From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932318Ab3FLXed (ORCPT ); Wed, 12 Jun 2013 19:34:33 -0400 Received: from mail-gh0-f175.google.com ([209.85.160.175]:63107 "EHLO mail-gh0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932259Ab3FLXeW (ORCPT ); Wed, 12 Jun 2013 19:34:22 -0400 Date: Wed, 12 Jun 2013 16:34:17 -0700 From: Tejun Heo To: Kent Overstreet Cc: Tejun Heo , linux-kernel@vger.kernel.org, Rusty Russell , Oleg Nesterov , Christoph Lameter Subject: Re: [PATCH 2/2] percpu-refcount: implement percpu_tryget() along with percpu_ref_kill_and_confirm() Message-ID: <20130612233417.GA978@mtj.dyndns.org> References: <20130612204532.GB15092@htj.dyndns.org> <20130612204627.GC15092@htj.dyndns.org> <20130612210824.GG6151@google.com> <20130612211747.GA2866@htj.dyndns.org> <20130612214630.GH6151@google.com> <20130612233151.GA32700@mtj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130612233151.GA32700@mtj.dyndns.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 12, 2013 at 04:31:51PM -0700, Tejun Heo wrote: > The original intention of the nested refcnting probably is allowing > draining css's separately so that subsystems can be added and removed > from an existing hierarchy. That never worked out, so it could be > that we can collapse all the css refcnts into cgroup refcnt, which BTW > is currently using the dentry reference count. I'm fairly certain > that we can collapse it but that's a separate issue we can deal with > later. Hmmm.... I *think* we might need per-css refcnts to implement unified hierarchy to allow turning on and off controllers along the single hierarchy. I'll think more about it but this is sorta off topic for this series. Thanks. -- tejun