Question

我知道Linux中有页面缓存和缓冲区缓存。页面缓存用于文件系统，缓冲区缓存用于设备。

释放pagecache：

echo 1 > /proc/sys/vm/drop_caches

要释放dentries和inode：

echo 2 > /proc/sys/vm/drop_caches

释放pagecache，dentries和inode：

echo 3 > /proc/sys/vm/drop_caches

我的问题：

drop_caches中是否包含缓冲区缓存？

如果没有，那么是否有一种只释放缓冲区缓存的方法，让页面缓存仍然缓存？

如果没有，为什么它不必要或不可能？

Answer 1

Ans:-    

sync; echo 3 > /proc/sys/vm/drop_caches

Here’s the output of free before and after running the above command.

Before

# free -m
             total       used       free     shared    buffers     cached
Mem:           502        487         15          0         15        170
-/+ buffers/cache:        301        201
Swap:         3153        375       2777
After

# free -m
             total       used       free     shared    buffers     cached
Mem:           502        345        157          0          1         44
-/+ buffers/cache:        300        202
As you can see the highlighted numbers, the buffers and cached values have dropped significantly after I ran the command. Again, this is not necessary. In fact, it’s not recommended at all but there it is if you’re curious to know.

如何在Linux中只释放缓冲区缓存

1 个答案: