Adding dont_balance bool into struct sched_entity,
to mark tasks which are rebalanced based on affinity.
It's used only when REBALANCE_AFFINITY feature is
switched on. The code functionality of this feature
is introduced in following patch.
Signed-off-by: Jiri Olsa <jo...@kernel.org>
---
include/linux/sched.h | 2 ++
kernel/sched/fair.c | 21 ++++++++++++++++++---
kernel/sched/features.h | 1 +
3 files changed, 21 insertions(+), 3 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index dee41bf59e6b..0e6ac882283b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1331,6 +1331,8 @@ struct sched_entity {
u64 nr_migrations;
+ bool dont_balance;
+
#ifdef CONFIG_SCHEDSTATS
struct sched_statistics statistics;
#endif
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c6dd8bab010c..f19c9435c64d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -900,6 +900,11 @@ update_stats_curr_start(struct cfs_rq *cfs_rq, struct
sched_entity *se)
se->exec_start = rq_clock_task(rq_of(cfs_rq));
}
+static bool dont_balance(struct task_struct *p)
+{
+ return sched_feat(REBALANCE_AFFINITY) && p->se.dont_balance;
+}
+
/**************************************************
* Scheduling class queueing methods:
*/
@@ -2172,6 +2177,10 @@ void task_numa_fault(int last_cpupid, int mem_node, int
pages, int flags)
if (!static_branch_likely(&sched_numa_balancing))
return;
+ /* Don't move task if the affinity balance is active. */
+ if (dont_balance(p))
+ return;
+
/* for example, ksmd faulting in a user's mm */
if (!p->mm)
return;
@@ -3387,6 +3396,8 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity
*se, int flags)
update_min_vruntime(cfs_rq);
update_cfs_shares(cfs_rq);
+
+ se->dont_balance = false;
}
/*
@@ -6017,13 +6028,17 @@ int can_migrate_task(struct task_struct *p, struct
lb_env *env)
/*
* We do not migrate tasks that are:
* 1) throttled_lb_pair, or
- * 2) cannot be migrated to this CPU due to cpus_allowed, or
- * 3) running (obviously), or
- * 4) are cache-hot on their current CPU.
+ * 2) dont_balance is set, or
+ * 3) cannot be migrated to this CPU due to cpus_allowed, or
+ * 4) running (obviously), or
+ * 5) are cache-hot on their current CPU.
*/
if (throttled_lb_pair(task_group(p), env->src_cpu, env->dst_cpu))
return 0;
+ if (dont_balance(p))
+ return 0;
+
if (!cpumask_test_cpu(env->dst_cpu, tsk_cpus_allowed(p))) {
int cpu;
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index 69631fa46c2f..acdd78a6be4d 100644
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -68,4 +68,5 @@ SCHED_FEAT(FORCE_SD_OVERLAP, false)
SCHED_FEAT(RT_RUNTIME_SHARE, true)
SCHED_FEAT(LB_MIN, false)
SCHED_FEAT(ATTACH_AGE_LOAD, true)
+SCHED_FEAT(REBALANCE_AFFINITY, false)
--
2.4.11
