From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH 0/3] clone64() and unshare64() system calls Date: Wed, 09 Apr 2008 17:00:25 -0700 Message-ID: <47FD5899.2040206@zytor.com> References: <20080409222611.GA28087@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20080409222611.GA28087-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: sukadev-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org Cc: "David C. Hansen" , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org, Containers , Pavel Emelyanov List-Id: containers.vger.kernel.org sukadev-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org wrote: > This is a resend of the patch set Cedric had sent earlier. I ported > the patch set to 2.6.25-rc8-mm1 and tested on x86 and x86_64. > --- > > We have run out of the 32 bits in clone_flags ! > > This patchset introduces 2 new system calls which support 64bit clone-flags. > > long sys_clone64(unsigned long flags_high, unsigned long flags_low, > unsigned long newsp); > > long sys_unshare64(unsigned long flags_high, unsigned long flags_low); > > The current version of clone64() does not support CLONE_PARENT_SETTID and > CLONE_CHILD_CLEARTID because we would exceed the 6 registers limit of some > arches. It's possible to get around this limitation but we might not > need it as we already have clone() > I really dislike this interface. If you're going to make it a 64-bit pass it in as a 64-bit number, instead of breaking it into two numbers. Better yet, IMO, would be to pass a pointer to a structure like: struct shared { unsigned long nwords; unsigned long flags[]; }; ... which can be expanded indefinitely. -hpa