Linux in Memory view command free detailed

The free column of the add by zhj:-/+ Buffers/cache Row is the memory that is not actually used. The parameter-M in free-m refers to the output of data in megabytes

Original: http://liustb.blog.163.com/blog/static/1337080192011718112434416/

The Free command is used to view memory usage and is less expensive than the TOP command.

$free –m

Total used free shared buffers Cached

MEM:1002 769 232 0 62 421

-/+ Buffers/cache 286 715

Swap 1153 0 1153

Note: When you understand the output of the free command, you distinguish between two concepts: the first line (mem), which is for the operating system, and the buffer and cache for the operating system Is the memory that is used. The second line (-/+ Buffers/cache) is for the application, andfor the application,both the buffer and the cache belong to the memory that can be used.

So:

First Line ( mem):

Total: The amount of physical memory that the system can use is 1002;

Used indicates that the memory allocated is 769, including the buffer and cache memory 286 that have been actually used , theunused buffer Memory , unused cache Memory 421, i.e. 769 = + 421 + 286;

Free: Represents the allocated physical memory as 232;

Buffers: Buffer memory that has been allocated by the system but not used ;

Cached: The cache Memory 421 that has been allocated but not used;

second row ( -/+ buffers/cache);

Used: buffer and cache memory that have been really used by the application are 286;

Free: The memory that can be used by the application is 715, which includes: buffer memory that has been allocated but not used , cache memory allocated and unused 421 , has not been allocated memory 232, namely: 715 = + 421 + 232;

another: The difference between buffer and cache in Linux:

Buffer: The data memory to write to the hard disk;

Cache: Data memory read into memory;

Linux in Memory View command free detailed (GO)