Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
sched/headers, cgroups: Remove the threadgroup_change_*() wrappery
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>
+18
-43
+3
-3
fs/exec.c
+3
-3
fs/exec.c
···
1088
1088
struct task_struct *leader = tsk->group_leader;
1089
1089
1090
1090
for (;;) {
1091
-
threadgroup_change_begin(tsk);
1091
+
cgroup_threadgroup_change_begin(tsk);
1092
1092
write_lock_irq(&tasklist_lock);
1093
1093
/*
1094
1094
* Do this under tasklist_lock to ensure that
···
1099
1099
break;
1100
1100
__set_current_state(TASK_KILLABLE);
1101
1101
write_unlock_irq(&tasklist_lock);
1102
-
threadgroup_change_end(tsk);
1102
+
cgroup_threadgroup_change_end(tsk);
1103
1103
schedule();
1104
1104
if (unlikely(__fatal_signal_pending(tsk)))
1105
1105
goto killed;
···
1157
1157
if (unlikely(leader->ptrace))
1158
1158
__wake_up_parent(leader, leader->parent);
1159
1159
write_unlock_irq(&tasklist_lock);
1160
-
threadgroup_change_end(tsk);
1160
+
cgroup_threadgroup_change_end(tsk);
1161
1161
1162
1162
release_task(leader);
1163
1163
}
+8
-5
include/linux/cgroup-defs.h
+8
-5
include/linux/cgroup-defs.h
···
531
531
* cgroup_threadgroup_change_begin - threadgroup exclusion for cgroups
532
532
* @tsk: target task
533
533
*
534
-
* Called from threadgroup_change_begin() and allows cgroup operations to
535
-
* synchronize against threadgroup changes using a percpu_rw_semaphore.
534
+
* Allows cgroup operations to synchronize against threadgroup changes
535
+
* using a percpu_rw_semaphore.
536
536
*/
537
537
static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk)
538
538
{
···
543
543
* cgroup_threadgroup_change_end - threadgroup exclusion for cgroups
544
544
* @tsk: target task
545
545
*
546
-
* Called from threadgroup_change_end(). Counterpart of
547
-
* cgroup_threadcgroup_change_begin().
546
+
* Counterpart of cgroup_threadcgroup_change_begin().
548
547
*/
549
548
static inline void cgroup_threadgroup_change_end(struct task_struct *tsk)
550
549
{
···
554
555
555
556
#define CGROUP_SUBSYS_COUNT 0
556
557
557
-
static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk) {}
558
+
static inline void cgroup_threadgroup_change_begin(struct task_struct *tsk)
559
+
{
560
+
might_sleep();
561
+
}
562
+
558
563
static inline void cgroup_threadgroup_change_end(struct task_struct *tsk) {}
559
564
560
565
#endif /* CONFIG_CGROUPS */
-28
include/linux/sched.h
-28
include/linux/sched.h
···
3162
3162
spin_unlock_irqrestore(&tsk->sighand->siglock, *flags);
3163
3163
}
3164
3164
3165
-
/**
3166
-
* threadgroup_change_begin - mark the beginning of changes to a threadgroup
3167
-
* @tsk: task causing the changes
3168
-
*
3169
-
* All operations which modify a threadgroup - a new thread joining the
3170
-
* group, death of a member thread (the assertion of PF_EXITING) and
3171
-
* exec(2) dethreading the process and replacing the leader - are wrapped
3172
-
* by threadgroup_change_{begin|end}(). This is to provide a place which
3173
-
* subsystems needing threadgroup stability can hook into for
3174
-
* synchronization.
3175
-
*/
3176
-
static inline void threadgroup_change_begin(struct task_struct *tsk)
3177
-
{
3178
-
might_sleep();
3179
-
cgroup_threadgroup_change_begin(tsk);
3180
-
}
3181
-
3182
-
/**
3183
-
* threadgroup_change_end - mark the end of changes to a threadgroup
3184
-
* @tsk: task causing the changes
3185
-
*
3186
-
* See threadgroup_change_begin().
3187
-
*/
3188
-
static inline void threadgroup_change_end(struct task_struct *tsk)
3189
-
{
3190
-
cgroup_threadgroup_change_end(tsk);
3191
-
}
3192
-
3193
3165
#ifdef CONFIG_THREAD_INFO_IN_TASK
3194
3166
3195
3167
static inline struct thread_info *task_thread_info(struct task_struct *task)
+1
-1
kernel/cgroup/pids.c
+1
-1
kernel/cgroup/pids.c
···
214
214
215
215
/*
216
216
* task_css_check(true) in pids_can_fork() and pids_cancel_fork() relies
217
-
* on threadgroup_change_begin() held by the copy_process().
217
+
* on cgroup_threadgroup_change_begin() held by the copy_process().
218
218
*/
219
219
static int pids_can_fork(struct task_struct *task)
220
220
{
+3
-3
kernel/fork.c
+3
-3
kernel/fork.c
···
1746
1746
INIT_LIST_HEAD(&p->thread_group);
1747
1747
p->task_works = NULL;
1748
1748
1749
-
threadgroup_change_begin(current);
1749
+
cgroup_threadgroup_change_begin(current);
1750
1750
/*
1751
1751
* Ensure that the cgroup subsystem policies allow the new process to be
1752
1752
* forked. It should be noted the the new process's css_set can be changed
···
1843
1843
1844
1844
proc_fork_connector(p);
1845
1845
cgroup_post_fork(p);
1846
-
threadgroup_change_end(current);
1846
+
cgroup_threadgroup_change_end(current);
1847
1847
perf_event_fork(p);
1848
1848
1849
1849
trace_task_newtask(p, clone_flags);
···
1854
1854
bad_fork_cancel_cgroup:
1855
1855
cgroup_cancel_fork(p);
1856
1856
bad_fork_free_pid:
1857
-
threadgroup_change_end(current);
1857
+
cgroup_threadgroup_change_end(current);
1858
1858
if (pid != &init_struct_pid)
1859
1859
free_pid(pid);
1860
1860
bad_fork_cleanup_thread:
+3
-3
kernel/signal.c
+3
-3
kernel/signal.c
···
2395
2395
* @tsk is about to have PF_EXITING set - lock out users which
2396
2396
* expect stable threadgroup.
2397
2397
*/
2398
-
threadgroup_change_begin(tsk);
2398
+
cgroup_threadgroup_change_begin(tsk);
2399
2399
2400
2400
if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
2401
2401
tsk->flags |= PF_EXITING;
2402
-
threadgroup_change_end(tsk);
2402
+
cgroup_threadgroup_change_end(tsk);
2403
2403
return;
2404
2404
}
2405
2405
···
2410
2410
*/
2411
2411
tsk->flags |= PF_EXITING;
2412
2412
2413
-
threadgroup_change_end(tsk);
2413
+
cgroup_threadgroup_change_end(tsk);
2414
2414
2415
2415
if (!signal_pending(tsk))
2416
2416
goto out;