timers: Omit POSIX timer stuff from task_struct when disabled
When CONFIG_POSIX_TIMERS is disabled, it is preferable to remove related
structures from struct task_struct and struct signal_struct as they
won't contain anything useful and shouldn't be relied upon by mistake.
Code still referencing those structures is also disabled here.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/kernel/fork.c b/kernel/fork.c
index 11c5c8a..105c667 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1304,6 +1304,7 @@ void __cleanup_sighand(struct sighand_struct *sighand)
}
}
+#ifdef CONFIG_POSIX_TIMERS
/*
* Initialize POSIX timer handling for a thread group.
*/
@@ -1322,6 +1323,9 @@ static void posix_cpu_timers_init_group(struct signal_struct *sig)
INIT_LIST_HEAD(&sig->cpu_timers[1]);
INIT_LIST_HEAD(&sig->cpu_timers[2]);
}
+#else
+static inline void posix_cpu_timers_init_group(struct signal_struct *sig) { }
+#endif
static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
{
@@ -1346,11 +1350,11 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
init_waitqueue_head(&sig->wait_chldexit);
sig->curr_target = tsk;
init_sigpending(&sig->shared_pending);
- INIT_LIST_HEAD(&sig->posix_timers);
seqlock_init(&sig->stats_lock);
prev_cputime_init(&sig->prev_cputime);
#ifdef CONFIG_POSIX_TIMERS
+ INIT_LIST_HEAD(&sig->posix_timers);
hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
sig->real_timer.function = it_real_fn;
#endif
@@ -1425,6 +1429,7 @@ static void rt_mutex_init_task(struct task_struct *p)
#endif
}
+#ifdef CONFIG_POSIX_TIMERS
/*
* Initialize POSIX timer handling for a single task.
*/
@@ -1437,6 +1442,9 @@ static void posix_cpu_timers_init(struct task_struct *tsk)
INIT_LIST_HEAD(&tsk->cpu_timers[1]);
INIT_LIST_HEAD(&tsk->cpu_timers[2]);
}
+#else
+static inline void posix_cpu_timers_init(struct task_struct *tsk) { }
+#endif
static inline void
init_task_pid(struct task_struct *task, enum pid_type type, struct pid *pid)
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 2516b8d..a688a82 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -2246,6 +2246,7 @@ prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
}
}
+#ifdef CONFIG_POSIX_TIMERS
static void watchdog(struct rq *rq, struct task_struct *p)
{
unsigned long soft, hard;
@@ -2267,6 +2268,9 @@ static void watchdog(struct rq *rq, struct task_struct *p)
p->cputime_expires.sched_exp = p->se.sum_exec_runtime;
}
}
+#else
+static inline void watchdog(struct rq *rq, struct task_struct *p) { }
+#endif
static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
{
diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
index 34659a8..c69a9870 100644
--- a/kernel/sched/stats.h
+++ b/kernel/sched/stats.h
@@ -172,18 +172,19 @@ sched_info_switch(struct rq *rq,
*/
/**
- * cputimer_running - return true if cputimer is running
+ * get_running_cputimer - return &tsk->signal->cputimer if cputimer is running
*
* @tsk: Pointer to target task.
*/
-static inline bool cputimer_running(struct task_struct *tsk)
-
+#ifdef CONFIG_POSIX_TIMERS
+static inline
+struct thread_group_cputimer *get_running_cputimer(struct task_struct *tsk)
{
struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
/* Check if cputimer isn't running. This is accessed without locking. */
if (!READ_ONCE(cputimer->running))
- return false;
+ return NULL;
/*
* After we flush the task's sum_exec_runtime to sig->sum_sched_runtime
@@ -200,10 +201,17 @@ static inline bool cputimer_running(struct task_struct *tsk)
* clock delta is behind the expiring timer value.
*/
if (unlikely(!tsk->sighand))
- return false;
+ return NULL;
- return true;
+ return cputimer;
}
+#else
+static inline
+struct thread_group_cputimer *get_running_cputimer(struct task_struct *tsk)
+{
+ return NULL;
+}
+#endif
/**
* account_group_user_time - Maintain utime for a thread group.
@@ -218,9 +226,9 @@ static inline bool cputimer_running(struct task_struct *tsk)
static inline void account_group_user_time(struct task_struct *tsk,
cputime_t cputime)
{
- struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
+ struct thread_group_cputimer *cputimer = get_running_cputimer(tsk);
- if (!cputimer_running(tsk))
+ if (!cputimer)
return;
atomic64_add(cputime, &cputimer->cputime_atomic.utime);
@@ -239,9 +247,9 @@ 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->signal->cputimer;
+ struct thread_group_cputimer *cputimer = get_running_cputimer(tsk);
- if (!cputimer_running(tsk))
+ if (!cputimer)
return;
atomic64_add(cputime, &cputimer->cputime_atomic.stime);
@@ -260,9 +268,9 @@ 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 = &tsk->signal->cputimer;
+ struct thread_group_cputimer *cputimer = get_running_cputimer(tsk);
- if (!cputimer_running(tsk))
+ if (!cputimer)
return;
atomic64_add(ns, &cputimer->cputime_atomic.sum_exec_runtime);
