Re: [PATCH 3/7] sysfs: Keep an nlink count on sysfs directories.

From: Tejun Heo
Date: Mon Jan 11 2010 - 19:45:16 EST


On 01/12/2010 05:21 AM, Eric W. Biederman wrote:
> On large directories sysfs_count_nlinks can be a significant
> bottleneck, so keep a count in sysfs_dirent.

I was about to suggest changing s_flags to ushort too. Hmmm... adding
a new field to sysfs_dirent somewhat worries me but this doesn't add
to the size of the structure. How significant bottlenect are we
talking about?

> If we exceed the maximum number of directory entries we can store
> return nlink of 1. An nlink of 1 matches what reiserfs does in this
> case, and it let's find and similar utlities know that we have a the
> directory nlink can not be used for optimization purposes.

Hmmm... what's the limit on reiserfs? Is it 64k too?


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