From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753364AbbCBNy1 (ORCPT ); Mon, 2 Mar 2015 08:54:27 -0500 Received: from mail-qa0-f45.google.com ([209.85.216.45]:43946 "EHLO mail-qa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751357AbbCBNyZ (ORCPT ); Mon, 2 Mar 2015 08:54:25 -0500 Date: Mon, 2 Mar 2015 08:54:21 -0500 From: Tejun Heo To: Aleksa Sarai Cc: Austin S Hemmelgarn , Tim Hockin , Frederic Weisbecker , lizefan@huawei.com, richard@nod.at, mingo@redhat.com, cgroups@vger.kernel.org, peterz@infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC 0/2] add nproc cgroup subsystem Message-ID: <20150302135421.GB17694@htj.duckdns.org> References: <20150227114940.GB3964@htj.duckdns.org> <54F09E62.8000007@gmail.com> <20150227170640.GK3964@htj.duckdns.org> <54F0BC51.4050506@gmail.com> <20150228115926.GA1005@htj.duckdns.org> <20150228164353.GR3964@htj.duckdns.org> <54F461F3.3030903@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 03, 2015 at 12:31:19AM +1100, Aleksa Sarai wrote: > > If 16-bit PID's aren't a concern anymore, then why do we still default to > > treating it like a 16-bit signed int (the default for > > /proc/sys/kernel/pid_max is 32768)? > > I just want to emphasise that *even if* we changed to another default > limit, the mere existence of a system-wide pid_max makes PIDs a > resource. We seem to fail to communicate. The primary reason why pid promotes itself to a global resource status is because it's globally capped way below its backing resource's (kernel memory) limit and it is very difficult to make it not so due to direct userland dependencies on it. Thanks. -- tejun