# cat free
total used free
shared buffers cached
Mem:
24674784 24576836 97948 0
351244 21165268
-/+ buffers/cache:
3060324
21614460<<<<-----actual buffers="" cached="" free="" memory="" p="">
= + +
= - - -
= -
Swap:
25165808 1084452 24081356
Total Physical
Memory = 24674784 KB = 24096 MB
Physically Used
Memory = 24576836 KB = 24000 MB
Actual used
memory = 3060324 KB = 2988 MB = ~3 GB
buffers =
351244 KB = 343 MB
cached =
21165268 KB = 20669 MB = ~20 GB
Physically Free
Memory = 97948 KB = 95 MB
Memory free for
Applications = 21614460 KB = 21107 MB = ~20 GB
The items to note here are:
The philosophy in Linux is that an unused resource is a
wasted resource. The kernel therefore will use as much RAM as it can to cache
information from your local and remote filesystems and disks. This builds up
over time as reads and writes are done on the system trying to keep the data
stored in RAM as relevant as possible to the processes that have been running
on your system.
This caching is reported by the system as the sum of two
numbers, buffers and pagecache. The cache is reclaimed, not at the time of
process exit (you might start up another process soon that needs the same
data), but upon demand - i.e. When you start a process that needs a lot of
memory to run, the Linux kernel will reclaim memory that had been storing
cached data and give it to the new process.
Refer below article for detail information on this:
What is cache memory and why is memory utilization high
for cache memory?
Why is so much of my memory used by cache?
