Re: [PATCH v7 0/8] Request for inclusion: tcp memory buffers

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On 10/14/2011 12:12 AM, David Miller wrote:
From: Glauber Costa<glommer@xxxxxxxxxxxxx>
Date: Fri, 14 Oct 2011 00:05:58 +0400

Also, I kind of dispute the affirmation that !cgroup will encompass
the majority of users, since cgroups is being enabled by default by
most vendors. All systemd based systems use it extensively, for
instance.

I will definitely advise people against this, since the cost of having
this on by default is absolutely non-trivial.

People keep asking every few releases "where the heck has my performance
gone" and it's because of creeping features like this.  This socket
cgroup feature is a prime example of where that kind of stuff comes
from.

I really get irritated when people go "oh, it's just one indirect
function call" and "oh, it's just one more pointer in struct sock"

We work really hard to _remove_ elements from structures and make them
smaller, and to remove expensive operations from the fast paths.

It might take someone weeks if not months to find a way to make a
patch which compensates for the extra overhead your patches are adding.

And I don't think you fully appreciate that.

Let's focus on this:
Are you happy, or at least willing to accept, an approach that keep things as they were with cgroups *compiled out*, or were you referring to not in use == compiled in, but with no users?

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