diff options
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 48633a1c3b46..445bcd2d7ee1 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3254,6 +3254,37 @@ static inline void check_schedstat_required(void) #endif } + +/* + * MIGRATION + * + * dequeue + * update_curr() + * update_min_vruntime() + * vruntime -= min_vruntime + * + * enqueue + * update_curr() + * update_min_vruntime() + * vruntime += min_vruntime + * + * this way the vruntime transition between RQs is done when both + * min_vruntime are up-to-date. + * + * WAKEUP (remote) + * + * ->task_waking_fair() + * vruntime -= min_vruntime + * + * enqueue + * update_curr() + * update_min_vruntime() + * vruntime += min_vruntime + * + * this way we don't have the most up-to-date min_vruntime on the originating + * CPU and an up-to-date min_vruntime on the destination CPU. + */ + static void enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) { @@ -4810,6 +4841,12 @@ static unsigned long cpu_avg_load_per_task(int cpu) return 0; } +/* + * Called to migrate a waking task; as blocked tasks retain absolute vruntime + * the migration needs to deal with this by subtracting the old and adding the + * new min_vruntime -- the latter is done by enqueue_entity() when placing + * the task on the new runqueue. + */ static void task_waking_fair(struct task_struct *p) { struct sched_entity *se = &p->se; |