Re: Minutes from Feb 21 LSE Call

Eric W. Biederman
2003-02-23T00:32:48Z

Hanna Linder <hannal@us.ibm.com> writes:

> LSE Con Call Minutes from Feb21
>
> Minutes compiled by Hanna Linder hannal@us.ibm.com, please post
> corrections to lse-tech@lists.sf.net.
>
> Object Based Reverse Mapping:
> (Dave McCracken, Ben LaHaise, Rik van Riel, Martin Bligh, Gerrit Huizenga)
>

> Ben said none of the users have been complaining about
> performance with the existing rmap. Martin disagreed and said Linus,
> Andrew Morton and himself have all agreed there is a problem.
> One of the problems Martin is already hitting on high cpu machines with
> large memory is the space consumption by all the pte-chains filling up
> memory and killing the machine. There is also a performance impact of
> maintaining the chains.

Note: rmap chains can be restricted to an arbitrary length, or an
arbitrary total count trivially. All you have to do is allow a fixed
limit on the number of people who can map a page simultaneously.

The selection of which chain to unmap can be a bit tricky but is
relatively straight forward. Why doesn't someone who is seeing
this just hack this up?

Eric