Re: [patch] drop epoll max_user_instances and rely only on max_user_watches

[Greg KH <gregkh@suse.de>]

On Thu, Jan 29, 2009 at 11:03:37PM +1300, Michael Kerrisk wrote:
> On Thu, Jan 29, 2009 at 9:57 PM, Andrew Morton
> <akpm@linux-foundation.org> wrote:
> >
> >> Subject: [patch] drop epoll max_user_instances and rely only on max_user_watches
> >
> > nanonit: please prepare titles in the form "subsystem-id:
> > what-i-did-to-it", so a suitable name here would be
> >
> >        epoll: drop max_user_instances and rely only on max_user_watches
> >
> > On Wed, 28 Jan 2009 20:56:07 -0800 (PST) Davide Libenzi <davidel@xmailserver.org> wrote:
> >
> >> Linus suggested to put limits where the money is, and max_user_watches
> >> already does that w/out the need of max_user_instances. That has the
> >> advantage to mitigate the potential DoS while allowing pretty generous
> >> default behavior.
> 
> [...]
> 
> > I assume that because you based all this on all the other patches, you
> > view it as 2.6.30 material?
> 
> Since max_user_instances was added in 2.6.28, and this is an ABI
> change, I suggest this should go into .29-rc, so that
> max_user_instances spends as little time in the wild as possible.

I agree.  I'll backport the change to the .28 and .27 stable kernels as
well, as we have complaints about the default values breaking people's
machines.

thanks,

greg k-h