How To Free Linux Cache


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These commands will cause the kernel to drop clean caches, dentries and inodes from memory.

To free pagecache:

  • sudo sync echo 1 > /proc/sys/vm/drop_caches

To free dentries and inodes:

  • sudo sync echo 2 > /proc/sys/vm/drop_caches

To free pagecache, dentries and inodes:

  • sudo sync 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.