10GB memorys occupied by XFS

[Stan Hoeppner]

On 4/4/2014 2:26 AM, daiguochao wrote:
> Hello folks,

Hello,

Note that your problems are not XFS specific, but can occur with any
Linux filesystem.

> I used xfs file system in kernel-2.6.32-220.13.1.el6.x86_64 for store
> pictures. About 100 days system memorys is lost and some nginx process is
> killed by oom-killer.So,I looked /proc/meminfo and find memorys is
> lost.Finally, I try to umount xfs system and 10GB memorys is coming back. l
> look xfs bugzilla no such BUG.I have no idea for it.
> 
> Cheers,
> 
> Guochao.
> 
> some memorys info:
> 
> 0> free -m
>              total       used       free     shared    buffers     cached
> Mem:         11887      11668        219          0          0          2
> -/+ buffers/cache:      11665        222
> Swap:            0          0          0


First problem:  no swap
Second problem: cache is not being reclaimed

Read vfs_cache_pressure at:
https://www.kernel.org/doc/Documentation/sysctl/vm.txt

You've likely set this value to zero.  Changing it to 200 should prompt
the kernel to reclaim dentries and inodes aggressively, preventing the
oom-killer from kicking in.

Cheers,

Stan