手动释放linux内存和缓存

/proc/sys/vm/drop_caches (since Linux
2.6.16)
Writing to this file causes the kernel to drop clean
caches,
dentries and inodes from memory, causing that memory to
become
free.

To free pagecache, use echo 1
> /proc/sys/vm/drop_caches; to
free dentries and inodes, use
echo 2 > /proc/sys/vm/drop_caches;
to free pagecache,
dentries and inodes, use echo 3
>
/proc/sys/vm/drop_caches.

Because this
is a non-destructive operation and dirty objects
are not
freeable, the user should run sync first.