v2 PF_DEAD: kill it

PATCH New Oleg Nesterov 1 participant 1 message Nov 25, 2005

Subsystems (3)

Memory management Scheduler Memory management - OOM killer

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Oleg Nesterov

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2005-11-25 15:04 UTC #0 lore raw

PATCH 1/2 v2 PF_DEAD: kill it

PF_DEAD has nothing to do with process state, it is just indication that task_struct should be freed after the last schedule.

After the previous change (->flags & PF_DEAD) <=> (->state == STATE_DEAD), so we can forget about PF_DEAD flag.

Signed-off-by Oleg Nesterov <[email protected]>

include/linux/sched.h renamed from include/linux/sched.h~2_KILL +0 -1

@@ -891,7 +891,6 @@ do { if (atomic_dec_and_test(&(tsk)->usa
 					/* 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 renamed from kernel/exit.c~2_KILL +1 -3

@@ -871,10 +871,8 @@ fastcall NORET_TYPE void do_exit(long co
 	tsk->mempolicy = NULL;
 #endif
 
-	/* PF_DEAD causes final put_task_struct after we schedule. */
+	/* ->state == TASK_DEAD causes final put_task_struct after we schedule. */
 	preempt_disable();
-	BUG_ON(tsk->flags & PF_DEAD);
-	tsk->flags |= PF_DEAD;
 	tsk->state = TASK_DEAD;
 
 	schedule();

kernel/sched.c renamed from kernel/sched.c~2_KILL +4 -4

@@ -1615,7 +1615,7 @@ static inline void finish_task_switch(ru
 	__releases(rq->lock)
 {
 	struct mm_struct *mm = rq->prev_mm;
-	unsigned long prev_task_flags;
+	int task_dead;
 
 	rq->prev_mm = NULL;

@@ -1630,12 +1630,12 @@ static inline void finish_task_switch(ru
 	 * be dropped twice.
 	 *		Manfred Spraul <[email protected]>
 	 */
-	prev_task_flags = prev->flags;
+	task_dead = (prev->state == TASK_DEAD);
 	finish_arch_switch(prev);
 	finish_lock_switch(rq, prev);
 	if (mm)
 		mmdrop(mm);
-	if (unlikely(prev_task_flags & PF_DEAD))
+	if (unlikely(task_dead))
 		put_task_struct(prev);
 }

@@ -4711,7 +4711,7 @@ static void migrate_dead(unsigned int de
 	BUG_ON(tsk->exit_state != EXIT_ZOMBIE && tsk->exit_state != EXIT_DEAD);
 
 	/* Cannot have done final schedule yet: would have vanished. */
-	BUG_ON(tsk->flags & PF_DEAD);
+	BUG_ON(tsk->state == TASK_DEAD);
 
 	get_task_struct(tsk);

mm/oom_kill.c renamed from mm/oom_kill.c~2_KILL +1 -1

@@ -163,7 +163,7 @@ static struct task_struct * select_bad_p
 		 */
 		releasing = test_tsk_thread_flag(p, TIF_MEMDIE) ||
 						p->flags & PF_EXITING;
-		if (releasing && !(p->flags & PF_DEAD))
+		if (releasing && (p->state != TASK_DEAD))
 			return ERR_PTR(-1UL);
 		if (p->flags & PF_SWAPOFF)
 			return p;