Re: the new VMt

Andrey Savochkin
2000-09-27T10:20:28Z

On Tue, Sep 26, 2000 at 11:45:02AM -0600, Erik Andersen wrote:
[snip]
> "Overcommit" to me is the same things as Mark Hemment stated earlier in this
> thread -- the "fact that the system has over committed its memory resources.
> ie. it has sold too many tickets for the number of seats in the plane, and all
> the passengers have turned up." Basically any case where too many tickets
> have been sold (applied to the entire system, and all subsystems).
[snip]
> If the Beancounter patch lets the kernel count "passengers", classify them
> (with user hinting) so the pilot and flight attendants (init, X, or whatever)
> always stay on the plane, and has some sane predictable mechanism for booting
> non-priveledged passengers, then I am all for it.

That's exactly what I'm doing.

> How does one provide the kernel with hints as to which processes are sacred?
> Where does one find this beancounter patch? How much weight does it add to
> the kernel?

ftp://ftp.sw.com.sg/pub/Linux/people/saw/kernel/user_beancounter/UserBeancounter.html

The current version has some drawbacks, and one of them is the performance.
Memory accounting is implemented as a kernel thread which goes through page
tables of processes (similar to kswapd), and it appears to consume 1-5% of
CPU (depending on number of processes). I consider it unacceptable, and have
started reimplementation of the process memory accounting from the beginning.

Best regards
Andrey