From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
To: ebiederm@xmission.com (Eric W. Biederman)
Cc: Oleg Nesterov <oleg@redhat.com>,
linux-kernel@vger.kernel.org,
Linux Containers <containers@lists.linux-foundation.org>
Subject: Re: [RFC 0/4] reduce pid_namespace footprint when not configured
Date: Wed, 30 Sep 2015 23:34:02 +0200 [thread overview]
Message-ID: <87r3lfegmt.fsf@rasmusvillemoes.dk> (raw)
In-Reply-To: <87zj03ei64.fsf@x220.int.ebiederm.org> (Eric W. Biederman's message of "Wed, 30 Sep 2015 16:00:51 -0500")
On Wed, Sep 30 2015, ebiederm@xmission.com (Eric W. Biederman) wrote:
> Rasmus Villemoes <linux@rasmusvillemoes.dk> writes:
>
>> A few suggestions for reducing the footprint of pid namespaces when
>> CONFIG_PID_NS=n. The savings are admittedly not huge:
>>
>> $ scripts/bloat-o-meter /tmp/vmlinux.master vmlinux
>> add/remove: 0/7 grow/shrink: 30/25 up/down: 368/-1032 (-664)
>
> #ifdefs in C files.
> More code to maintain.
> Very minor savings.
>
> I don't think it is worth the pain. If anything I would prefer to
> remove CONFIG_PID_NS. The CONFIG_PID_NS ifdef really is about keeping
> from exposing people to the feature tha don't use it more than it is
> about size reduction.
>
> Or do you have a case where this makes the difference between a usable
> kernel and a kernel that is not?
No, it was mostly a small tinification effort, and we'd presumably also
save a few cycles on thread creation, but not anything measurable.
Rasmus
prev parent reply other threads:[~2015-09-30 21:34 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-30 20:49 Rasmus Villemoes
2015-09-30 20:49 ` [RFC 1/4] pid_namespace: remove ->level and ->parent for !CONFIG_PID_NS Rasmus Villemoes
2015-09-30 20:49 ` [RFC 2/4] pid_namespace: remove .kref field " Rasmus Villemoes
2015-09-30 20:49 ` [RFC 3/4] pid_namespace: make pid_nr_ns and pid_vnr static inlines " Rasmus Villemoes
2015-09-30 20:49 ` [RFC 4/4] pid_namespace: disable_pid_allocation is unused " Rasmus Villemoes
2015-09-30 21:00 ` [RFC 0/4] reduce pid_namespace footprint when not configured Eric W. Biederman
2015-09-30 21:34 ` Rasmus Villemoes [this message]
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