[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 fbc69cc..9763de3 100644 (file)
--- 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 3d759c9..9dd5f13 100644 (file)
--- 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 e1646b0..a9405d7 100644 (file)
--- 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 f3dd79c..202f186 100644 (file)
--- 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;