* [patch 1/2] Add clone_child control file
2009-12-28 23:04 [patch 0/2] Remove the ns_cgroup Daniel Lezcano
@ 2009-12-28 23:04 ` Daniel Lezcano
[not found] ` <20091228230620.494084022-7Ha4D/yM3XKqUVqbrEjtMkN0fxke0PB7qyM6JfAXOaQ@public.gmane.org>
2009-12-28 23:04 ` [patch 2/2] Remove the ns_cgroup Daniel Lezcano
1 sibling, 1 reply; 7+ messages in thread
From: Daniel Lezcano @ 2009-12-28 23:04 UTC (permalink / raw)
To: containers-qjLDD68F18O7TbgM5vRIOg; +Cc: Paul Menage, Eric W. Biederman
[-- Attachment #1: cgroup-clone-parent.patch --]
[-- Type: text/plain, Size: 4066 bytes --]
This patch is sent as an answer to a previous thread around the ns_cgroup.
https://lists.linux-foundation.org/pipermail/containers/2009-June/018627.html
It adds a control file 'clone_children' for a cgroup.
This control file is a boolean specifying if the child cgroup should
be a clone of the parent cgroup or not. The default value is 'false'.
This flag makes the child cgroup to call the post_clone callback of all
the subsystem, if it is available.
At present, the cpuset is the only one which had implemented the post_clone
callback.
Signed-off-by: Daniel Lezcano <daniel.lezcano-GANU6spQydw@public.gmane.org>
Cc: Paul Menage <menage-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: Serge E. Hallyn <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
---
Documentation/cgroups/cgroups.txt | 14 ++++++++++++--
include/linux/cgroup.h | 4 ++++
kernel/cgroup.c | 26 ++++++++++++++++++++++++++
3 files changed, 42 insertions(+), 2 deletions(-)
Index: linux-2.6/include/linux/cgroup.h
===================================================================
--- linux-2.6.orig/include/linux/cgroup.h
+++ linux-2.6/include/linux/cgroup.h
@@ -139,6 +139,10 @@ enum {
* A thread in rmdir() is wating for this cgroup.
*/
CGRP_WAIT_ON_RMDIR,
+ /*
+ * Clone cgroup values when creating a new child cgroup
+ */
+ CGRP_CLONE_CHILDREN,
};
/* which pidlist file are we talking about? */
Index: linux-2.6/kernel/cgroup.c
===================================================================
--- linux-2.6.orig/kernel/cgroup.c
+++ linux-2.6/kernel/cgroup.c
@@ -2789,6 +2789,23 @@ static int cgroup_write_notify_on_releas
return 0;
}
+static u64 cgroup_clone_children_read(struct cgroup *cgrp,
+ struct cftype *cft)
+{
+ return test_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
+}
+
+static int cgroup_clone_children_write(struct cgroup *cgrp,
+ struct cftype *cft,
+ u64 val)
+{
+ if (val)
+ set_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
+ else
+ clear_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
+ return 0;
+}
+
/*
* for the common functions, 'private' gives the type of file
*/
@@ -2814,6 +2831,11 @@ static struct cftype files[] = {
.read_u64 = cgroup_read_notify_on_release,
.write_u64 = cgroup_write_notify_on_release,
},
+ {
+ .name = "clone_children",
+ .read_u64 = cgroup_clone_children_read,
+ .write_u64 = cgroup_clone_children_write,
+ },
};
static struct cftype cft_release_agent = {
@@ -2946,6 +2968,10 @@ static long cgroup_create(struct cgroup
if (alloc_css_id(ss, parent, cgrp))
goto err_destroy;
/* At error, ->destroy() callback has to free assigned ID. */
+
+ if (test_bit(CGRP_CLONE_CHILDREN, &parent->flags))
+ if (ss->post_clone)
+ ss->post_clone(ss, cgrp);
}
cgroup_lock_hierarchy(root);
Index: linux-2.6/Documentation/cgroups/cgroups.txt
===================================================================
--- linux-2.6.orig/Documentation/cgroups/cgroups.txt
+++ linux-2.6/Documentation/cgroups/cgroups.txt
@@ -18,7 +18,8 @@ CONTENTS:
1.2 Why are cgroups needed ?
1.3 How are cgroups implemented ?
1.4 What does notify_on_release do ?
- 1.5 How do I use cgroups ?
+ 1.5 What does clone_children do ?
+ 1.6 How do I use cgroups ?
2. Usage Examples and Syntax
2.1 Basic Usage
2.2 Attaching processes
@@ -292,7 +293,16 @@ notify_on_release in the root cgroup at
value of their parents notify_on_release setting. The default value of
a cgroup hierarchy's release_agent path is empty.
-1.5 How do I use cgroups ?
+1.5 What does clone_children do ?
+---------------------------------
+
+If the clone_children flag is enabled (1) in a cgroup, then all
+cgroups created beneath will call the post_clone callbacks for each
+subsystem of the newly created cgroup. Usually when this callback is
+implemented for a subsystem, it copies the values of the parent
+subsystem, this is the case for the cpuset.
+
+1.6 How do I use cgroups ?
--------------------------
To start a new job that is to be contained within a cgroup, using
^ permalink raw reply [flat|nested] 7+ messages in thread* [patch 2/2] Remove the ns_cgroup
2009-12-28 23:04 [patch 0/2] Remove the ns_cgroup Daniel Lezcano
2009-12-28 23:04 ` [patch 1/2] Add clone_child control file Daniel Lezcano
@ 2009-12-28 23:04 ` Daniel Lezcano
[not found] ` <20091228230623.907397717-7Ha4D/yM3XKqUVqbrEjtMkN0fxke0PB7qyM6JfAXOaQ@public.gmane.org>
1 sibling, 1 reply; 7+ messages in thread
From: Daniel Lezcano @ 2009-12-28 23:04 UTC (permalink / raw)
To: containers-qjLDD68F18O7TbgM5vRIOg; +Cc: Paul Menage, Eric W. Biederman
[-- Attachment #1: remove-ns-cgroup.patch --]
[-- Type: text/plain, Size: 12361 bytes --]
The ns_cgroup is an annoying cgroup at the namespace / cgroup frontier.
For example, a single process can not handle a big amount of namespaces
without interacting with this cgroup and falling in an exponential creation
time due to the nested cgroup directory depth (eg. /cgroup/<pid>/.../<pid>/...).
That was spotted when creating a single process using multiple network namespaces,
the objective was 4096 network namespaces, but at 820 netns, the creation time
was dramatically slow and the creation time for a namespace increased from 10msec
to 10sec. After five hours, the expected numbers of netns was not reached.
Without the ns_cgroup interaction, 4K netns are created after 2 minutes.
In order to solve that, we have to mount the cgroup with all the subsystems
except the ns_cgroup, it's a little weird and hard to manage from an administration
pov because we have to know what are the cgroup available on the system and we
can't do a simple 'mount -t cgroup cgroup /cgroup'.
With the previous patch which adds a 'clone_child' parameter to a cgroup,
we should be able to remove the ns_cgroup and manage manually the creation +
adding a task to the cgroup consistenly with the rest of the subsystems.
This patch removes the ns_cgroup as suggested in the following thread:
https://lists.linux-foundation.org/pipermail/containers/2009-June/018616.html
The 'cgroup_clone' function is removed because it is no longer used.
All the ns_cgroup.c code is removed, so we don't have the rules for attaching
a task to a cgroup, but I am not sure it's really relevant. Because we must have
the CAP_SYS_ADMIN for unsharing a namespace or to create a cgroup. Concerning
cgroup hierarchy vs process attachment I am not sure to understand what is the
goal of these checks and what are they for.
Signed-off-by: Daniel Lezcano <dlezcano-GANU6spQydw@public.gmane.org>
Cc: Eric W. Biederman <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
Cc: Paul Menage <menage-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: Serge E. Hallyn <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
Cc: Jamal Hadi Salim <hadi-fAAogVwAN2Kw5LPnMra/2Q@public.gmane.org>
---
include/linux/cgroup.h | 3 -
include/linux/cgroup_subsys.h | 6 --
init/Kconfig | 9 ---
kernel/Makefile | 1
kernel/cgroup.c | 116 ------------------------------------------
kernel/fork.c | 6 --
kernel/ns_cgroup.c | 110 ---------------------------------------
kernel/nsproxy.c | 15 +----
8 files changed, 3 insertions(+), 263 deletions(-)
Index: linux-2.6/include/linux/cgroup.h
===================================================================
--- linux-2.6.orig/include/linux/cgroup.h
+++ linux-2.6/include/linux/cgroup.h
@@ -499,9 +499,6 @@ static inline struct cgroup* task_cgroup
return task_subsys_state(task, subsys_id)->cgroup;
}
-int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *ss,
- char *nodename);
-
/* A cgroup_iter should be treated as an opaque object */
struct cgroup_iter {
struct list_head *cg_link;
Index: linux-2.6/init/Kconfig
===================================================================
--- linux-2.6.orig/init/Kconfig
+++ linux-2.6/init/Kconfig
@@ -512,15 +512,6 @@ config CGROUP_DEBUG
Say N if unsure.
-config CGROUP_NS
- bool "Namespace cgroup subsystem"
- depends on CGROUPS
- help
- Provides a simple namespace cgroup subsystem to
- provide hierarchical naming of sets of namespaces,
- for instance virtual servers and checkpoint/restart
- jobs.
-
config CGROUP_FREEZER
bool "Freezer cgroup subsystem"
depends on CGROUPS
Index: linux-2.6/kernel/Makefile
===================================================================
--- linux-2.6.orig/kernel/Makefile
+++ linux-2.6/kernel/Makefile
@@ -61,7 +61,6 @@ obj-$(CONFIG_COMPAT) += compat.o
obj-$(CONFIG_CGROUPS) += cgroup.o
obj-$(CONFIG_CGROUP_FREEZER) += cgroup_freezer.o
obj-$(CONFIG_CPUSETS) += cpuset.o
-obj-$(CONFIG_CGROUP_NS) += ns_cgroup.o
obj-$(CONFIG_UTS_NS) += utsname.o
obj-$(CONFIG_USER_NS) += user_namespace.o
obj-$(CONFIG_PID_NS) += pid_namespace.o
Index: linux-2.6/kernel/cgroup.c
===================================================================
--- linux-2.6.orig/kernel/cgroup.c
+++ linux-2.6/kernel/cgroup.c
@@ -3564,122 +3564,6 @@ void cgroup_exit(struct task_struct *tsk
}
/**
- * cgroup_clone - clone the cgroup the given subsystem is attached to
- * @tsk: the task to be moved
- * @subsys: the given subsystem
- * @nodename: the name for the new cgroup
- *
- * Duplicate the current cgroup in the hierarchy that the given
- * subsystem is attached to, and move this task into the new
- * child.
- */
-int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
- char *nodename)
-{
- struct dentry *dentry;
- int ret = 0;
- struct cgroup *parent, *child;
- struct inode *inode;
- struct css_set *cg;
- struct cgroupfs_root *root;
- struct cgroup_subsys *ss;
-
- /* We shouldn't be called by an unregistered subsystem */
- BUG_ON(!subsys->active);
-
- /* First figure out what hierarchy and cgroup we're dealing
- * with, and pin them so we can drop cgroup_mutex */
- mutex_lock(&cgroup_mutex);
- again:
- root = subsys->root;
- if (root == &rootnode) {
- mutex_unlock(&cgroup_mutex);
- return 0;
- }
-
- /* Pin the hierarchy */
- if (!atomic_inc_not_zero(&root->sb->s_active)) {
- /* We race with the final deactivate_super() */
- mutex_unlock(&cgroup_mutex);
- return 0;
- }
-
- /* Keep the cgroup alive */
- task_lock(tsk);
- parent = task_cgroup(tsk, subsys->subsys_id);
- cg = tsk->cgroups;
- get_css_set(cg);
- task_unlock(tsk);
-
- mutex_unlock(&cgroup_mutex);
-
- /* Now do the VFS work to create a cgroup */
- inode = parent->dentry->d_inode;
-
- /* Hold the parent directory mutex across this operation to
- * stop anyone else deleting the new cgroup */
- mutex_lock(&inode->i_mutex);
- dentry = lookup_one_len(nodename, parent->dentry, strlen(nodename));
- if (IS_ERR(dentry)) {
- printk(KERN_INFO
- "cgroup: Couldn't allocate dentry for %s: %ld\n", nodename,
- PTR_ERR(dentry));
- ret = PTR_ERR(dentry);
- goto out_release;
- }
-
- /* Create the cgroup directory, which also creates the cgroup */
- ret = vfs_mkdir(inode, dentry, 0755);
- child = __d_cgrp(dentry);
- dput(dentry);
- if (ret) {
- printk(KERN_INFO
- "Failed to create cgroup %s: %d\n", nodename,
- ret);
- goto out_release;
- }
-
- /* The cgroup now exists. Retake cgroup_mutex and check
- * that we're still in the same state that we thought we
- * were. */
- mutex_lock(&cgroup_mutex);
- if ((root != subsys->root) ||
- (parent != task_cgroup(tsk, subsys->subsys_id))) {
- /* Aargh, we raced ... */
- mutex_unlock(&inode->i_mutex);
- put_css_set(cg);
-
- deactivate_super(root->sb);
- /* The cgroup is still accessible in the VFS, but
- * we're not going to try to rmdir() it at this
- * point. */
- printk(KERN_INFO
- "Race in cgroup_clone() - leaking cgroup %s\n",
- nodename);
- goto again;
- }
-
- /* do any required auto-setup */
- for_each_subsys(root, ss) {
- if (ss->post_clone)
- ss->post_clone(ss, child);
- }
-
- /* All seems fine. Finish by moving the task into the new cgroup */
- ret = cgroup_attach_task(child, tsk);
- mutex_unlock(&cgroup_mutex);
-
- out_release:
- mutex_unlock(&inode->i_mutex);
-
- mutex_lock(&cgroup_mutex);
- put_css_set(cg);
- mutex_unlock(&cgroup_mutex);
- deactivate_super(root->sb);
- return ret;
-}
-
-/**
* cgroup_is_descendant - see if @cgrp is a descendant of @task's cgrp
* @cgrp: the cgroup in question
* @task: the task in question
Index: linux-2.6/kernel/fork.c
===================================================================
--- linux-2.6.orig/kernel/fork.c
+++ linux-2.6/kernel/fork.c
@@ -1184,12 +1184,6 @@ static struct task_struct *copy_process(
if (clone_flags & CLONE_THREAD)
p->tgid = current->tgid;
- if (current->nsproxy != p->nsproxy) {
- retval = ns_cgroup_clone(p, pid);
- if (retval)
- goto bad_fork_free_pid;
- }
-
p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
/*
* Clear TID on mm_release()?
Index: linux-2.6/kernel/ns_cgroup.c
===================================================================
--- linux-2.6.orig/kernel/ns_cgroup.c
+++ /dev/null
@@ -1,110 +0,0 @@
-/*
- * ns_cgroup.c - namespace cgroup subsystem
- *
- * Copyright 2006, 2007 IBM Corp
- */
-
-#include <linux/module.h>
-#include <linux/cgroup.h>
-#include <linux/fs.h>
-#include <linux/proc_fs.h>
-#include <linux/slab.h>
-#include <linux/nsproxy.h>
-
-struct ns_cgroup {
- struct cgroup_subsys_state css;
-};
-
-struct cgroup_subsys ns_subsys;
-
-static inline struct ns_cgroup *cgroup_to_ns(
- struct cgroup *cgroup)
-{
- return container_of(cgroup_subsys_state(cgroup, ns_subsys_id),
- struct ns_cgroup, css);
-}
-
-int ns_cgroup_clone(struct task_struct *task, struct pid *pid)
-{
- char name[PROC_NUMBUF];
-
- snprintf(name, PROC_NUMBUF, "%d", pid_vnr(pid));
- return cgroup_clone(task, &ns_subsys, name);
-}
-
-/*
- * Rules:
- * 1. you can only enter a cgroup which is a descendant of your current
- * cgroup
- * 2. you can only place another process into a cgroup if
- * a. you have CAP_SYS_ADMIN
- * b. your cgroup is an ancestor of task's destination cgroup
- * (hence either you are in the same cgroup as task, or in an
- * ancestor cgroup thereof)
- */
-static int ns_can_attach(struct cgroup_subsys *ss, struct cgroup *new_cgroup,
- struct task_struct *task, bool threadgroup)
-{
- if (current != task) {
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
- if (!cgroup_is_descendant(new_cgroup, current))
- return -EPERM;
- }
-
- if (!cgroup_is_descendant(new_cgroup, task))
- return -EPERM;
-
- if (threadgroup) {
- struct task_struct *c;
- rcu_read_lock();
- list_for_each_entry_rcu(c, &task->thread_group, thread_group) {
- if (!cgroup_is_descendant(new_cgroup, c)) {
- rcu_read_unlock();
- return -EPERM;
- }
- }
- rcu_read_unlock();
- }
-
- return 0;
-}
-
-/*
- * Rules: you can only create a cgroup if
- * 1. you are capable(CAP_SYS_ADMIN)
- * 2. the target cgroup is a descendant of your own cgroup
- */
-static struct cgroup_subsys_state *ns_create(struct cgroup_subsys *ss,
- struct cgroup *cgroup)
-{
- struct ns_cgroup *ns_cgroup;
-
- if (!capable(CAP_SYS_ADMIN))
- return ERR_PTR(-EPERM);
- if (!cgroup_is_descendant(cgroup, current))
- return ERR_PTR(-EPERM);
-
- ns_cgroup = kzalloc(sizeof(*ns_cgroup), GFP_KERNEL);
- if (!ns_cgroup)
- return ERR_PTR(-ENOMEM);
- return &ns_cgroup->css;
-}
-
-static void ns_destroy(struct cgroup_subsys *ss,
- struct cgroup *cgroup)
-{
- struct ns_cgroup *ns_cgroup;
-
- ns_cgroup = cgroup_to_ns(cgroup);
- kfree(ns_cgroup);
-}
-
-struct cgroup_subsys ns_subsys = {
- .name = "ns",
- .can_attach = ns_can_attach,
- .create = ns_create,
- .destroy = ns_destroy,
- .subsys_id = ns_subsys_id,
-};
Index: linux-2.6/kernel/nsproxy.c
===================================================================
--- linux-2.6.orig/kernel/nsproxy.c
+++ linux-2.6/kernel/nsproxy.c
@@ -170,8 +170,6 @@ void free_nsproxy(struct nsproxy *ns)
int unshare_nsproxy_namespaces(unsigned long unshare_flags,
struct nsproxy **new_nsp, struct fs_struct *new_fs)
{
- int err = 0;
-
if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
CLONE_NEWNET)))
return 0;
@@ -181,17 +179,10 @@ int unshare_nsproxy_namespaces(unsigned
*new_nsp = create_new_namespaces(unshare_flags, current,
new_fs ? new_fs : current->fs);
- if (IS_ERR(*new_nsp)) {
- err = PTR_ERR(*new_nsp);
- goto out;
- }
+ if (IS_ERR(*new_nsp))
+ return PTR_ERR(*new_nsp);
- err = ns_cgroup_clone(current, task_pid(current));
- if (err)
- put_nsproxy(*new_nsp);
-
-out:
- return err;
+ return 0;
}
void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
Index: linux-2.6/include/linux/cgroup_subsys.h
===================================================================
--- linux-2.6.orig/include/linux/cgroup_subsys.h
+++ linux-2.6/include/linux/cgroup_subsys.h
@@ -19,12 +19,6 @@ SUBSYS(debug)
/* */
-#ifdef CONFIG_CGROUP_NS
-SUBSYS(ns)
-#endif
-
-/* */
-
#ifdef CONFIG_CGROUP_SCHED
SUBSYS(cpu_cgroup)
#endif
^ permalink raw reply [flat|nested] 7+ messages in thread