Re: [RFC/PATCH -v2] Add sysfs control to modify a user's cpu share

Srivatsa Vaddagiri
2007-10-05T06:50:31Z

On Thu, Oct 04, 2007 at 05:32:17PM -0400, Valdis.Kletnieks@vt.edu wrote:
> > Shouldn't that be done via uevents? E.g. UID x gets added to the sysfs tree,
> > generates a uevent and a script then figures out the cpu_share and sets it.
>
> That would tend to be a tad racy - a site may want to set limits in the
> hypothetical /sys/kernel/uids/NNN before the program has a chance to fork-bomb
> or otherwise make it difficult to set a limitfrom within another userspace

Note that there is a default limit enforced on every new user (1024
value for the user's cpu share). This limit should contain any fork-bomb that
the user may launch immediately.

> process. It's similar to why you want a process to be launched with all its
> ulimit's set, rather than set them after the fork/exec happens...

--
Regards,
vatsa