Re: [PATCH 3/3] cgroup : remove the ns_cgroup

From: Matt Helsley
Date: Thu Jul 29 2010 - 17:40:27 EST

On Thu, Jul 29, 2010 at 02:58:12PM -0500, Serge E. Hallyn wrote:
> 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.

Is this problem related to Andrew's post here re:

[Bugme-new] [Bug 16417] New: Slow context switches with SMP and CONFIG_FAIR_GROUP_SCHED

>
> 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_children' 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.
>
> Changelog: Jul 29 (seh): remove references to ns_cgroup_clone(), fix up
> some documentation, and remove CONFIG_CGROUP_NS references.
>
> Signed-off-by: Daniel Lezcano <dlezcano@xxxxxxx>
> Signed-off-by: Serge E. Hallyn <serge.hallyn@xxxxxxxxxxxxx>
> Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
> Cc: Paul Menage <menage@xxxxxxxxxx>
> Cc: Jamal Hadi Salim <hadi@xxxxxxxxxx>

Good riddance to cgroup_clone(). I seem to recall it required some
fairly nasty code contortions and only the ns cgroup needed/used it.

Acked-by: Matt Helsley <matthltc@xxxxxxxxxx>

> ---
> Documentation/cgroups/cgroups.txt | 2 +-
> arch/ia64/configs/generic_defconfig | 1 -
> arch/mips/configs/bcm47xx_defconfig | 1 -
> arch/mips/configs/ip27_defconfig | 1 -
> arch/mips/configs/sb1250-swarm_defconfig | 1 -
> arch/powerpc/configs/cell_defconfig | 1 -
> arch/powerpc/configs/ppc64_defconfig | 1 -
> arch/powerpc/configs/ppc64e_defconfig | 1 -
> arch/powerpc/configs/ppc6xx_defconfig | 1 -
> arch/powerpc/configs/pseries_defconfig | 1 -
> arch/s390/defconfig | 1 -
> arch/sh/configs/sdk7786_defconfig | 1 -
> arch/sh/configs/se7206_defconfig | 1 -
> arch/sh/configs/sh7724_generic_defconfig | 1 -
> arch/sh/configs/sh7770_generic_defconfig | 1 -
> arch/sh/configs/shx3_defconfig | 1 -
> arch/sh/configs/urquell_defconfig | 1 -
> arch/x86/configs/i386_defconfig | 1 -
> arch/x86/configs/x86_64_defconfig | 1 -
> include/linux/cgroup.h | 3 -
> include/linux/cgroup_subsys.h | 6 --
> include/linux/nsproxy.h | 9 ---
> init/Kconfig | 9 ---
> kernel/Makefile | 1 -
> kernel/cgroup.c | 116 ------------------------------
> kernel/cpuset.c | 7 +-
> kernel/fork.c | 6 --
> kernel/ns_cgroup.c | 110 ----------------------------
> kernel/nsproxy.c | 4 -
> 29 files changed, 4 insertions(+), 287 deletions(-)
> delete mode 100644 kernel/ns_cgroup.c
>
> diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt
> index 190018b..6a5ba63 100644
> --- a/Documentation/cgroups/cgroups.txt
> +++ b/Documentation/cgroups/cgroups.txt
> @@ -618,7 +618,7 @@ always handled well.
> void post_clone(struct cgroup_subsys *ss, struct cgroup *cgrp)
> (cgroup_mutex held by caller)
>
> -Called at the end of cgroup_clone() to do any parameter
> +Called during cgroup_create() to do any parameter
> initialization which might be required before a task could attach. For
> example in cpusets, no task may attach before 'cpus' and 'mems' are set
> up.
> diff --git a/arch/ia64/configs/generic_defconfig b/arch/ia64/configs/generic_defconfig
> index 6a4cc50..d257546 100644
> --- a/arch/ia64/configs/generic_defconfig
> +++ b/arch/ia64/configs/generic_defconfig
> @@ -25,7 +25,6 @@ CONFIG_IKCONFIG_PROC=y
> CONFIG_LOG_BUF_SHIFT=20
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> -# CONFIG_CGROUP_NS is not set
> # CONFIG_CGROUP_FREEZER is not set
> # CONFIG_CGROUP_DEVICE is not set
> CONFIG_CPUSETS=y
> diff --git a/arch/mips/configs/bcm47xx_defconfig b/arch/mips/configs/bcm47xx_defconfig
> index bbd826b..cb75ade 100644
> --- a/arch/mips/configs/bcm47xx_defconfig
> +++ b/arch/mips/configs/bcm47xx_defconfig
> @@ -199,7 +199,6 @@ CONFIG_TINY_RCU=y
> CONFIG_LOG_BUF_SHIFT=17
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> -CONFIG_CGROUP_NS=y
> # CONFIG_CGROUP_FREEZER is not set
> # CONFIG_CGROUP_DEVICE is not set
> # CONFIG_CPUSETS is not set
> diff --git a/arch/mips/configs/ip27_defconfig b/arch/mips/configs/ip27_defconfig
> index 84b6503..036ad3e 100644
> --- a/arch/mips/configs/ip27_defconfig
> +++ b/arch/mips/configs/ip27_defconfig
> @@ -209,7 +209,6 @@ CONFIG_LOG_BUF_SHIFT=15
> # CONFIG_GROUP_SCHED is not set
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> -# CONFIG_CGROUP_NS is not set
> # CONFIG_CGROUP_FREEZER is not set
> # CONFIG_CGROUP_DEVICE is not set
> CONFIG_CPUSETS=y
> diff --git a/arch/mips/configs/sb1250-swarm_defconfig b/arch/mips/configs/sb1250-swarm_defconfig
> index 7f07bf0..0f059f2 100644
> --- a/arch/mips/configs/sb1250-swarm_defconfig
> +++ b/arch/mips/configs/sb1250-swarm_defconfig
> @@ -197,7 +197,6 @@ CONFIG_SYSVIPC_SYSCTL=y
> CONFIG_LOG_BUF_SHIFT=15
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> -# CONFIG_CGROUP_NS is not set
> CONFIG_CPUSETS=y
> CONFIG_GROUP_SCHED=y
> CONFIG_FAIR_GROUP_SCHED=y
> diff --git a/arch/powerpc/configs/cell_defconfig b/arch/powerpc/configs/cell_defconfig
> index 9433719..cfa9177 100644
> --- a/arch/powerpc/configs/cell_defconfig
> +++ b/arch/powerpc/configs/cell_defconfig
> @@ -76,7 +76,6 @@ CONFIG_IKCONFIG_PROC=y
> CONFIG_LOG_BUF_SHIFT=15
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> -# CONFIG_CGROUP_NS is not set
> CONFIG_CPUSETS=y
> # CONFIG_GROUP_SCHED is not set
> # CONFIG_USER_SCHED is not set
> diff --git a/arch/powerpc/configs/ppc64_defconfig b/arch/powerpc/configs/ppc64_defconfig
> index 369f4e0..2bc8f44 100644
> --- a/arch/powerpc/configs/ppc64_defconfig
> +++ b/arch/powerpc/configs/ppc64_defconfig
> @@ -86,7 +86,6 @@ CONFIG_IKCONFIG_PROC=y
> CONFIG_LOG_BUF_SHIFT=17
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> -# CONFIG_CGROUP_NS is not set
> # CONFIG_CGROUP_FREEZER is not set
> # CONFIG_CGROUP_DEVICE is not set
> CONFIG_CPUSETS=y
> diff --git a/arch/powerpc/configs/ppc64e_defconfig b/arch/powerpc/configs/ppc64e_defconfig
> index 403e82e..ac0f13d 100644
> --- a/arch/powerpc/configs/ppc64e_defconfig
> +++ b/arch/powerpc/configs/ppc64e_defconfig
> @@ -100,7 +100,6 @@ CONFIG_LOG_BUF_SHIFT=17
> # CONFIG_GROUP_SCHED is not set
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> -# CONFIG_CGROUP_NS is not set
> # CONFIG_CGROUP_FREEZER is not set
> # CONFIG_CGROUP_DEVICE is not set
> CONFIG_CPUSETS=y
> diff --git a/arch/powerpc/configs/ppc6xx_defconfig b/arch/powerpc/configs/ppc6xx_defconfig
> index 12dc7c4..8175eba 100644
> --- a/arch/powerpc/configs/ppc6xx_defconfig
> +++ b/arch/powerpc/configs/ppc6xx_defconfig
> @@ -88,7 +88,6 @@ CONFIG_AUDIT_TREE=y
> CONFIG_LOG_BUF_SHIFT=17
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> -CONFIG_CGROUP_NS=y
> # CONFIG_CGROUP_FREEZER is not set
> CONFIG_CGROUP_DEVICE=y
> CONFIG_GROUP_SCHED=y
> diff --git a/arch/powerpc/configs/pseries_defconfig b/arch/powerpc/configs/pseries_defconfig
> index 16ae717..6d96b61 100644
> --- a/arch/powerpc/configs/pseries_defconfig
> +++ b/arch/powerpc/configs/pseries_defconfig
> @@ -85,7 +85,6 @@ CONFIG_IKCONFIG_PROC=y
> CONFIG_LOG_BUF_SHIFT=17
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> -CONFIG_CGROUP_NS=y
> CONFIG_CGROUP_FREEZER=y
> CONFIG_CGROUP_DEVICE=y
> CONFIG_CPUSETS=y
> diff --git a/arch/s390/defconfig b/arch/s390/defconfig
> index 253f158..08e9f82 100644
> --- a/arch/s390/defconfig
> +++ b/arch/s390/defconfig
> @@ -72,7 +72,6 @@ CONFIG_IKCONFIG_PROC=y
> CONFIG_LOG_BUF_SHIFT=17
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> -CONFIG_CGROUP_NS=y
> # CONFIG_CGROUP_FREEZER is not set
> # CONFIG_CGROUP_DEVICE is not set
> # CONFIG_CPUSETS is not set
> diff --git a/arch/sh/configs/sdk7786_defconfig b/arch/sh/configs/sdk7786_defconfig
> index 2698245..0f6894e 100644
> --- a/arch/sh/configs/sdk7786_defconfig
> +++ b/arch/sh/configs/sdk7786_defconfig
> @@ -84,7 +84,6 @@ CONFIG_IKCONFIG_PROC=y
> CONFIG_LOG_BUF_SHIFT=17
> CONFIG_CGROUPS=y
> CONFIG_CGROUP_DEBUG=y
> -CONFIG_CGROUP_NS=y
> CONFIG_CGROUP_FREEZER=y
> CONFIG_CGROUP_DEVICE=y
> CONFIG_CPUSETS=y
> diff --git a/arch/sh/configs/se7206_defconfig b/arch/sh/configs/se7206_defconfig
> index 910eaec..d2c0fc8 100644
> --- a/arch/sh/configs/se7206_defconfig
> +++ b/arch/sh/configs/se7206_defconfig
> @@ -77,7 +77,6 @@ CONFIG_TREE_RCU_TRACE=y
> CONFIG_LOG_BUF_SHIFT=14
> CONFIG_CGROUPS=y
> CONFIG_CGROUP_DEBUG=y
> -CONFIG_CGROUP_NS=y
> # CONFIG_CGROUP_FREEZER is not set
> CONFIG_CGROUP_DEVICE=y
> # CONFIG_CPUSETS is not set
> diff --git a/arch/sh/configs/sh7724_generic_defconfig b/arch/sh/configs/sh7724_generic_defconfig
> index a6a9e68..c3a2f67 100644
> --- a/arch/sh/configs/sh7724_generic_defconfig
> +++ b/arch/sh/configs/sh7724_generic_defconfig
> @@ -70,7 +70,6 @@ CONFIG_RCU_FANOUT=32
> CONFIG_LOG_BUF_SHIFT=17
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> -# CONFIG_CGROUP_NS is not set
> # CONFIG_CGROUP_FREEZER is not set
> # CONFIG_CGROUP_DEVICE is not set
> # CONFIG_CPUSETS is not set
> diff --git a/arch/sh/configs/sh7770_generic_defconfig b/arch/sh/configs/sh7770_generic_defconfig
> index 4327f89..ce2357f 100644
> --- a/arch/sh/configs/sh7770_generic_defconfig
> +++ b/arch/sh/configs/sh7770_generic_defconfig
> @@ -69,7 +69,6 @@ CONFIG_RCU_FANOUT=32
> CONFIG_LOG_BUF_SHIFT=17
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> -# CONFIG_CGROUP_NS is not set
> # CONFIG_CGROUP_FREEZER is not set
> # CONFIG_CGROUP_DEVICE is not set
> # CONFIG_CPUSETS is not set
> diff --git a/arch/sh/configs/shx3_defconfig b/arch/sh/configs/shx3_defconfig
> index 42f6bd3..05ced6a 100644
> --- a/arch/sh/configs/shx3_defconfig
> +++ b/arch/sh/configs/shx3_defconfig
> @@ -84,7 +84,6 @@ CONFIG_IKCONFIG_PROC=y
> CONFIG_LOG_BUF_SHIFT=14
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> -CONFIG_CGROUP_NS=y
> CONFIG_CGROUP_FREEZER=y
> CONFIG_CGROUP_DEVICE=y
> # CONFIG_CPUSETS is not set
> diff --git a/arch/sh/configs/urquell_defconfig b/arch/sh/configs/urquell_defconfig
> index 28bb19d..e698dff 100644
> --- a/arch/sh/configs/urquell_defconfig
> +++ b/arch/sh/configs/urquell_defconfig
> @@ -82,7 +82,6 @@ CONFIG_IKCONFIG_PROC=y
> CONFIG_LOG_BUF_SHIFT=14
> CONFIG_CGROUPS=y
> CONFIG_CGROUP_DEBUG=y
> -CONFIG_CGROUP_NS=y
> CONFIG_CGROUP_FREEZER=y
> CONFIG_CGROUP_DEVICE=y
> CONFIG_CPUSETS=y
> diff --git a/arch/x86/configs/i386_defconfig b/arch/x86/configs/i386_defconfig
> index d28fad1..4428d5c 100644
> --- a/arch/x86/configs/i386_defconfig
> +++ b/arch/x86/configs/i386_defconfig
> @@ -105,7 +105,6 @@ CONFIG_FAIR_GROUP_SCHED=y
> CONFIG_CGROUP_SCHED=y
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> -CONFIG_CGROUP_NS=y
> CONFIG_CGROUP_FREEZER=y
> # CONFIG_CGROUP_DEVICE is not set
> CONFIG_CPUSETS=y
> diff --git a/arch/x86/configs/x86_64_defconfig b/arch/x86/configs/x86_64_defconfig
> index 6c86acd..2ff947f 100644
> --- a/arch/x86/configs/x86_64_defconfig
> +++ b/arch/x86/configs/x86_64_defconfig
> @@ -105,7 +105,6 @@ CONFIG_FAIR_GROUP_SCHED=y
> CONFIG_CGROUP_SCHED=y
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> -CONFIG_CGROUP_NS=y
> CONFIG_CGROUP_FREEZER=y
> # CONFIG_CGROUP_DEVICE is not set
> CONFIG_CPUSETS=y
> diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
> index f3cbd73..ddbdb77 100644
> --- a/include/linux/cgroup.h
> +++ b/include/linux/cgroup.h
> @@ -552,9 +552,6 @@ static inline struct cgroup* task_cgroup(struct task_struct *task,
> 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;
> diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
> index ccefff0..4ba5259 100644
> --- a/include/linux/cgroup_subsys.h
> +++ b/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
> diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
> index 7b370c7..50d20ab 100644
> --- a/include/linux/nsproxy.h
> +++ b/include/linux/nsproxy.h
> @@ -81,13 +81,4 @@ static inline void get_nsproxy(struct nsproxy *ns)
> atomic_inc(&ns->count);
> }
>
> -#ifdef CONFIG_CGROUP_NS
> -int ns_cgroup_clone(struct task_struct *tsk, struct pid *pid);
> -#else
> -static inline int ns_cgroup_clone(struct task_struct *tsk, struct pid *pid)
> -{
> - return 0;
> -}
> -#endif
> -
> #endif
> diff --git a/init/Kconfig b/init/Kconfig
> index 5cff9a9..1124656 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -496,15 +496,6 @@ 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
> diff --git a/kernel/Makefile b/kernel/Makefile
> index 057472f..a7ee5f4 100644
> --- a/kernel/Makefile
> +++ b/kernel/Makefile
> @@ -62,7 +62,6 @@ 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
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 09fb6f9..7ec5bad 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -4212,122 +4212,6 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks)
> }
>
> /**
> - * 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
> diff --git a/kernel/cpuset.c b/kernel/cpuset.c
> index 02b9611..4613840 100644
> --- a/kernel/cpuset.c
> +++ b/kernel/cpuset.c
> @@ -1829,10 +1829,9 @@ static int cpuset_populate(struct cgroup_subsys *ss, struct cgroup *cont)
> }
>
> /*
> - * post_clone() is called at the end of cgroup_clone().
> - * 'cgroup' was just created automatically as a result of
> - * a cgroup_clone(), and the current task is about to
> - * be moved into 'cgroup'.
> + * post_clone() is called during cgroup_create() when the
> + * clone_children mount argument was specified. The cgroup
> + * can not yet have any tasks.
> *
> * Currently we refuse to set up the cgroup - thereby
> * refusing the task to be entered, and as a result refusing
> diff --git a/kernel/fork.c b/kernel/fork.c
> index b6cce14..c391b1d 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -1167,12 +1167,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
> 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()?
> diff --git a/kernel/ns_cgroup.c b/kernel/ns_cgroup.c
> deleted file mode 100644
> index 2a5dfec..0000000
> --- a/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,
> -};
> diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
> index f74e6c0..014a90d 100644
> --- a/kernel/nsproxy.c
> +++ b/kernel/nsproxy.c
> @@ -198,10 +198,6 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
> goto out;
> }
>
> - err = ns_cgroup_clone(current, task_pid(current));
> - if (err)
> - put_nsproxy(*new_nsp);
> -
> out:
> return err;
> }
> --
> 1.7.0.4
>
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