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clean up memory on linux

Terminal - clean up memory on linux
sync; echo 3 | sudo tee /proc/sys/vm/drop_caches
2010-05-23 11:39:35
User: bandie91
Functions: echo sudo sync tee
7
Up
Down
clean up memory on linux

where proc filesystem mounted under /proc

Show sample output | Add to favourites | Report as malicious

Alternatives

There are 2 alternatives - vote for the best!

Terminal - Alternatives
free && sync && echo 3 > /proc/sys/vm/drop_caches && free
2009-08-05 23:44:34
User: ricardoarguello
Functions: echo free sync
34
Up
Down
Release memory used by the Linux kernel on caches

The Linux kernel uses unused memory in caches. When you execute "free" you never get the "real" available memory.

Show sample output | Comments (4) | Add to favourites | Report as malicious
sync && echo 1 > /proc/sys/vm/drop_caches
2011-06-10 07:32:28
User: KeePon
Functions: echo sync
Tags: memory ram kernel sync cache free
17
Up
Down
clean up memory of unnecessary things (Kernerl 2.6.16 or newer)

run sync first to flush useful things out to disk!!!

To free pagecache:

echo 1 > /proc/sys/vm/drop_caches

To free dentries and inodes:

echo 2 > /proc/sys/vm/drop_caches

To free pagecache, dentries and inodes:

echo 3 > /proc/sys/vm/drop_caches

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sync && echo 3 | sudo tee /proc/sys/vm/drop_caches
2011-10-18 15:22:25
User: mariusbutuc
Functions: echo sudo sync tee
Tags: cache
6
Up
Down
Clear filesystem memory cache

Found here: http://ubuntuforums.org/showthread.php?t=589975

Comments (0) | Add to favourites | Report as malicious
/sbin/sysctl -w vm.drop_caches=3
2012-08-05 22:09:04
User: jlaunay
4
Up
Down
Release memory used by the Linux kernel on caches

=1 --> to free pagecache

=2 --> to free dentries and inodes

=3 --> to free pagecache, dentries and inodes

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sync && echo 3 > /proc/sys/vm/drop_caches
2009-02-19 15:54:22
User: skygreg
Functions: echo sync
3
Up
Down
Empty the linux buffer cache
Comments (0) | Add to favourites | Report as malicious

Know a better way?

If you can do better, submit your command here.

What others think

Why would you want to do this?

Comment by DNSpyder 160 weeks and 2 days ago

Nice, but what would you use it for other than prettying up /usr/bin/free for management's consumption?

Comment by sufoo 160 weeks and 2 days ago

Buffers and caches in linux only use unused memory, i.e. memory not used by processes. So it's incorrect to think that you are making more memory available for programs by using this, in general. As soon as an application makes a big memory request, the kernel may satisfy that request by "dropping" enough buffers or cache to satisfy the request. Because unused memory is a terrible thing to waste. :-) If you do this, and then want to cache a file's contents (if there is memory available) then simply do

cat filename > /dev/null

if you run htop you can see the cache fill up as cat reads this file and automatically uses cache if it can.

Comment by bwoodacre 160 weeks and 2 days ago

bwoodacre: its news for me.

i had hope it decrease number of pagefaults

Comment by bandie91 160 weeks and 1 day ago

under what situation i should use this command??

Comment by criver 158 weeks and 3 days ago

Your point of view

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