linux-kernel - [PATCH 09/15] sched,fair: add helper functions for flattened runqueue

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Message-Id: <20190906191237.27006-10-riel@surriel.com>
Date:   Fri,  6 Sep 2019 15:12:31 -0400
From:   Rik van Riel <riel@...riel.com>
To:     linux-kernel@...r.kernel.org
Cc:     kernel-team@...com, pjt@...gle.com, dietmar.eggemann@....com,
        peterz@...radead.org, mingo@...hat.com, morten.rasmussen@....com,
        tglx@...utronix.de, mgorman@...hsingularity.net,
        vincent.guittot@...aro.org, Rik van Riel <riel@...riel.com>
Subject: [PATCH 09/15] sched,fair: add helper functions for flattened runqueue

Add helper functions to make the flattened runqueue patch a little smaller.

The task_se_h_weight function is similar to task_se_h_load, but scales the
task weight by the group weight, without taking the task's duty cycle into
account.

The task_se_in_cgroup helper is functionally identical to parent_entity,
but directly calling a function with that name obscures what the other
code is trying to use it for, and would make the code harder to understand.

Signed-off-by: Rik van Riel <riel@...riel.com>
---
 kernel/sched/fair.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 3e294e9c9994..08f7f627bdde 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -243,6 +243,7 @@ static u64 __calc_delta(u64 delta_exec, unsigned long weight, struct load_weight
 
 const struct sched_class fair_sched_class;
 static unsigned long task_se_h_load(struct sched_entity *se);
+static unsigned long task_se_h_weight(struct sched_entity *se);
 
 /**************************************************************
  * CFS operations on generic schedulable entities:
@@ -431,6 +432,12 @@ static inline struct sched_entity *parent_entity(struct sched_entity *se)
 	return se->parent;
 }
 
+/* Is this (task) sched_entity in a non-root cgroup? */
+static inline bool task_se_in_cgroup(struct sched_entity *se)
+{
+	return parent_entity(se);
+}
+
 static void
 find_matching_se(struct sched_entity **se, struct sched_entity **pse)
 {
@@ -513,6 +520,11 @@ static inline struct sched_entity *parent_entity(struct sched_entity *se)
 	return NULL;
 }
 
+static inline bool task_se_in_cgroup(struct sched_entity *se)
+{
+	return false;
+}
+
 static inline void
 find_matching_se(struct sched_entity **se, struct sched_entity **pse)
 {
@@ -7853,6 +7865,20 @@ static void update_cfs_rq_h_load(struct cfs_rq *cfs_rq)
 	}
 }
 
+static unsigned long task_se_h_weight(struct sched_entity *se)
+{
+	struct cfs_rq *cfs_rq;
+
+	if (!task_se_in_cgroup(se))
+		return se->load.weight;
+
+	cfs_rq = group_cfs_rq_of_parent(se);
+	update_cfs_rq_h_load(cfs_rq);
+
+	/* Reduce the load.weight by the h_load of the group the task is in. */
+	return (cfs_rq->h_load * se->load.weight) >> SCHED_FIXEDPOINT_SHIFT;
+}
+
 static unsigned long task_se_h_load(struct sched_entity *se)
 {
 	struct cfs_rq *cfs_rq = group_cfs_rq_of_parent(se);
@@ -7889,6 +7915,11 @@ static unsigned long task_se_h_load(struct sched_entity *se)
 {
 	return se->avg.load_avg;
 }
+
+static unsigned long task_se_h_weight(struct sched_entity *se)
+{
+	return se->load.weight;
+}
 #endif
 
 /********** Helpers for find_busiest_group ************************/
-- 
2.20.1