[PATCH 3/5] sched_stats: remove the obsolete exit_state/signal hacks

[PATCH 3/5] sched_stats: remove the obsolete exit_state/signal hacks

[Oleg Nesterov]

account_group_xxx() functions check ->exit_state to ensure that
current->signal is valid and can't go away. This is not needed
since ea6d290c, task->signal is pinned to task_struct.

The comment and another hack in account_group_exec_runtime() refers
to task_rq_unlock_wait() which was already removed by b7b8ff63.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---

 kernel/sched_stats.h |   27 +++------------------------
 1 file changed, 3 insertions(+), 24 deletions(-)

--- 35-rc2/kernel/sched_stats.h~3_STATS_DONT_CK_EXIT_CODE	2010-06-11 00:47:33.000000000 +0200
+++ 35-rc2/kernel/sched_stats.h	2010-06-11 01:07:37.000000000 +0200
@@ -295,13 +295,7 @@ sched_info_switch(struct task_struct *pr
 static inline void account_group_user_time(struct task_struct *tsk,
 					   cputime_t cputime)
 {
-	struct thread_group_cputimer *cputimer;
-
-	/* tsk == current, ensure it is safe to use ->signal */
-	if (unlikely(tsk->exit_state))
-		return;
-
-	cputimer = &tsk->signal->cputimer;
+	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 
 	if (!cputimer->running)
 		return;
@@ -325,13 +319,7 @@ static inline void account_group_user_ti
 static inline void account_group_system_time(struct task_struct *tsk,
 					     cputime_t cputime)
 {
-	struct thread_group_cputimer *cputimer;
-
-	/* tsk == current, ensure it is safe to use ->signal */
-	if (unlikely(tsk->exit_state))
-		return;
-
-	cputimer = &tsk->signal->cputimer;
+	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 
 	if (!cputimer->running)
 		return;
@@ -355,16 +343,7 @@ static inline void account_group_system_
 static inline void account_group_exec_runtime(struct task_struct *tsk,
 					      unsigned long long ns)
 {
-	struct thread_group_cputimer *cputimer;
-	struct signal_struct *sig;
-
-	sig = tsk->signal;
-	/* see __exit_signal()->task_rq_unlock_wait() */
-	barrier();
-	if (unlikely(!sig))
-		return;
-
-	cputimer = &sig->cputimer;
+	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 
 	if (!cputimer->running)
 		return;

[tip:sched/core] sched: Remove the obsolete exit_state/signal hacks

[tip-bot for Oleg Nesterov]

Commit-ID:  48286d5088a3ba76de40a6b70221632a49cab7a1
Gitweb:     http://git.kernel.org/tip/48286d5088a3ba76de40a6b70221632a49cab7a1
Author:     Oleg Nesterov <oleg@redhat.com>
AuthorDate: Fri, 11 Jun 2010 01:09:52 +0200
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 18 Jun 2010 10:46:56 +0200

sched: Remove the obsolete exit_state/signal hacks

account_group_xxx() functions check ->exit_state to ensure that
current->signal is valid and can't go away. This is not needed
since ea6d290c, task->signal is pinned to task_struct.

The comment and another hack in account_group_exec_runtime() refers
to task_rq_unlock_wait() which was already removed by b7b8ff63.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100610230952.GA25914@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/sched_stats.h |   27 +++------------------------
 1 files changed, 3 insertions(+), 24 deletions(-)

diff --git a/kernel/sched_stats.h b/kernel/sched_stats.h
index 32d2bd4..25c2f96 100644
--- a/kernel/sched_stats.h
+++ b/kernel/sched_stats.h
@@ -295,13 +295,7 @@ sched_info_switch(struct task_struct *prev, struct task_struct *next)
 static inline void account_group_user_time(struct task_struct *tsk,
 					   cputime_t cputime)
 {
-	struct thread_group_cputimer *cputimer;
-
-	/* tsk == current, ensure it is safe to use ->signal */
-	if (unlikely(tsk->exit_state))
-		return;
-
-	cputimer = &tsk->signal->cputimer;
+	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 
 	if (!cputimer->running)
 		return;
@@ -325,13 +319,7 @@ static inline void account_group_user_time(struct task_struct *tsk,
 static inline void account_group_system_time(struct task_struct *tsk,
 					     cputime_t cputime)
 {
-	struct thread_group_cputimer *cputimer;
-
-	/* tsk == current, ensure it is safe to use ->signal */
-	if (unlikely(tsk->exit_state))
-		return;
-
-	cputimer = &tsk->signal->cputimer;
+	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 
 	if (!cputimer->running)
 		return;
@@ -355,16 +343,7 @@ static inline void account_group_system_time(struct task_struct *tsk,
 static inline void account_group_exec_runtime(struct task_struct *tsk,
 					      unsigned long long ns)
 {
-	struct thread_group_cputimer *cputimer;
-	struct signal_struct *sig;
-
-	sig = tsk->signal;
-	/* see __exit_signal()->task_rq_unlock_wait() */
-	barrier();
-	if (unlikely(!sig))
-		return;
-
-	cputimer = &sig->cputimer;
+	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
 
 	if (!cputimer->running)
 		return;