Re: [patch 016/104] epoll: introduce resource usage limits

On Wed, 28 Jan 2009, Bron Gondwana wrote:

On Tue, Jan 27, 2009 at 07:46:18PM -0800, Davide Libenzi wrote:
On Wed, 28 Jan 2009, Bron Gondwana wrote:

On Tue, Jan 27, 2009 at 04:35:19PM -0800, Greg KH wrote:
Can you resubmit all 4 patches, and cc: the epoll author, Davide? He's
the one that needs to accept these changes.

It's three now (two of them deserved to merged) and re-ordered so the
first two are trivial and the complex bits are easily skipped if you
don't want them.

Just looking for Davide's email address. Found it :) I'll follow up
this message with the patches. I'm not going to CC everyone else again
- but I'll CC LKML so you can follow it there if you want.

I already gave you my opinion on such code. There is no need for it. If
your servers are loaded, in the same way you bump NFILES (and likely
even other default configs), you bump up max_user_instances:

How can you tell if it's heavily loaded if you can't tell what the
current usage is? Just wait until you hit the limit?

In my servers, I know if they are going to be loaded, and I bump NFILES
(and a few other things) to the correct place. Since many of those
limits do not actually pre-allocate any resource, I don't need to wait and
monitor the values, before taking proper action.
Sorry, the whole patch set is a big NACK for many reasons.
We'd have happily avoided those limits altogether, but 100-160MB of kernel
memory able to be pinned by unprivileged users is easily a DoS on multiuser
systems.



- Davide


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