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Commit 5d2b3d36 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

sched: fix sleeper bonus 



Peter Ziljstra noticed that the sleeper bonus deduction code
was not properly rate-limited: a task that scheduled more
frequently would get a disproportionately large deduction.
So limit the deduction to delta_exec.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 6707de00

kernel/sched_fair.c

+6 −6
Original line number Diff line number Diff line
@@ -75,7 +75,7 @@ enum { 


unsigned int sysctl_sched_features __read_mostly =

		SCHED_FEAT_FAIR_SLEEPERS	*1 |

		SCHED_FEAT_SLEEPER_AVG		*1 |

		SCHED_FEAT_SLEEPER_AVG		*0 |

		SCHED_FEAT_SLEEPER_LOAD_AVG	*1 |

		SCHED_FEAT_PRECISE_CPU_LOAD	*1 |

		SCHED_FEAT_START_DEBIT		*1 |
@@ -304,11 +304,9 @@ __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr) 
	delta_mine = calc_delta_mine(delta_exec, curr->load.weight, lw);



	if (cfs_rq->sleeper_bonus > sysctl_sched_granularity) {

		delta = calc_delta_mine(cfs_rq->sleeper_bonus,

					curr->load.weight, lw);

		if (unlikely(delta > cfs_rq->sleeper_bonus))

			delta = cfs_rq->sleeper_bonus;



		delta = min(cfs_rq->sleeper_bonus, (u64)delta_exec);

		delta = calc_delta_mine(delta, curr->load.weight, lw);

		delta = min((u64)delta, cfs_rq->sleeper_bonus);

		cfs_rq->sleeper_bonus -= delta;

		delta_mine -= delta;

	}
@@ -521,6 +519,8 @@ static void __enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) 
	 * Track the amount of bonus we've given to sleepers:

	 */

	cfs_rq->sleeper_bonus += delta_fair;

	if (unlikely(cfs_rq->sleeper_bonus > sysctl_sched_runtime_limit))

		cfs_rq->sleeper_bonus = sysctl_sched_runtime_limit;



	schedstat_add(cfs_rq, wait_runtime, se->wait_runtime);

}