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sched/headers, cgroups: Remove the threadgroup_change_*() wrappery

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threadgroup_change_begin()/end() is a pointless wrapper around
cgroup_threadgroup_change_begin()/end(), minus a might_sleep()
in the !CONFIG_CGROUPS=y case.

Remove the wrappery, move the might_sleep() (the down_read()
already has a might_sleep() check).

This debloats <linux/sched.h> a bit and simplifies this API.

Update all call sites.

No change in functionality.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2017-02-02 11:50:56 +01:00
parent f9411ebe3d
commit 780de9dd27
6 changed files with 18 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
fs/exec.c
View File

@ -1088,7 +1088,7 @@ static int de_thread(struct task_struct *tsk)
struct task_struct *leader = tsk->group_leader;
for (;;) {
threadgroup_change_begin(tsk);
cgroup_threadgroup_change_begin(tsk);
write_lock_irq(&tasklist_lock);
/*
* Do this under tasklist_lock to ensure that
@ -1099,7 +1099,7 @@ static int de_thread(struct task_struct *tsk)
break;
__set_current_state(TASK_KILLABLE);
write_unlock_irq(&tasklist_lock);
threadgroup_change_end(tsk);
cgroup_threadgroup_change_end(tsk);
schedule();
if (unlikely(__fatal_signal_pending(tsk)))
goto killed;
@ -1157,7 +1157,7 @@ static int de_thread(struct task_struct *tsk)
if (unlikely(leader->ptrace))
__wake_up_parent(leader, leader->parent);
write_unlock_irq(&tasklist_lock);
threadgroup_change_end(tsk);
cgroup_threadgroup_change_end(tsk);
release_task(leader);
}

13
include/linux/cgroup-defs.h
View File

@ -531,8 +531,8 @@ extern struct percpu_rw_semaphore cgroup_threadgroup_rwsem;
* cgroup_threadgroup_change_begin - threadgroup exclusion for cgroups
* @tsk: target task
*
* Called from threadgroup_change_begin() and allows cgroup operations to
* synchronize against threadgroup changes using a percpu_rw_semaphore.
* Allows cgroup operations to synchronize against threadgroup changes
* using a percpu_rw_semaphore.
*/
static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk)
{
@ -543,8 +543,7 @@ static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk)
* cgroup_threadgroup_change_end - threadgroup exclusion for cgroups
* @tsk: target task
*
* Called from threadgroup_change_end(). Counterpart of
* cgroup_threadcgroup_change_begin().
* Counterpart of cgroup_threadcgroup_change_begin().
*/
static inline void cgroup_threadgroup_change_end(struct task_struct *tsk)
{
@ -555,7 +554,11 @@ static inline void cgroup_threadgroup_change_end(struct task_struct *tsk)
#define CGROUP_SUBSYS_COUNT 0
static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) {}
static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk)
{
might_sleep();
}
static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) {}
#endif /* CONFIG_CGROUPS */

28
include/linux/sched.h
View File

@ -3162,34 +3162,6 @@ static inline void unlock_task_sighand(struct task_struct *tsk,
spin_unlock_irqrestore(&tsk->sighand->siglock, *flags);
}
/**
* threadgroup_change_begin - mark the beginning of changes to a threadgroup
* @tsk: task causing the changes
*
* All operations which modify a threadgroup - a new thread joining the
* group, death of a member thread (the assertion of PF_EXITING) and
* exec(2) dethreading the process and replacing the leader - are wrapped
* by threadgroup_change_{begin|end}(). This is to provide a place which
* subsystems needing threadgroup stability can hook into for
* synchronization.
*/
static inline void threadgroup_change_begin(struct task_struct *tsk)
{
might_sleep();
cgroup_threadgroup_change_begin(tsk);
}
/**
* threadgroup_change_end - mark the end of changes to a threadgroup
* @tsk: task causing the changes
*
* See threadgroup_change_begin().
*/
static inline void threadgroup_change_end(struct task_struct *tsk)
{
cgroup_threadgroup_change_end(tsk);
}
#ifdef CONFIG_THREAD_INFO_IN_TASK
static inline struct thread_info *task_thread_info(struct task_struct *task)

2
kernel/cgroup/pids.c
View File

@ -214,7 +214,7 @@ static void pids_cancel_attach(struct cgroup_taskset *tset)
/*
* task_css_check(true) in pids_can_fork() and pids_cancel_fork() relies
* on threadgroup_change_begin() held by the copy_process().
* on cgroup_threadgroup_change_begin() held by the copy_process().
*/
static int pids_can_fork(struct task_struct *task)
{

6
kernel/fork.c
View File

@ -1746,7 +1746,7 @@ static __latent_entropy struct task_struct *copy_process(
INIT_LIST_HEAD(&p->thread_group);
p->task_works = NULL;
threadgroup_change_begin(current);
cgroup_threadgroup_change_begin(current);
/*
* Ensure that the cgroup subsystem policies allow the new process to be
* forked. It should be noted the the new process's css_set can be changed
@ -1843,7 +1843,7 @@ static __latent_entropy struct task_struct *copy_process(
proc_fork_connector(p);
cgroup_post_fork(p);
threadgroup_change_end(current);
cgroup_threadgroup_change_end(current);
perf_event_fork(p);
trace_task_newtask(p, clone_flags);
@ -1854,7 +1854,7 @@ static __latent_entropy struct task_struct *copy_process(
bad_fork_cancel_cgroup:
cgroup_cancel_fork(p);
bad_fork_free_pid:
threadgroup_change_end(current);
cgroup_threadgroup_change_end(current);
if (pid != &init_struct_pid)
free_pid(pid);
bad_fork_cleanup_thread:

6
kernel/signal.c
View File

@ -2395,11 +2395,11 @@ void exit_signals(struct task_struct *tsk)
* @tsk is about to have PF_EXITING set - lock out users which
* expect stable threadgroup.
*/
threadgroup_change_begin(tsk);
cgroup_threadgroup_change_begin(tsk);
if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
tsk->flags |= PF_EXITING;
threadgroup_change_end(tsk);
cgroup_threadgroup_change_end(tsk);
return;
}
@ -2410,7 +2410,7 @@ void exit_signals(struct task_struct *tsk)
*/
tsk->flags |= PF_EXITING;
threadgroup_change_end(tsk);
cgroup_threadgroup_change_end(tsk);
if (!signal_pending(tsk))
goto out;