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Commit 55a101f8 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

[PATCH] kill PF_DEAD flag 



After the previous change (->flags & PF_DEAD) <=> (->state == EXIT_DEAD), we
don't need PF_DEAD any longer.

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 29b88492

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;