linux清理内存命令

经常操作内存之后不免使系统变的比较慢，内存的碎块也较多，有必要进行清理，搜索下网络之后，得到如下清理方法，效果还不错。

Writing to this will cause the kernel to drop clean caches, dentries and inodes from memory, causing that memory to become free.

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

As this is a non-destructive operation, and dirty objects are not freeable, the user should run “sync” first in order to make sure all cached objects are freed.

This tunable was added in 2.6.16.

the last:
echo 0 > /proc/sys/vm/drop_caches

should operator in root !