Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (000b8949) · Commits · 戴 / test

include/linux/sched.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -2567,6 +2567,7 @@ extern void sched_autogroup_create_attach(struct task_struct *p);
		extern void sched_autogroup_detach(struct task_struct *p);
		extern void sched_autogroup_fork(struct signal_struct *sig);
		extern void sched_autogroup_exit(struct signal_struct *sig);
		extern void sched_autogroup_exit_task(struct task_struct *p);
		#ifdef CONFIG_PROC_FS
		extern void proc_sched_autogroup_show_task(struct task_struct p, struct seq_file m);
		extern int proc_sched_autogroup_set_nice(struct task_struct *p, int nice);
		@@ -2576,6 +2577,7 @@ static inline void sched_autogroup_create_attach(struct task_struct *p) { }
		static inline void sched_autogroup_detach(struct task_struct *p) { }
		static inline void sched_autogroup_fork(struct signal_struct *sig) { }
		static inline void sched_autogroup_exit(struct signal_struct *sig) { }
		static inline void sched_autogroup_exit_task(struct task_struct *p) { }
		#endif

		extern int yield_to(struct task_struct *p, bool preempt);

kernel/exit.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -836,6 +836,7 @@ void __noreturn do_exit(long code)
		*/
		perf_event_exit_task(tsk);

		sched_autogroup_exit_task(tsk);
		cgroup_exit(tsk);

		/*

kernel/sched/auto_group.c

+28 −8

Original line number	Diff line number	Diff line
		@@ -111,10 +111,13 @@ bool task_wants_autogroup(struct task_struct p, struct task_group tg)
		{
		if (tg != &root_task_group)
		return false;

		/*
		* We can only assume the task group can't go away on us if
		* autogroup_move_group() can see us on ->thread_group list.
		* If we race with autogroup_move_group() the caller can use the old
		* value of signal->autogroup but in this case sched_move_task() will
		* be called again before autogroup_kref_put().
		*
		* However, there is no way sched_autogroup_exit_task() could tell us
		* to avoid autogroup->tg, so we abuse PF_EXITING flag for this case.
		*/
		if (p->flags & PF_EXITING)
		return false;
		@@ -122,6 +125,16 @@ bool task_wants_autogroup(struct task_struct p, struct task_group tg)
		return true;
		}

		void sched_autogroup_exit_task(struct task_struct *p)
		{
		/*
		* We are going to call exit_notify() and autogroup_move_group() can't
		* see this thread after that: we can no longer use signal->autogroup.
		* See the PF_EXITING check in task_wants_autogroup().
		*/
		sched_move_task(p);
		}

		static void
		autogroup_move_group(struct task_struct p, struct autogroup ag)
		{
		@@ -138,13 +151,20 @@ autogroup_move_group(struct task_struct p, struct autogroup ag)
		}

		p->signal->autogroup = autogroup_kref_get(ag);

		if (!READ_ONCE(sysctl_sched_autogroup_enabled))
		goto out;

		/*
		* We can't avoid sched_move_task() after we changed signal->autogroup,
		* this process can already run with task_group() == prev->tg or we can
		* race with cgroup code which can read autogroup = prev under rq->lock.
		* In the latter case for_each_thread() can not miss a migrating thread,
		* cpu_cgroup_attach() must not be possible after cgroup_exit() and it
		* can't be removed from thread list, we hold ->siglock.
		*
		* If an exiting thread was already removed from thread list we rely on
		* sched_autogroup_exit_task().
		*/
		for_each_thread(p, t)
		sched_move_task(t);
		out:

		unlock_task_sighand(p, &flags);
		autogroup_kref_put(prev);
		}

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