From: Oleg Nesterov <oleg@tv-sign.ru>
Date: Fri, 29 Sep 2006 09:01:10 +0000 (-0700)
Subject: [PATCH] kill PF_DEAD flag
X-Git-Tag: v2.6.19-rc1~700
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=55a101f8f71a3d3dbda7b5c77083ffe47552f831;p=linux-2.6

[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: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/include/linux/sched.h b/include/linux/sched.h
index fbc69cc392..9763de334f 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -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 */
diff --git a/kernel/exit.c b/kernel/exit.c
index 3d759c98fb..9dd5f1336d 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -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();
@@ -972,7 +970,7 @@ NORET_TYPE void complete_and_exit(struct completion *comp, long code)
 {
 	if (comp)
 		complete(comp);
-	
+
 	do_exit(code);
 }
 
diff --git a/kernel/sched.c b/kernel/sched.c
index e1646b044b..a9405d7cc6 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -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);
 
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index f3dd79c1c3..202f186a75 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -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;