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Merge branch 'for-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

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* 'for-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (21 commits)
  cgroup: fix to allow mounting a hierarchy by name
  cgroup: move assignement out of condition in cgroup_attach_proc()
  cgroup: Remove task_lock() from cgroup_post_fork()
  cgroup: add sparse annotation to cgroup_iter_start() and cgroup_iter_end()
  cgroup: mark cgroup_rmdir_waitq and cgroup_attach_proc() as static
  cgroup: only need to check oldcgrp==newgrp once
  cgroup: remove redundant get/put of task struct
  cgroup: remove redundant get/put of old css_set from migrate
  cgroup: Remove unnecessary task_lock before fetching css_set on migration
  cgroup: Drop task_lock(parent) on cgroup_fork()
  cgroups: remove redundant get/put of css_set from css_set_check_fetched()
  resource cgroups: remove bogus cast
  cgroup: kill subsys->can_attach_task(), pre_attach() and attach_task()
  cgroup, cpuset: don't use ss->pre_attach()
  cgroup: don't use subsys->can_attach_task() or ->attach_task()
  cgroup: introduce cgroup_taskset and use it in subsys->can_attach(), cancel_attach() and attach()
  cgroup: improve old cgroup handling in cgroup_attach_proc()
  cgroup: always lock threadgroup during migration
  threadgroup: extend threadgroup_lock() to cover exit and exec
  threadgroup: rename signal->threadgroup_fork_lock to ->group_rwsem
  ...

Fix up conflict in kernel/cgroup.c due to commit e0197aae59: "cgroups:
fix a css_set not found bug in cgroup_attach_proc" that already
mentioned that the bug is fixed (differently) in Tejun's cgroup
patchset. This one, in other words.
This commit is contained in:
Linus Torvalds
2012-01-09 12:59:24 -08:00
parent ac69e09280 0d19ea8665
commit db0c2bf69a
15 changed files with 471 additions and 350 deletions
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73
include/linux/sched.h
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@@ -637,13 +637,15 @@ struct signal_struct {
#endif
#ifdef CONFIG_CGROUPS
/*
* The threadgroup_fork_lock prevents threads from forking with
* CLONE_THREAD while held for writing. Use this for fork-sensitive
* threadgroup-wide operations. It's taken for reading in fork.c in
* copy_process().
* Currently only needed write-side by cgroups.
* group_rwsem prevents new tasks from entering the threadgroup and
* member tasks from exiting,a more specifically, setting of
* PF_EXITING. fork and exit paths are protected with this rwsem
* using threadgroup_change_begin/end(). Users which require
* threadgroup to remain stable should use threadgroup_[un]lock()
* which also takes care of exec path. Currently, cgroup is the
* only user.
*/
struct rw_semaphore threadgroup_fork_lock;
struct rw_semaphore group_rwsem;
#endif
int oom_adj; /* OOM kill score adjustment (bit shift) */
@@ -2394,29 +2396,62 @@ static inline void unlock_task_sighand(struct task_struct *tsk,
spin_unlock_irqrestore(&tsk->sighand->siglock, *flags);
}
/* See the declaration of threadgroup_fork_lock in signal_struct. */
#ifdef CONFIG_CGROUPS
static inline void threadgroup_fork_read_lock(struct task_struct *tsk)
static inline void threadgroup_change_begin(struct task_struct *tsk)
{
down_read(&tsk->signal->threadgroup_fork_lock);
down_read(&tsk->signal->group_rwsem);
}
static inline void threadgroup_fork_read_unlock(struct task_struct *tsk)
static inline void threadgroup_change_end(struct task_struct *tsk)
{
up_read(&tsk->signal->threadgroup_fork_lock);
up_read(&tsk->signal->group_rwsem);
}
static inline void threadgroup_fork_write_lock(struct task_struct *tsk)
/**
* threadgroup_lock - lock threadgroup
* @tsk: member task of the threadgroup to lock
*
* Lock the threadgroup @tsk belongs to. No new task is allowed to enter
* and member tasks aren't allowed to exit (as indicated by PF_EXITING) or
* perform exec. This is useful for cases where the threadgroup needs to
* stay stable across blockable operations.
*
* fork and exit paths explicitly call threadgroup_change_{begin|end}() for
* synchronization. While held, no new task will be added to threadgroup
* and no existing live task will have its PF_EXITING set.
*
* During exec, a task goes and puts its thread group through unusual
* changes. After de-threading, exclusive access is assumed to resources
* which are usually shared by tasks in the same group - e.g. sighand may
* be replaced with a new one. Also, the exec'ing task takes over group
* leader role including its pid. Exclude these changes while locked by
* grabbing cred_guard_mutex which is used to synchronize exec path.
*/
static inline void threadgroup_lock(struct task_struct *tsk)
{
down_write(&tsk->signal->threadgroup_fork_lock);
/*
* exec uses exit for de-threading nesting group_rwsem inside
* cred_guard_mutex. Grab cred_guard_mutex first.
*/
mutex_lock(&tsk->signal->cred_guard_mutex);
down_write(&tsk->signal->group_rwsem);
}
static inline void threadgroup_fork_write_unlock(struct task_struct *tsk)
/**
* threadgroup_unlock - unlock threadgroup
* @tsk: member task of the threadgroup to unlock
*
* Reverse threadgroup_lock().
*/
static inline void threadgroup_unlock(struct task_struct *tsk)
{
up_write(&tsk->signal->threadgroup_fork_lock);
up_write(&tsk->signal->group_rwsem);
mutex_unlock(&tsk->signal->cred_guard_mutex);
}
#else
static inline void threadgroup_fork_read_lock(struct task_struct *tsk) {}
static inline void threadgroup_fork_read_unlock(struct task_struct *tsk) {}
static inline void threadgroup_fork_write_lock(struct task_struct *tsk) {}
static inline void threadgroup_fork_write_unlock(struct task_struct *tsk) {}
static inline void threadgroup_change_begin(struct task_struct *tsk) {}
static inline void threadgroup_change_end(struct task_struct *tsk) {}
static inline void threadgroup_lock(struct task_struct *tsk) {}
static inline void threadgroup_unlock(struct task_struct *tsk) {}
#endif
#ifndef __HAVE_THREAD_FUNCTIONS