[PATCH] kill PF_DEAD flag (55a101f8) · Commits · 戴 / test

include/linux/sched.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -1061,7 +1061,6 @@ static inline void put_task_struct(struct task_struct *t)
		/* Not implemented yet, only for 486*/
		#define PF_STARTING 0x00000002 /* being created */
		#define PF_EXITING 0x00000004 /* getting shut down */
		#define PF_DEAD 0x00000008 /* Dead */
		#define PF_FORKNOEXEC 0x00000040 /* forked but didn't exec */
		#define PF_SUPERPRIV 0x00000100 /* used super-user privileges */
		#define PF_DUMPCORE 0x00000200 /* dumped core */

kernel/exit.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -953,10 +953,8 @@ fastcall NORET_TYPE void do_exit(long code)
		if (tsk->splice_pipe)
		__free_pipe_info(tsk->splice_pipe);

		/* PF_DEAD causes final put_task_struct after we schedule. */
		preempt_disable();
		BUG_ON(tsk->flags & PF_DEAD);
		tsk->flags \|= PF_DEAD;
		/* causes final put_task_struct in finish_task_switch(). */
		tsk->state = EXIT_DEAD;

		schedule();

kernel/sched.c

+8 −8

Original line number	Diff line number	Diff line
		@@ -1755,27 +1755,27 @@ static inline void finish_task_switch(struct rq rq, struct task_struct prev)
		__releases(rq->lock)
		{
		struct mm_struct *mm = rq->prev_mm;
		unsigned long prev_task_flags;
		long prev_state;

		rq->prev_mm = NULL;

		/*
		* A task struct has one reference for the use as "current".
		* If a task dies, then it sets EXIT_ZOMBIE in tsk->exit_state and
		* calls schedule one last time. The schedule call will never return,
		* and the scheduled task must drop that reference.
		* The test for EXIT_ZOMBIE must occur while the runqueue locks are
		* If a task dies, then it sets EXIT_DEAD in tsk->state and calls
		* schedule one last time. The schedule call will never return, and
		* the scheduled task must drop that reference.
		* The test for EXIT_DEAD must occur while the runqueue locks are
		* still held, otherwise prev could be scheduled on another cpu, die
		* there before we look at prev->state, and then the reference would
		* be dropped twice.
		* Manfred Spraul <manfred@colorfullife.com>
		*/
		prev_task_flags = prev->flags;
		prev_state = prev->state;
		finish_arch_switch(prev);
		finish_lock_switch(rq, prev);
		if (mm)
		mmdrop(mm);
		if (unlikely(prev_task_flags & PF_DEAD)) {
		if (unlikely(prev_state == EXIT_DEAD)) {
		/*
		* Remove function-return probe instances associated with this
		* task and put them back on the free list.
		@@ -5153,7 +5153,7 @@ static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
		BUG_ON(p->exit_state != EXIT_ZOMBIE && p->exit_state != EXIT_DEAD);

		/* Cannot have done final schedule yet: would have vanished. */
		BUG_ON(p->flags & PF_DEAD);
		BUG_ON(p->state == EXIT_DEAD);

		get_task_struct(p);

mm/oom_kill.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -226,8 +226,8 @@ static struct task_struct select_bad_process(unsigned long ppoints)
		releasing = test_tsk_thread_flag(p, TIF_MEMDIE) \|\|
		p->flags & PF_EXITING;
		if (releasing) {
		/* PF_DEAD tasks have already released their mm */
		if (p->flags & PF_DEAD)
		/* TASK_DEAD tasks have already released their mm */
		if (p->state == EXIT_DEAD)
		continue;
		if (p->flags & PF_EXITING && p == current) {
		chosen = p;

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