Re: a lot of used inode in 2.1.x kernels

Bill Hawes (whawes@star.net)
Mon, 20 Jul 1998 09:12:58 -0400


Andrea Arcangeli wrote:

> The point is "why 2.1.x alloc so many inodes while 2.0.x not?". In 2.0.x
> the max_inodes is set to 3072 but after a "find /" I get only 400 inode
> allocated while 2.1.x always allocate more inodes than the max_inodes.
>
> In 2.1.110-pre2 after a "find /" with 32Mbyte:
>
> root@ark:/proc/sys/fs# cat inode-max
> 300
> root@ark:/proc/sys/fs# cat inode-nr
> 1232 7
>
> While in 2.0.x inode-max was 30xx and inode-nr was 300 or so on...

2.0 does many things differently. In the case of inodes, it does a deep
search (1/2 the number) each time, and only expands inodes when it has
to.

2.1 keeps dentries and inodes in use for longer, and expands the number
of inodes aggressively so that it can preserve the dentry information.
The max_inodes limit can be set by the administrator, so if you said
it's OK to use 4096 inodes, the sytem will use 4096 inodes.

Try timing the find operation and repeat it a few times under 2.0 and
2.1. You should see much faster operation under 2.1, at least until the
number of files greatly exceeds the inodes.

Regards,
Bill

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