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authorChristoph Lameter <clameter@sgi.com>2006-12-10 02:20:22 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-10 09:55:42 -0800
commit7835b98bc6de2ca10afa45572d272304b000b048 (patch)
tree6c029f271821b00d18f5f318526b80511b409838 /kernel
parentfe2eea3fafb3df2f5b8a55a48bcbb0d23b3b5618 (diff)
[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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched.c96
1 files changed, 54 insertions, 42 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index d327511d268..3c1b74aa1b0 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -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