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authorLinus Torvalds <torvalds@linux-foundation.org>2008-10-23 09:37:16 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-23 09:37:16 -0700
commit133e887f90208d339088dd60cb1d08a72ba27288 (patch)
tree4f6bab9d13df7fac50bc7d699d8486f441deb428 /kernel/sched_fair.c
parente82cff752f57810a2259415ad2e9087c2d69484c (diff)
parent0c4b83da58ec2e96ce9c44c211d6eac5f9dae478 (diff)
Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: disable the hrtick for now sched: revert back to per-rq vruntime sched: fair scheduler should not resched rt tasks sched: optimize group load balancer sched: minor fast-path overhead reduction sched: fix the wrong mask_len, cleanup sched: kill unused scheduler decl. sched: fix the wrong mask_len sched: only update rq->clock while holding rq->lock
Diffstat (limited to 'kernel/sched_fair.c')
-rw-r--r--kernel/sched_fair.c62
1 files changed, 40 insertions, 22 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index f604dae7131..9573c33688b 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -73,6 +73,8 @@ unsigned int sysctl_sched_wakeup_granularity = 5000000UL;
const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
+static const struct sched_class fair_sched_class;
+
/**************************************************************
* CFS operations on generic schedulable entities:
*/
@@ -334,7 +336,7 @@ int sched_nr_latency_handler(struct ctl_table *table, int write,
#endif
/*
- * delta *= w / rw
+ * delta *= P[w / rw]
*/
static inline unsigned long
calc_delta_weight(unsigned long delta, struct sched_entity *se)
@@ -348,15 +350,13 @@ calc_delta_weight(unsigned long delta, struct sched_entity *se)
}
/*
- * delta *= rw / w
+ * delta /= w
*/
static inline unsigned long
calc_delta_fair(unsigned long delta, struct sched_entity *se)
{
- for_each_sched_entity(se) {
- delta = calc_delta_mine(delta,
- cfs_rq_of(se)->load.weight, &se->load);
- }
+ if (unlikely(se->load.weight != NICE_0_LOAD))
+ delta = calc_delta_mine(delta, NICE_0_LOAD, &se->load);
return delta;
}
@@ -386,26 +386,26 @@ static u64 __sched_period(unsigned long nr_running)
* We calculate the wall-time slice from the period by taking a part
* proportional to the weight.
*
- * s = p*w/rw
+ * s = p*P[w/rw]
*/
static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
- return calc_delta_weight(__sched_period(cfs_rq->nr_running), se);
+ unsigned long nr_running = cfs_rq->nr_running;
+
+ if (unlikely(!se->on_rq))
+ nr_running++;
+
+ return calc_delta_weight(__sched_period(nr_running), se);
}
/*
* We calculate the vruntime slice of a to be inserted task
*
- * vs = s*rw/w = p
+ * vs = s/w
*/
-static u64 sched_vslice_add(struct cfs_rq *cfs_rq, struct sched_entity *se)
+static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
- unsigned long nr_running = cfs_rq->nr_running;
-
- if (!se->on_rq)
- nr_running++;
-
- return __sched_period(nr_running);
+ return calc_delta_fair(sched_slice(cfs_rq, se), se);
}
/*
@@ -628,7 +628,7 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
* stays open at the end.
*/
if (initial && sched_feat(START_DEBIT))
- vruntime += sched_vslice_add(cfs_rq, se);
+ vruntime += sched_vslice(cfs_rq, se);
if (!initial) {
/* sleeps upto a single latency don't count. */
@@ -748,7 +748,7 @@ pick_next(struct cfs_rq *cfs_rq, struct sched_entity *se)
struct rq *rq = rq_of(cfs_rq);
u64 pair_slice = rq->clock - cfs_rq->pair_start;
- if (!cfs_rq->next || pair_slice > sched_slice(cfs_rq, cfs_rq->next)) {
+ if (!cfs_rq->next || pair_slice > sysctl_sched_min_granularity) {
cfs_rq->pair_start = rq->clock;
return se;
}
@@ -849,11 +849,31 @@ static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
hrtick_start(rq, delta);
}
}
+
+/*
+ * called from enqueue/dequeue and updates the hrtick when the
+ * current task is from our class and nr_running is low enough
+ * to matter.
+ */
+static void hrtick_update(struct rq *rq)
+{
+ struct task_struct *curr = rq->curr;
+
+ if (curr->sched_class != &fair_sched_class)
+ return;
+
+ if (cfs_rq_of(&curr->se)->nr_running < sched_nr_latency)
+ hrtick_start_fair(rq, curr);
+}
#else /* !CONFIG_SCHED_HRTICK */
static inline void
hrtick_start_fair(struct rq *rq, struct task_struct *p)
{
}
+
+static inline void hrtick_update(struct rq *rq)
+{
+}
#endif
/*
@@ -874,7 +894,7 @@ static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup)
wakeup = 1;
}
- hrtick_start_fair(rq, rq->curr);
+ hrtick_update(rq);
}
/*
@@ -896,7 +916,7 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep)
sleep = 1;
}
- hrtick_start_fair(rq, rq->curr);
+ hrtick_update(rq);
}
/*
@@ -1002,8 +1022,6 @@ static inline int wake_idle(int cpu, struct task_struct *p)
#ifdef CONFIG_SMP
-static const struct sched_class fair_sched_class;
-
#ifdef CONFIG_FAIR_GROUP_SCHED
/*
* effective_load() calculates the load change as seen from the root_task_group