lkml.org 
[lkml]   [2012]   [Jun]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH 16/16] sched: introduce temporary FAIR_GROUP_SCHED dependency for load-tracking
From
Date
While per-entity load-tracking is generally useful, beyond computing shares
distribution, e.g.
runnable based load-balance (in progress), governors, power-management, etc

These facilities are not yet consumers of this data. This may be trivially
reverted when the information is required; but avoid paying the overhead for
calculations we will not use until then.

Signed-off-by: Paul Turner <pjt@google.com>
---
include/linux/sched.h | 8 +++++++-
kernel/sched/fair.c | 14 +++++++++++---
kernel/sched/sched.h | 9 ++++++++-
3 files changed, 26 insertions(+), 5 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index a65c097..7c0c72d 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1205,7 +1205,13 @@ struct sched_entity {
/* rq "owned" by this entity/group: */
struct cfs_rq *my_q;
#endif
-#ifdef CONFIG_SMP
+/*
+ * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be
+ * removed when useful for applications beyond shares distribution (e.g.
+ * load-balance).
+ */
+#if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)
+ /* Per-entity load-tracking */
struct sched_avg avg;
#endif
};
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 3d1aaa8..0b6e2df 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -882,7 +882,8 @@ static inline void update_cfs_shares(struct cfs_rq *cfs_rq)
}
#endif /* CONFIG_FAIR_GROUP_SCHED */

-#ifdef CONFIG_SMP
+/* Only depends on SMP, FAIR_GROUP_SCHED may be removed when useful in lb */
+#if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)
/*
* We choose a half-life close to 1 scheduling period.
* Note: The tables below are dependent on this value.
@@ -3214,6 +3215,12 @@ unlock:
}

/*
+ * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be
+ * removed when useful for applications beyond shares distribution (e.g.
+ * load-balance).
+ */
+#ifdef CONFIG_FAIR_GROUP_SCHED
+/*
* Called immediately before a task is migrated to a new cpu; task_cpu(p) and
* cfs_rq_of(p) references at time of call are still valid and identify the
* previous cpu. However, the caller only guarantees p->pi_lock is held; no
@@ -3235,7 +3242,7 @@ migrate_task_rq_fair(struct task_struct *p, int next_cpu) {
atomic64_add(se->avg.load_avg_contrib, &cfs_rq->removed_load);
}
}
-
+#endif

#endif /* CONFIG_SMP */

@@ -5927,8 +5934,9 @@ const struct sched_class fair_sched_class = {

#ifdef CONFIG_SMP
.select_task_rq = select_task_rq_fair,
+#ifdef CONFIG_FAIR_GROUP_SCHED
.migrate_task_rq = migrate_task_rq_fair,
-
+#endif
.rq_online = rq_online_fair,
.rq_offline = rq_offline_fair,

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index bb76895..d920943 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -225,6 +225,12 @@ struct cfs_rq {
#endif

#ifdef CONFIG_SMP
+/*
+ * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be
+ * removed when useful for applications beyond shares distribution (e.g.
+ * load-balance).
+ */
+#ifdef CONFIG_FAIR_GROUP_SCHED
/*
* CFS Load tracking
* Under CFS, load is tracked on a per-entity basis and aggregated up.
@@ -234,7 +240,8 @@ struct cfs_rq {
u64 runnable_load_avg, blocked_load_avg;
atomic64_t decay_counter, removed_load;
u64 last_decay;
-
+#endif /* CONFIG_FAIR_GROUP_SCHED */
+/* These always depend on CONFIG_FAIR_GROUP_SCHED */
#ifdef CONFIG_FAIR_GROUP_SCHED
u32 tg_runnable_contrib, tg_usage_contrib;
u64 tg_load_contrib;



\
 
 \ /
  Last update: 2012-06-28 06:42    [from the cache]
©2003-2011 Jasper Spaans