[Devel] Re: How Inactive may be much greather than cached?

[Nick Piggin]

Hi,

On Thursday 18 October 2007 16:24, Vasily Averin wrote:
> Hi all,
>
> could anybody explain how "inactive" may be much greater than "cached"?
> stress test (http://weather.ou.edu/~apw/projects/stress/) that writes into
> removed files in cycle puts the node to the following state:
>
> MemTotal: 16401648 kB
> MemFree: 636644 kB
> Buffers: 1122556 kB
> Cached: 362880 kB
> SwapCached: 700 kB
> Active: 1604180 kB
> Inactive: 13609828 kB
>
> At the first glance memory should be freed on file closing, nobody refers
> to file and ext3_delete_inode() truncates inode. We can see that memory is
> go away from "cached", however could somebody explain why it become
> "invalid" instead be freed? Who holds the references to these pages?

Buffers, swap cache, and anonymous.