Linux--- 手工释放系统cache

Linux--- 手工释放系统cachelinux:/etc/rc.d # vmstatprocs -----------memory---------- ---swap-- -----io---- -system-- -----cpu------ r b swpd free buff cache si so bi bo in cs us sy id wa st 0 0 0 4205280 14880 2598540 0 0 0 12 11 12 0 1 98 1 0这个cache是系统从物理内存分配一块，用来做文件系统的读缓冲，按照Linux的说明在系统内存紧张时，这个内存是会自动释放的。手工释放caches的方法：sync;echo 3>/proc/sys/vm/drop_cachesWriting 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_cachesTo free dentries and inodes:* echo 2 > /proc/sys/vm/drop_cachesTo free pagecache, dentries and inodes:* echo 3 > /proc/sys/vm/drop_cachesAs this is a non-destructive operation, and dirty objects are notfreeable, the user should run "sync" first in order to make sure allcached objects are freed.This tunable was added in 2.6.16.本文永久更新链接地址