sched: group scheduling, change how cpu load is calculated

This patch changes how the cpu load exerted by fair_sched_class tasks
is calculated. Load exerted by fair_sched_class tasks on a cpu is now
a summation of the group weights, rather than summation of task weights.
Weight exerted by a group on a cpu is dependent on the shares allocated
to it.

This version of patch has a minor impact on code size, but should have
no runtime/functional impact for !CONFIG_FAIR_GROUP_SCHED.

Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/sched.c b/kernel/sched.c
index cfa6958..c915f3e 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -886,6 +886,16 @@ static void cpuacct_charge(struct task_struct *tsk, u64 cputime);
 static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
 #endif
 
+static inline void inc_cpu_load(struct rq *rq, unsigned long load)
+{
+       update_load_add(&rq->load, load);
+}
+
+static inline void dec_cpu_load(struct rq *rq, unsigned long load)
+{
+       update_load_sub(&rq->load, load);
+}
+
 #include "sched_stats.h"
 #include "sched_idletask.c"
 #include "sched_fair.c"
@@ -896,26 +906,14 @@ static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
 
 #define sched_class_highest (&rt_sched_class)
 
-static inline void inc_load(struct rq *rq, const struct task_struct *p)
-{
-       update_load_add(&rq->load, p->se.load.weight);
-}
-
-static inline void dec_load(struct rq *rq, const struct task_struct *p)
-{
-       update_load_sub(&rq->load, p->se.load.weight);
-}
-
 static void inc_nr_running(struct task_struct *p, struct rq *rq)
 {
        rq->nr_running++;
-       inc_load(rq, p);
 }
 
 static void dec_nr_running(struct task_struct *p, struct rq *rq)
 {
        rq->nr_running--;
-       dec_load(rq, p);
 }
 
 static void set_load_weight(struct task_struct *p)
@@ -4087,10 +4085,8 @@ void set_user_nice(struct task_struct *p, long nice)
                goto out_unlock;
        }
        on_rq = p->se.on_rq;
-       if (on_rq) {
+       if (on_rq)
                dequeue_task(rq, p, 0);
-               dec_load(rq, p);
-       }
 
        p->static_prio = NICE_TO_PRIO(nice);
        set_load_weight(p);
@@ -4100,7 +4096,6 @@ void set_user_nice(struct task_struct *p, long nice)
 
        if (on_rq) {
                enqueue_task(rq, p, 0);
-               inc_load(rq, p);
                /*
                 * If the task increased its priority or is running and
                 * lowered its priority, then reschedule its CPU:

diff --cc kernel/sched_fair.c
Simple merge

diff --cc kernel/sched_rt.c
Simple merge