sched: sched_rt_entity

Move the task_struct members specific to rt scheduling together.
A future optimization could be to put sched_entity and sched_rt_entity
into a union.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

5 files changed, 21 insertions, 16 deletions

diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 572c65bcc80f..ee65d87bedb7 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -133,9 +133,10 @@ extern struct group_info init_groups;
         .nr_cpus_allowed = NR_CPUS,                                     \
         .mm             = NULL,                                         \
         .active_mm      = &init_mm,                                     \
-        .run_list       = LIST_HEAD_INIT(tsk.run_list),                 \
+        .rt             = {                                             \
+                .run_list       = LIST_HEAD_INIT(tsk.rt.run_list),      \
+                .time_slice     = HZ, },                                \
         .ioprio         = 0,                                            \
-        .time_slice     = HZ,                                           \
         .tasks          = LIST_HEAD_INIT(tsk.tasks),                    \
         .ptrace_children= LIST_HEAD_INIT(tsk.ptrace_children),          \
         .ptrace_list    = LIST_HEAD_INIT(tsk.ptrace_list),              \
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 72e1b8ecfbe1..a06d09ebd5c6 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -929,6 +929,11 @@ struct sched_entity {
 #endif
 };
 
+struct sched_rt_entity {
+        struct list_head run_list;
+        unsigned int time_slice;
+};
+
 struct task_struct {
         volatile long state;    /* -1 unrunnable, 0 runnable, >0 stopped */
         void *stack;
@@ -945,9 +950,9 @@ struct task_struct {
 #endif
 
         int prio, static_prio, normal_prio;
-        struct list_head run_list;
         const struct sched_class *sched_class;
         struct sched_entity se;
+        struct sched_rt_entity rt;
 
 #ifdef CONFIG_PREEMPT_NOTIFIERS
         /* list of struct preempt_notifier: */
@@ -972,7 +977,6 @@ struct task_struct {
         unsigned int policy;
         cpumask_t cpus_allowed;
         int nr_cpus_allowed;
-        unsigned int time_slice;
 
 #ifdef CONFIG_PREEMPT_RCU
         int rcu_read_lock_nesting;
diff --git a/kernel/sched.c b/kernel/sched.c
index 02d468844a91..c2cedd09d895 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1685,7 +1685,7 @@ static void __sched_fork(struct task_struct *p)
         p->se.wait_max                  = 0;
 #endif
 
-        INIT_LIST_HEAD(&p->run_list);
+        INIT_LIST_HEAD(&p->rt.run_list);
         p->se.on_rq = 0;
 
 #ifdef CONFIG_PREEMPT_NOTIFIERS
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 9affb3c9d3db..29963af782ae 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -111,7 +111,7 @@ static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)
 {
         struct rt_prio_array *array = &rq->rt.active;
 
-        list_add_tail(&p->run_list, array->queue + p->prio);
+        list_add_tail(&p->rt.run_list, array->queue + p->prio);
         __set_bit(p->prio, array->bitmap);
         inc_cpu_load(rq, p->se.load.weight);
 
@@ -127,7 +127,7 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep)
 
         update_curr_rt(rq);
 
-        list_del(&p->run_list);
+        list_del(&p->rt.run_list);
         if (list_empty(array->queue + p->prio))
                 __clear_bit(p->prio, array->bitmap);
         dec_cpu_load(rq, p->se.load.weight);
@@ -143,7 +143,7 @@ static void requeue_task_rt(struct rq *rq, struct task_struct *p)
 {
         struct rt_prio_array *array = &rq->rt.active;
 
-        list_move_tail(&p->run_list, array->queue + p->prio);
+        list_move_tail(&p->rt.run_list, array->queue + p->prio);
 }
 
 static void
@@ -212,7 +212,7 @@ static struct task_struct *pick_next_task_rt(struct rq *rq)
                 return NULL;
 
         queue = array->queue + idx;
-        next = list_entry(queue->next, struct task_struct, run_list);
+        next = list_entry(queue->next, struct task_struct, rt.run_list);
 
         next->se.exec_start = rq->clock;
 
@@ -261,14 +261,14 @@ static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu)
         queue = array->queue + idx;
         BUG_ON(list_empty(queue));
 
-        next = list_entry(queue->next, struct task_struct, run_list);
+        next = list_entry(queue->next, struct task_struct, rt.run_list);
         if (unlikely(pick_rt_task(rq, next, cpu)))
                 goto out;
 
         if (queue->next->next != queue) {
                 /* same prio task */
                 next = list_entry(queue->next->next, struct task_struct,
-                                  run_list);
+                                  rt.run_list);
                 if (pick_rt_task(rq, next, cpu))
                         goto out;
         }
@@ -282,7 +282,7 @@ static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu)
         queue = array->queue + idx;
         BUG_ON(list_empty(queue));
 
-        list_for_each_entry(next, queue, run_list) {
+        list_for_each_entry(next, queue, rt.run_list) {
                 if (pick_rt_task(rq, next, cpu))
                         goto out;
         }
@@ -846,16 +846,16 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p)
         if (p->policy != SCHED_RR)
                 return;
 
-        if (--p->time_slice)
+        if (--p->rt.time_slice)
                 return;
 
-        p->time_slice = DEF_TIMESLICE;
+        p->rt.time_slice = DEF_TIMESLICE;
 
         /*
          * Requeue to the end of queue if we are not the only element
          * on the queue:
          */
-        if (p->run_list.prev != p->run_list.next) {
+        if (p->rt.run_list.prev != p->rt.run_list.next) {
                 requeue_task_rt(rq, p);
                 set_tsk_need_resched(p);
         }
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 91a081a82f55..96473b482099 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -286,7 +286,7 @@ static void __oom_kill_task(struct task_struct *p, int verbose)
          * all the memory it needs. That way it should be able to
          * exit() and clear out its resources quickly...
          */
-        p->time_slice = HZ;
+        p->rt.time_slice = HZ;
         set_tsk_thread_flag(p, TIF_MEMDIE);
 
         force_sig(SIGKILL, p);