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

From: Oleg Nesterov
Date: Thu Jun 10 2010 - 19:11:42 EST


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@xxxxxxxxxx>
---

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;

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