Re: [rfc][patch] dynamic resizing dentry hash using RCU

From: Zach Brown
Date: Fri Feb 23 2007 - 12:55:50 EST

On Feb 23, 2007, at 7:37 AM, Nick Piggin wrote:

The dentry hash uses up 8MB for 1 million entries on my 4GB system is one
of the biggest wasters of memory for me. Because I rarely have more than one or
two hundred thousand dentries. And that's with several kernel trees worth of
entries. Most desktop and probably even many types of servers will only use a
fraction of that.

So I introduce a new method for resizing hash tables with RCU, and apply
that to the dentry hash.

Can you compare what you've done to the design that Paul and David talked about a year ago?

I'd love to see a generic implementation of RCU hashing that subsystems can then take advantage of. It's long been on the fun side of my todo list. The side I never get to :/.

- z

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