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[PATCH] sched: extract load calculation from rebalance_tick 

A load calculation is always done in rebalance_tick() in addition to the real
load balancing activities that only take place when certain jiffie counts have
been reached.  Move that processing into a separate function and call it
directly from scheduler_tick().

Also extract the time slice handling from scheduler_tick and put it into a
separate function.  Then we can clean up scheduler_tick significantly.  It
will no longer have any gotos.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Peter Williams <pwil3058@bigpond.net.au>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Christoph Lameter 2006-12-10 02:20:22 -08:00 committed by Linus Torvalds
parent fe2eea3faf
commit 7835b98bc6
1 changed files with 54 additions and 42 deletions
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96
kernel/sched.c
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@ -2833,20 +2833,9 @@ static void active_load_balance(struct rq *busiest_rq, int busiest_cpu)
spin_unlock(&target_rq->lock);
}
/*
* rebalance_tick will get called every timer tick, on every CPU.
*
* It checks each scheduling domain to see if it is due to be balanced,
* and initiates a balancing operation if so.
*
* Balancing parameters are set up in arch_init_sched_domains.
*/
static void
rebalance_tick(int this_cpu, struct rq *this_rq, enum idle_type idle)
static void update_load(struct rq *this_rq)
{
unsigned long this_load, interval;
struct sched_domain *sd;
unsigned long this_load;
int i, scale;
this_load = this_rq->raw_weighted_load;
@ -2866,6 +2855,22 @@ rebalance_tick(int this_cpu, struct rq *this_rq, enum idle_type idle)
new_load += scale-1;
this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) / scale;
}
}
/*
* rebalance_tick will get called every timer tick, on every CPU.
*
* It checks each scheduling domain to see if it is due to be balanced,
* and initiates a balancing operation if so.
*
* Balancing parameters are set up in arch_init_sched_domains.
*/
static void
rebalance_tick(int this_cpu, struct rq *this_rq, enum idle_type idle)
{
unsigned long interval;
struct sched_domain *sd;
for_each_domain(this_cpu, sd) {
if (!(sd->flags & SD_LOAD_BALANCE))
@ -2897,12 +2902,15 @@ rebalance_tick(int this_cpu, struct rq *this_rq, enum idle_type idle)
/*
* on UP we do not need to balance between CPUs:
*/
static inline void rebalance_tick(int cpu, struct rq *rq, enum idle_type idle)
static inline void rebalance_tick(int cpu, struct rq *rq)
{
}
static inline void idle_balance(int cpu, struct rq *rq)
{
}
static inline void update_load(struct rq *this_rq)
{
}
#endif
static inline int wake_priority_sleeper(struct rq *rq)
@ -3052,35 +3060,12 @@ void account_steal_time(struct task_struct *p, cputime_t steal)
cpustat->steal = cputime64_add(cpustat->steal, tmp);
}
/*
* This function gets called by the timer code, with HZ frequency.
* We call it with interrupts disabled.
*
* It also gets called by the fork code, when changing the parent's
* timeslices.
*/
void scheduler_tick(void)
static void task_running_tick(struct rq *rq, struct task_struct *p)
{
unsigned long long now = sched_clock();
struct task_struct *p = current;
int cpu = smp_processor_id();
struct rq *rq = cpu_rq(cpu);
update_cpu_clock(p, rq, now);
rq->timestamp_last_tick = now;
if (p == rq->idle) {
if (wake_priority_sleeper(rq))
goto out;
rebalance_tick(cpu, rq, SCHED_IDLE);
return;
}
/* Task might have expired already, but not scheduled off yet */
if (p->array != rq->active) {
/* Task has expired but was not scheduled yet */
set_tsk_need_resched(p);
goto out;
return;
}
spin_lock(&rq->lock);
/*
@ -3148,8 +3133,35 @@ void scheduler_tick(void)
}
out_unlock:
spin_unlock(&rq->lock);
out:
rebalance_tick(cpu, rq, NOT_IDLE);
}
/*
* This function gets called by the timer code, with HZ frequency.
* We call it with interrupts disabled.
*
* It also gets called by the fork code, when changing the parent's
* timeslices.
*/
void scheduler_tick(void)
{
unsigned long long now = sched_clock();
struct task_struct *p = current;
int cpu = smp_processor_id();
struct rq *rq = cpu_rq(cpu);
enum idle_type idle = NOT_IDLE;
update_cpu_clock(p, rq, now);
rq->timestamp_last_tick = now;
if (p == rq->idle) {
/* Task on the idle queue */
if (!wake_priority_sleeper(rq))
idle = SCHED_IDLE;
} else
task_running_tick(rq, p);
update_load(rq);
rebalance_tick(cpu, rq, idle);
}
#ifdef CONFIG_SCHED_SMT