Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751018AbdGMCZA (ORCPT ); Wed, 12 Jul 2017 22:25:00 -0400 Received: from mail-pg0-f45.google.com ([74.125.83.45]:34528 "EHLO mail-pg0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750755AbdGMCY6 (ORCPT ); Wed, 12 Jul 2017 22:24:58 -0400 From: Joel Fernandes To: linux-kernel@vger.kernel.org Cc: Juri Lelli , Daniel Bristot de Oliveira , Joel Fernandes , Peter Zijlstra , Ingo Molnar Subject: [PATCH RESEND] sched: deadline: Fix confusing comments about selection of top pi-waiter Date: Wed, 12 Jul 2017 19:24:29 -0700 Message-Id: <20170713022429.10307-1-joelaf@google.com> X-Mailer: git-send-email 2.13.2.932.g7449e964c-goog Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2062 Lines: 46 This comment in the code is incomplete, and I believe it begs a definition of dl_boosted to make sense of the condition that follows. Rewrite the comment and also rearrange the condition that follows to reflect the first condition "we have a top pi-waiter which is a SCHED_DEADLINE task" in that order. Also fix a typo that follows. Cc: Peter Zijlstra Signed-off-by: Joel Fernandes Acked-by: Juri Lelli Reviewed-by: Daniel Bristot de Oliveira --- kernel/sched/deadline.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index a2ce59015642..61c56d903918 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -970,17 +970,19 @@ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags) struct sched_dl_entity *pi_se = &p->dl; /* - * Use the scheduling parameters of the top pi-waiter - * task if we have one and its (absolute) deadline is - * smaller than our one... OTW we keep our runtime and - * deadline. + * Use the scheduling parameters of the top pi-waiter task if: + * - we have a top pi-waiter which is a SCHED_DEADLINE task AND + * - our dl_boosted is set (i.e. the pi-waiter's (absolute) deadline is + * smaller than our deadline OR we are a !SCHED_DEADLINE task getting + * boosted due to a SCHED_DEADLINE pi-waiter). + * Otherwise we keep our runtime and deadline. */ - if (pi_task && p->dl.dl_boosted && dl_prio(pi_task->normal_prio)) { + if (pi_task && dl_prio(pi_task->normal_prio) && p->dl.dl_boosted) { pi_se = &pi_task->dl; } else if (!dl_prio(p->normal_prio)) { /* * Special case in which we have a !SCHED_DEADLINE task - * that is going to be deboosted, but exceedes its + * that is going to be deboosted, but exceeds its * runtime while doing so. No point in replenishing * it, as it's going to return back to its original * scheduling class after this. -- 2.13.2.932.g7449e964c-goog