[Devel] Re: [RFC][PATCH 1/5] Virtualization/containers: startup

[Hubertus Franke]

missed the typedef on container ..
I am still on 2.6.15.2

> Couple of minor naming nitpick questions, though.  Is vps/container_info
> really what we want to call it?  It seems to me to be the basis for a
> real "container", without the _info part.
> 
> "tsk->owner_container"  That makes it sound like a pointer to the "task
> owner's container".  How about "owning_container"?  The "container
> owning this task".  Or, maybe just "container"?
> 
> Any particular reason for the "u32 id" in the vps_info struct as opposed
> to one of the more generic types?  Do we want to abstract this one in
> the same way we do pid_t?
> 
> The "host" in "host_container_info" doesn't mean much to me.  Though, I
> guess it has some context in the UML space.  Would "init_container_info"
> or "root_container_info" be more descriptive?
> 
> Lastly, is this a place for krefs?  I don't see a real need for a
> destructor yet, but the idea is fresh in my mind.
> 
> How does the attached patch look?

here is that adapted ....

Index: linux-2.6.15/include/linux/container.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.15/include/linux/container.h	2006-02-03 14:52:12.000000000
-0500
@@ -0,0 +1,42 @@
+#ifndef __LINUX_CONTAINER_H_
+#define __LINUX_CONTAINER_H_
+
+#include <asm/types.h>
+#include <asm/atomic.h>
+
+struct task_struct;
+
+struct container {
+	u32 id;
+	struct task_struct *init_task;
+	atomic_t refcnt;
+};
+
+extern struct container root_container;
+
+static inline struct container*
+get_container(struct container *container)
+{
+	atomic_inc(&container->refcnt);
+	return container;
+}
+
+static inline void put_container(struct container *container)
+{
+	atomic_dec(&container->refcnt);
+}
+
+#include <linux/sched.h>
+#include <asm/current.h>
+
+static inline struct container*
+set_current_container(struct container *container)
+{
+	struct container *ret;
+
+	ret = current->container;
+	current->container = container;
+	return ret;
+}
+
+#endif
Index: linux-2.6.15/include/linux/init_task.h
===================================================================
--- linux-2.6.15.orig/include/linux/init_task.h	2006-02-03
14:50:39.000000000 -0500
+++ linux-2.6.15/include/linux/init_task.h	2006-02-03 14:52:12.000000000
-0500
@@ -3,6 +3,7 @@
 
 #include <linux/file.h>
 #include <linux/rcupdate.h>
+#include <linux/container.h>
 
 #define INIT_FDTABLE \
 {							\
@@ -121,6 +122,7 @@ extern struct group_info init_groups;
 	.journal_info	= NULL,						\
 	.cpu_timers	= INIT_CPU_TIMERS(tsk.cpu_timers),		\
 	.fs_excl	= ATOMIC_INIT(0),				\
+	.container = &root_container,				\
 }
 
 
Index: linux-2.6.15/include/linux/sched.h
===================================================================
--- linux-2.6.15.orig/include/linux/sched.h	2006-02-03
14:50:39.000000000 -0500
+++ linux-2.6.15/include/linux/sched.h	2006-02-03 14:52:12.000000000
-0500
@@ -682,6 +682,7 @@ static inline void prefetch_stack(struct
 
 struct audit_context;		/* See audit.c */
 struct mempolicy;
+struct container;
 
 struct task_struct {
 	volatile long state;	/* -1 unrunnable, 0 runnable, >0 stopped */
@@ -830,6 +831,7 @@ struct task_struct {
 	struct backing_dev_info *backing_dev_info;
 
 	struct io_context *io_context;
+	struct container *container;
 
 	unsigned long ptrace_message;
 	siginfo_t *last_siginfo; /* For ptrace use.  */
@@ -859,6 +861,8 @@ struct task_struct {
 	atomic_t fs_excl;	/* holding fs exclusive resources */
 };
 
+#define current_container()	(current->container)
+
 static inline pid_t process_group(struct task_struct *tsk)
 {
 	return tsk->signal->pgrp;
Index: linux-2.6.15/init/main.c
===================================================================
--- linux-2.6.15.orig/init/main.c	2006-02-03 14:50:39.000000000 -0500
+++ linux-2.6.15/init/main.c	2006-02-03 14:52:12.000000000 -0500
@@ -47,8 +47,8 @@
 #include <linux/rmap.h>
 #include <linux/mempolicy.h>
 #include <linux/key.h>
+#include <linux/container.h>
 #include <net/sock.h>
-
 #include <asm/io.h>
 #include <asm/bugs.h>
 #include <asm/setup.h>
@@ -438,6 +438,13 @@ void __init parse_early_param(void)
 	done = 1;
 }
 
+struct container root_container = {
+	.id		= 0,
+	.init_task	= &init_task,
+	.refcnt		= ATOMIC_INIT(1),
+};
+
+EXPORT_SYMBOL(root_container);
 /*
  *	Activate the first processor.
  */
Index: linux-2.6.15/kernel/exit.c
===================================================================
--- linux-2.6.15.orig/kernel/exit.c	2006-02-03 14:50:39.000000000 -0500
+++ linux-2.6.15/kernel/exit.c	2006-02-03 14:52:12.000000000 -0500
@@ -29,6 +29,7 @@
 #include <linux/syscalls.h>
 #include <linux/signal.h>
 #include <linux/cn_proc.h>
+#include <linux/container.h>
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -106,6 +107,7 @@ repeat: 
 	spin_unlock(&p->proc_lock);
 	proc_pid_flush(proc_dentry);
 	release_thread(p);
+	put_container(p->container);
 	put_task_struct(p);
 
 	p = leader;
Index: linux-2.6.15/kernel/fork.c
===================================================================
--- linux-2.6.15.orig/kernel/fork.c	2006-02-03 14:50:39.000000000 -0500
+++ linux-2.6.15/kernel/fork.c	2006-02-03 14:52:12.000000000 -0500
@@ -43,6 +43,7 @@
 #include <linux/rmap.h>
 #include <linux/acct.h>
 #include <linux/cn_proc.h>
+#include <linux/container.h>
 
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
@@ -1121,6 +1122,7 @@ static task_t *copy_process(unsigned lon
 	p->ioprio = current->ioprio;
 
 	SET_LINKS(p);
+	get_container(p->container);
 	if (unlikely(p->ptrace & PT_PTRACED))
 		__ptrace_link(p, current->parent);