zz Release memory in Linux (Unused or Cached)

In computer science, Memory Leakage occurs when a computer software or program consumes required memory but unable to memory after completing its task or when no longer needed to Operating System. There are two types of Memory Leakage. One is Virtual Memory Leakage and another is Real Memory Leakage.

 

Now first Identify cached memory or unused memory by executing,

 

# free -m

 
total
used
free
shared
Mem:
3991
2674
1317
0
-/+ buffers/cache:
 
753
3238
 
Swap:
1023
0
1023
 
 

Flush file system buffers by executing,

 

# sync

 

Kernels 2.6.16.x and newer versions of kernel provide a mechanism to have the kernel drop the page cache and/or inode and dentry caches on command, which can be helpful to free up a lot of memory.

 

To free page cache:

# echo 1 > /proc/sys/vm/drop_caches

 

To free dentries and inodes:

# echo 2 > /proc/sys/vm/drop_caches

 

To free page cachedentries and inodes:

echo 3 > /proc/sys/vm/drop_caches

 

Above commands are non-destructive and will only release unused memory. As we have used sync, so it will flush all Dirty Objects which are not free able and make it as unused memory.

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