linux-kernel - [RFC PATCH V2 0/3] sched/fair: Fix nr-running vs delayed-dequeue

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Message-ID: <20250303105241.17251-1-xuewen.yan@unisoc.com>
Date: Mon, 3 Mar 2025 18:52:38 +0800
From: Xuewen Yan <xuewen.yan@...soc.com>
To: <vincent.guittot@...aro.org>, <peterz@...radead.org>, <mingo@...hat.com>,
        <juri.lelli@...hat.com>, <dietmar.eggemann@....com>,
        <rostedt@...dmis.org>, <bsegall@...gle.com>, <mgorman@...e.de>,
        <vschneid@...hat.com>
CC: <linux-kernel@...r.kernel.org>, <ke.wang@...soc.com>, <di.shen@...soc.com>,
        <xuewen.yan94@...il.com>
Subject: [RFC PATCH V2 0/3] sched/fair: Fix nr-running vs delayed-dequeue

Delayed dequeued feature keeps a sleeping sched_entitiy enqueued until its
lag has elapsed. As a result, it stays also visible in rq->nr_running.
However, sometimes when using nr-running, we should not consider
sched-delayed tasks.
This serie fixes those by adding a helper function which return the
number of sched-delayed tasks. And when we should get the real runnable
tasks, we sub the nr-delayed tasks.

Changes sinc v1:
- add cover-letter
- add helper function;
- add more fixes

Xuewen Yan (3):
  sched/fair: Fixup-wake_up_sync-vs-DELAYED_DEQUEUE
  sched/fair: Do not consider the sched-delayed task when yield
  sched: Do not consider the delayed task when cpu is about to enter
    idle

 kernel/sched/core.c  |  2 +-
 kernel/sched/fair.c  | 10 +++++++---
 kernel/sched/sched.h |  5 +++++
 3 files changed, 13 insertions(+), 4 deletions(-)

-- 
2.25.1