From: Chris Redpath <chris.redpath@arm.com>
Date: Mon, 22 Jul 2013 14:56:28 +0000 (+0100)
Subject: HMP: Access runqueue task clocks directly.
X-Git-Tag: firefly_0821_release~3680^2~16^2^2~43
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=0d520ee8d4e910d1400e1b21608aff3bbce7ad6f;p=firefly-linux-kernel-4.4.55.git

HMP: Access runqueue task clocks directly.

Avoids accesses through cfs_rq going bad when the cpu_rq doesn't
have a cfs member.

Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
---

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index afd76bf9433f..bfd27e89399a 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3769,8 +3769,8 @@ static inline unsigned int hmp_select_slower_cpu(struct task_struct *tsk,
 
 static inline void hmp_next_up_delay(struct sched_entity *se, int cpu)
 {
-	struct cfs_rq *cfs_rq = &cpu_rq(cpu)->cfs;
-	u64 now = cfs_rq_clock_task(cfs_rq);
+	/* hack - always use clock from first online CPU */
+	u64 now = cpu_rq(cpumask_first(cpu_online_mask))->clock_task;
 	se->avg.hmp_last_up_migration = now;
 	se->avg.hmp_last_down_migration = 0;
 	cpu_rq(cpu)->avg.hmp_last_up_migration = now;
@@ -3779,8 +3779,8 @@ static inline void hmp_next_up_delay(struct sched_entity *se, int cpu)
 
 static inline void hmp_next_down_delay(struct sched_entity *se, int cpu)
 {
-	struct cfs_rq *cfs_rq = &cpu_rq(cpu)->cfs;
-	u64 now = cfs_rq_clock_task(cfs_rq);
+	/* hack - always use clock from first online CPU */
+	u64 now = cpu_rq(cpumask_first(cpu_online_mask))->clock_task;
 	se->avg.hmp_last_down_migration = now;
 	se->avg.hmp_last_up_migration = 0;
 	cpu_rq(cpu)->avg.hmp_last_down_migration = now;
@@ -6481,7 +6481,6 @@ static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) { }
 static unsigned int hmp_up_migration(int cpu, int *target_cpu, struct sched_entity *se)
 {
 	struct task_struct *p = task_of(se);
-	struct cfs_rq *cfs_rq = &cpu_rq(cpu)->cfs;
 	u64 now;
 
 	if (target_cpu)
@@ -6499,7 +6498,8 @@ static unsigned int hmp_up_migration(int cpu, int *target_cpu, struct sched_enti
 		return 0;
 
 	/* Let the task load settle before doing another up migration */
-	now = cfs_rq_clock_task(cfs_rq);
+	/* hack - always use clock from first online CPU */
+	now = cpu_rq(cpumask_first(cpu_online_mask))->clock_task;
 	if (((now - se->avg.hmp_last_up_migration) >> 10)
 					< hmp_next_up_threshold)
 		return 0;
@@ -6522,7 +6522,6 @@ static unsigned int hmp_up_migration(int cpu, int *target_cpu, struct sched_enti
 static unsigned int hmp_down_migration(int cpu, struct sched_entity *se)
 {
 	struct task_struct *p = task_of(se);
-	struct cfs_rq *cfs_rq = &cpu_rq(cpu)->cfs;
 	u64 now;
 
 	if (hmp_cpu_is_slowest(cpu))
@@ -6538,7 +6537,8 @@ static unsigned int hmp_down_migration(int cpu, struct sched_entity *se)
 #endif
 
 	/* Let the task load settle before doing another down migration */
-	now = cfs_rq_clock_task(cfs_rq);
+	/* hack - always use clock from first online CPU */
+	now = cpu_rq(cpumask_first(cpu_online_mask))->clock_task;
 	if (((now - se->avg.hmp_last_down_migration) >> 10)
 					< hmp_next_down_threshold)
 		return 0;