Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752646AbZI3Feq (ORCPT ); Wed, 30 Sep 2009 01:34:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751905AbZI3Fep (ORCPT ); Wed, 30 Sep 2009 01:34:45 -0400 Received: from mail-ew0-f211.google.com ([209.85.219.211]:56741 "EHLO mail-ew0-f211.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751536AbZI3Fep (ORCPT ); Wed, 30 Sep 2009 01:34:45 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=w9wryQlqjmNFo01W42W3q8TYKsku+SXz1jwZTukS6lPnSJWy16k6dmwIW8WbWP4idb +VFQ3eBKJJvycRO4BHzCfeZeJjRtvHmrPus4+YPcUtO2Ba7bH9nMkwfVAY7AIB8nKxL1 k7T+5xmyDXIOkA2Lduqvjpqlbyg5QCN1wY3oE= Date: Wed, 30 Sep 2009 09:34:43 +0400 From: Alexey Dobriyan To: "Serge E. Hallyn" Cc: Sukadev Bhattiprolu , linux-kernel@vger.kernel.org, Oren Laadan , "Eric W. Biederman" , Pavel Emelyanov , Andrew Morton , torvalds@linux-foundation.org, mikew@google.com, mingo@elte.hu, hpa@zytor.com, Nathan Lynch , arnd@arndb.de, peterz@infradead.org, Containers , sukadev@us.ibm.com Subject: Re: [RFC][v7][PATCH 0/9] Implement clone2() system call Message-ID: <20090930053443.GA1010@x200> References: <20090924165548.GA16586@us.ibm.com> <20090924175542.GA27678@x200> <20090924183556.GA31356@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090924183556.GA31356@us.ibm.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1660 Lines: 33 On Thu, Sep 24, 2009 at 01:35:56PM -0500, Serge E. Hallyn wrote: > Quoting Alexey Dobriyan (adobriyan@gmail.com): > > I don't like this even more. > > > > Pid namespaces are hierarchical _and_ anonymous, so simply > > set of numbers doesn't describe the final object. > > > > struct pid isn't special, it's just another invariant if you like > > as far as C/R is concerned, but system call is made special wrt pids. > > > > What will be in an image? I hope "struct kstate_image_pid" with several > > Sure pid namespaces are anonymous, but we will give each an 'objref' > valid only for a checkpoint image, and store the relationship between > pid namespaces based on those objrefs. Basically the same way that user > structs and hierarchical user namespaces are handled right now. OK, that's certainly doable. You're commiting yourself to creation of tasks in userspace if this goes in. :-\ Which can let you into putting wrong kind of relations into image. IIRC, clone_flags were in image (still?), but tomorrow kernel will get new way to acquire, say, uts_ns, which, in theory, can't be described by a set of consecutive clones, so, you'll have to fixup something in kernel. > > numbers and with references to such object from other places, so it > > seems natural to do alloc_pid() with needed numbers and that attach new > > shiny pid to where needed. But this clone_pid is only for task_struct's pids. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/