Commit 2cb8600e authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar

sched: documentation: place_entity() comments

Add a few comments to place_entity(). No code changed.
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 10b77724
......@@ -473,19 +473,26 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
} else if (sched_feat(APPROX_AVG) && cfs_rq->nr_running)
vruntime += sched_vslice(cfs_rq)/2;
/*
* The 'current' period is already promised to the current tasks,
* however the extra weight of the new task will slow them down a
* little, place the new task so that it fits in the slot that
* stays open at the end.
*/
if (initial && sched_feat(START_DEBIT))
vruntime += sched_vslice_add(cfs_rq, se);
if (!initial) {
/* sleeps upto a single latency don't count. */
if (sched_feat(NEW_FAIR_SLEEPERS) && entity_is_task(se) &&
task_of(se)->policy != SCHED_BATCH)
vruntime -= sysctl_sched_latency;
vruntime = max_t(s64, vruntime, se->vruntime);
/* ensure we never gain time by being placed backwards. */
vruntime = max_vruntime(se->vruntime, vruntime);
}
se->vruntime = vruntime;
}
static void
......
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