /usr/lib/chromium-browser/c        0    22868    26439    49364 
11500 root     /usr/lib/chromium-browser/c        0    22612    26486    49732 
10474 browser  /usr/lib/chromium-browser/c        0    39232    43806    61560 
 7777 user     /usr/lib/thunderbird/thunde        0    89652    91118   102756 
-------------------------------------------------------------------------------
  118 4                                       40364   594228   653873  1153092 

PSS is the interesting column here because it takes shared memory into account (adding RSS together will result in shared mem segments being counted multiple times so numbers won't add up).

So userland processes take up 654Mb total here.

# smem -tw
Area                           Used      Cache   Noncache 
firmware/hardware                 0          0          0 
kernel image                      0          0          0 
kernel dynamic memory        345784     297092      48692 
userspace memory             654056     181076     472980 
free memory                   15828      15828          0 
----------------------------------------------------------
                            1015668     493996     521672 

346Mb is used by the kernel and there's 16Mb free.
Overall about half of memory is used for cache (494Mb).

So 1Gb _{RAM total} = 654Mb _{userland processes, broken up as above} + 346Mb _{kernel mem} + 16Mb _free
(give or take a few Mb)

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