Long running entities that do not block (dequeue) require periodic updates to
maintain accurate share values. (Note: group entities with several threads are
quite likely to be non-blocking in many circumstances).
By virtue of being long-running however, we will see entity ticks (otherwise
the required update occurs in dequeue/put and we are done). Thus we can move
the detection (and associated work) for these updates into the periodic path.
This restores the 'atomicity' of update_curr() with respect to accounting.
Signed-off-by: Paul Turner <pjt@google.com>
---
kernel/sched_fair.c | 29 ++++++++++++++++++++++++-----
1 file changed, 24 insertions(+), 5 deletions(-)
Index: tip3/kernel/sched_fair.c
===================================================================
--- tip3.orig/kernel/sched_fair.c
+++ tip3/kernel/sched_fair.c
@@ -563,12 +563,10 @@ __update_curr(struct cfs_rq *cfs_rq, str
update_min_vruntime(cfs_rq);
#if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED
- cfs_rq->load_unacc_exec_time += delta_exec;
- if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {
- update_cfs_load(cfs_rq, 0);
- update_cfs_shares(cfs_rq, 0);
- }
+ if (!entity_is_task(curr))
+ group_cfs_rq(curr)->load_unacc_exec_time += delta_exec;
#endif
+
}
static void update_curr(struct cfs_rq *cfs_rq)
@@ -809,6 +807,20 @@ static void update_cfs_shares(struct cfs
reweight_entity(cfs_rq_of(se), se, shares);
}
+
+static void update_entity_shares_tick(struct sched_entity *se)
+{
+ struct cfs_rq *cfs_rq;
+
+ if (entity_is_task(se))
+ return;
+
+ cfs_rq = group_cfs_rq(se);
+ if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {
+ update_cfs_load(cfs_rq, 0);
+ update_cfs_shares(cfs_rq, 0);
+ }
+}
#else /* CONFIG_FAIR_GROUP_SCHED */
static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
{
@@ -1133,6 +1145,13 @@ entity_tick(struct cfs_rq *cfs_rq, struc
*/
update_curr(cfs_rq);
+#if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED
+ /*
+ * Update share accounting for long-running entities.
+ */
+ update_entity_shares_tick(curr);
+#endif
+
#ifdef CONFIG_SCHED_HRTICK
/*
* queued ticks are scheduled to match the slice, so don't bother
--
