Check Linux memory usage

1. To view the process memory usage of the root user, you can use the following command:
$ top-u Oracle

Content Explanation:
PID: ID of the process
USER: Process Owner
PR: The priority level of the process, the smaller the higher the priority is executed
Ninice: Value
VIRT: Virtual memory consumed by the process
RES: The physical memory occupied by the process
SHR: Shared memory used by the process
S: The state of the process. s for hibernation, R for running, Z for Zombie, n for the process priority value is negative
%CPU: Process Consuming CPU utilization
%MEM: The percentage of physical memory and total memory used by the process
Time+: The total CPU time that is consumed after the process is started, which is the cumulative value of the CPU usage time.
Command: Process start name

注释：      输入top命令后，按键盘“P”，执行按%CPU使用率排行

After entering the top command, press "T" on the keyboard to perform the mite+ ranking
After entering the top command, press the keyboard "M" to perform the%mem ranking

• 2, according to the process to see the memory of the process related information, (process number can be viewed through PS) as follows:
  $ pmap-d 14596

• 3. See how much memory is actually used
  To view memory usage for all processes in the system, execute the following command:
  $ ps-e-O ' pid,comm,args,pcpu,rsz,vsz,stime,user,uid '

  查看系统指定进程Oracle的内存使用量，执行以下命令：

  $ ps-e-o ' pid,comm,args,pcpu,rsz,vsz,stime,user,uid ' | grep Oracle | Sort-nrk5

Comments:
Where Rsz is the actual memory, the above example is implemented by memory sort, from large to small

• 4. See the N processes that currently occupy the most memory
  $ps-aux | Sort-k4nr | Head-n
  If it is 10 processes, n=10, if it is the highest three, n=3, for example $ps-aux | Sort-k4nr | Head-3
  Use the most CPU K processes
  $ps-aux | Sort-k3nr | Head-k

Check Linux memory usage