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authorSrinath Sridharan <srinathsr@google.com>2016-07-29 17:50:11 +0100
committerAmit Pundir <amit.pundir@linaro.org>2016-09-14 15:02:22 +0530
commitbfa1dd2bfda910b60e425974fd5dc94a6bdaccc4 (patch)
tree555657db09f2d434dbcc0852486fb458eb8bdbad
parente86992e170b0abb448b1b612fc7a1f08f2809bed (diff)
sched/fair: Favor higher cpus only for boosted tasks
This CL separates the notion of boost and prefer_idle schedtune attributes in cpu selection. Today only top-app tasks are boosted. The CPU selection is slightly tweaked such that higher order cpus are preferred only for boosted tasks (top-app) and the rest would be skewed towards lower order cpus. This avoids starvation issues for fg tasks when interacting with high priority top-app tasks (a problem often seen in the case of system_server). bug: 30245369 bug: 30292998 Change-Id: I0377e00893b9f6586eec55632a265518fd2fa8a1 Conflicts: kernel/sched/fair.c
-rw-r--r--kernel/sched/fair.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 88eae79d1a3c..e7f9afe29c61 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5612,7 +5612,7 @@ done:
return target;
}
-static inline int find_best_target(struct task_struct *p, bool prefer_idle)
+static inline int find_best_target(struct task_struct *p, bool boosted, bool prefer_idle)
{
int iter_cpu;
int target_cpu = -1;
@@ -5630,9 +5630,9 @@ static inline int find_best_target(struct task_struct *p, bool prefer_idle)
int idle_idx;
/*
- * favor higher cpus for tasks that prefer idle cores
+ * Iterate from higher cpus for boosted tasks.
*/
- int i = prefer_idle ? NR_CPUS-iter_cpu-1 : iter_cpu;
+ int i = boosted ? NR_CPUS-iter_cpu-1 : iter_cpu;
if (!cpu_online(i) || !cpumask_test_cpu(i, tsk_cpus_allowed(p)))
continue;
@@ -5802,7 +5802,7 @@ static int energy_aware_wake_cpu(struct task_struct *p, int target, int sync)
bool boosted = 0;
bool prefer_idle = 0;
#endif
- int tmp_target = find_best_target(p, boosted || prefer_idle);
+ int tmp_target = find_best_target(p, boosted, prefer_idle);
if (tmp_target >= 0) {
target_cpu = tmp_target;
if ((boosted || prefer_idle) && idle_cpu(target_cpu))