From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oren Laadan Subject: Re: [PATCH 10/30] cr: core stuff Date: Tue, 14 Apr 2009 01:52:35 -0400 Message-ID: <49E424A3.60606@cs.columbia.edu> References: <20090410023539.GK27788@x200.localdomain> <20090413214701.GA24509@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090413214701.GA24509-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: "Serge E. Hallyn" Cc: xemul-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, mingo-X9Un+BFzKDI@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, Alexey Dobriyan List-Id: containers.vger.kernel.org Hi, Serge E. Hallyn wrote: > Quoting Alexey Dobriyan (adobriyan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org): > > Hi Alexey, > > as far as I can see, the main differences between this patch and the > equivalent in Oren's tree are: > > 1. kernel auto-selects container init to freeze Actually, this eliminates the possibility to checkpoint a subtree of tasks, which (under some obvious constraints) can be a handy feature. > 2. kernel freezes tasks IMHO better to do it in userspace - that way userspace can accomplish other tasks while tasks are frozen, such as snapshot the filesystem, or block/unblock the network. Is there a good argument to do it kernel ? > 3. no objhash taking references > 4. no hbuf > 5. always require CAP_SYS_ADMIN I'm now convinced (thanks, Serge!) that it's better not to require this unless we strictly have to. Oren. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752505AbZDNFzR (ORCPT ); Tue, 14 Apr 2009 01:55:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751035AbZDNFzB (ORCPT ); Tue, 14 Apr 2009 01:55:01 -0400 Received: from brinza.cc.columbia.edu ([128.59.29.8]:59278 "EHLO brinza.cc.columbia.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750983AbZDNFzB (ORCPT ); Tue, 14 Apr 2009 01:55:01 -0400 Message-ID: <49E424A3.60606@cs.columbia.edu> Date: Tue, 14 Apr 2009 01:52:35 -0400 From: Oren Laadan Organization: Columbia University User-Agent: Mozilla-Thunderbird 2.0.0.19 (X11/20090103) MIME-Version: 1.0 To: "Serge E. Hallyn" CC: Alexey Dobriyan , akpm@linux-foundation.org, containers@lists.linux-foundation.org, xemul@parallels.com, dave@linux.vnet.ibm.com, mingo@elte.hu, hch@infradead.org, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 10/30] cr: core stuff References: <20090410023539.GK27788@x200.localdomain> <20090413214701.GA24509@us.ibm.com> In-Reply-To: <20090413214701.GA24509@us.ibm.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-No-Spam-Score: Local Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Serge E. Hallyn wrote: > Quoting Alexey Dobriyan (adobriyan@gmail.com): > > Hi Alexey, > > as far as I can see, the main differences between this patch and the > equivalent in Oren's tree are: > > 1. kernel auto-selects container init to freeze Actually, this eliminates the possibility to checkpoint a subtree of tasks, which (under some obvious constraints) can be a handy feature. > 2. kernel freezes tasks IMHO better to do it in userspace - that way userspace can accomplish other tasks while tasks are frozen, such as snapshot the filesystem, or block/unblock the network. Is there a good argument to do it kernel ? > 3. no objhash taking references > 4. no hbuf > 5. always require CAP_SYS_ADMIN I'm now convinced (thanks, Serge!) that it's better not to require this unless we strictly have to. Oren.