Messages in this thread | | | Date | Mon, 11 Jan 2010 19:53:08 -0500 | From | Benjamin LaHaise <> | Subject | Re: [PATCH 3/7] sysfs: Keep an nlink count on sysfs directories. |
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On Tue, Jan 12, 2010 at 09:46:59AM +0900, Tejun Heo wrote: > Hello, > > 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?
100,000 entries in a sysfs directory is a requirement for network devices.
> > 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?
64k is too small. 10 gig interfaces can currently service 50-100k users, each of which requires their own network device.
-ben
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