From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Emelyanov Subject: Re: [PATCH 14/20] Allow cloning of new namespace Date: Wed, 08 Aug 2007 11:29:59 +0400 Message-ID: <46B970F7.3070200@openvz.org> References: <46B83B9A.mailG5N11PRTB@openvz.org> <20070807224827.GA2375@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20070807224827.GA2375-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: containers-qjLDD68F18O7TbgM5vRIOg@public.gmane.org, oleg-6lXkIZvqkOAvJsYlp49lxw@public.gmane.org List-Id: containers.vger.kernel.org sukadev-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org wrote: > Pavel Emelianov [xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org] wrote: > | When clone() is invoked with CLONE_NEWPID, create a new pid namespace > | and then create a new struct pid for the new process. Allocate pid_t's > | for the new process in the new pid namespace and all ancestor pid > | namespaces. Make the newly cloned process the session and process group > | leader. > | > | Since the active pid namespace is special and expected to be the first > > active pid ns is the *last entry* in this patchset (not first) right ? yes. thanks. > | entry in pid->upid_list, preserve the order of pid namespaces. > | > | The size of 'struct pid' is dependent on the the number of pid namespaces > | the process exists in, so we use multiple pid-caches'. Only one pid cache > | is created during system startup and this used by processes that exist > | only in init_pid_ns. > | > | When a process clones its pid namespace, we create additional pid caches > | as necessary and use the pid cache to allocate 'struct pids' for that depth. > | > | Note, that with this patch the newly created namespace won't work, since > | the rest of the kernel still uses global pids, but this is to be fixed > | soon. Init pid namespace still works. > | > | Signed-off-by: Pavel Emelyanov > | Signed-off-by: Sukadev Bhattiprolu > | > | --- > | > | include/linux/sched.h | 1 > | kernel/fork.c | 48 +++++++++++++++++--------- > | kernel/nsproxy.c | 3 + > | kernel/pid.c | 91 +++++++++++++++++++++++++++++++++++++++++++++----- > | 4 files changed, 118 insertions(+), 25 deletions(-) > | > | --- ./include/linux/sched.h.ve14 2007-08-06 15:00:09.000000000 +0400 > | +++ ./include/linux/sched.h 2007-08-06 15:00:09.000000000 +0400 > | @@ -27,6 +27,7 @@ > | #define CLONE_NEWUTS 0x04000000 /* New utsname group? */ > | #define CLONE_NEWIPC 0x08000000 /* New ipcs */ > | #define CLONE_NEWUSER 0x10000000 /* New user namespace */ > | +#define CLONE_NEWPID 0x20000000 /* New pids */ > > Nit. I think "New pid namespace" would be a better comment. ok. > Suka > Thanks, Pavel