From nobody Thu Apr 2 19:53:08 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 795CAC32771 for ; Wed, 21 Sep 2022 08:12:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229678AbiIUIMg (ORCPT ); Wed, 21 Sep 2022 04:12:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53684 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229587AbiIUIMc (ORCPT ); Wed, 21 Sep 2022 04:12:32 -0400 Received: from mail-yb1-xb2b.google.com (mail-yb1-xb2b.google.com [IPv6:2607:f8b0:4864:20::b2b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F50487094 for ; Wed, 21 Sep 2022 01:12:32 -0700 (PDT) Received: by mail-yb1-xb2b.google.com with SMTP id b136so6954800yba.2 for ; Wed, 21 Sep 2022 01:12:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:mime-version:from:to:cc:subject :date; bh=yMP6fIsH3iK8GvA/5hVJOpgVRfJnpqAP6lVmWiyWygE=; b=OtLKSLekEe83VW0HHA+Z1P+31edmiC7w5LgdH0kmBcXqAWTy3V8oqXw4WJagZYElrM 6WmztvrZ+tfHWX88pLIfnPdvWRSNwjnsjOkFhxo2xpbCGrvkRH+LAs+Mtslrba0q+ME9 pDaDqZ4P9UCS6H5xEfj722VCW2I+L7seXw0hdNNhuUc49fuyk56XQWgsL7muNgvlBnta 2s1EO7O3bWYNfnlAn2YPK/RBIbKiFBOXpYAIs3MbF8js9gFwrAuGQb5o1LSzm8ndArj1 tRwHQ0jZG/3iuRF1L4D2RGZmFUVABTPd8AnupiB1ApGd8J9edb8HNaXizNUBd0iQRtC1 Hc7w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:mime-version:x-gm-message-state :from:to:cc:subject:date; bh=yMP6fIsH3iK8GvA/5hVJOpgVRfJnpqAP6lVmWiyWygE=; b=OeWukZD1lbiIqFDIBUM1kPhPHkXYnpJhjlooXBgSMUnZ8XizFdzkmLq8FEP/FQ2A1X KIQEINFAeDfOjPUcY8NdFTgi+tCnGBL/i3ht5VA3Gve3LzdahGzivW36i60S+aPxjcNm BFFxwEk06Ttc30cbv+wdo/l09zE6p6dLOPKDH6umj+538mTwUGCwLqf8jjiIHGsxwYgH J8llGtrpP8+xKwv19D4RAa64UP85BzD666zPpzIqEQsn0Fpe1W134a7KpDBs0vVXqA3I hppXl2QJxJoldrqEXOw1et1gUQ9TJMk7KS1TLtyh/ZWydA+9lHjsifCVR++JZDLGy5ns dSsw== X-Gm-Message-State: ACrzQf3y85RGlo7EXA2fVe6+z2nx2u2VuhrROk40WwZChUVjiGtzsCbg rhqNV5GZ1bLz5/p7fFEYZsnvAxO5vZfBNyAMQg4= X-Google-Smtp-Source: AMsMyM5M5QQFOZ8QlVYQq4CF+D1hmgstZ1hbisOqxlm830qNaqa7SxTt2euTjkxDvlrSnJqjyAFS7LNxX7Bk7Xa9/ys= X-Received: by 2002:a25:8152:0:b0:68b:1162:4312 with SMTP id j18-20020a258152000000b0068b11624312mr22896378ybm.289.1663747951428; Wed, 21 Sep 2022 01:12:31 -0700 (PDT) MIME-Version: 1.0 From: JaeJoon Jung Date: Wed, 21 Sep 2022 17:12:20 +0900 Message-ID: Subject: [core-scheduling] Modify prio_less() with in CONFIG_SCHED_CORE on v5.19.x To: Peter Zijlstra , Chris Hyser , Don Hiatt , Hongyu Ning , Vincent Guittot , Cruz Zhao Cc: linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Hello, Since the priority of sched_class can be determined by pointer operation, the prio_less() function can be modified as follows. With this fix, the __task_prio() function is not needed. Please review. diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ee28253c9ac0..24b86773da04 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -154,21 +154,6 @@ __read_mostly int scheduler_running; DEFINE_STATIC_KEY_FALSE(__sched_core_enabled); -/* kernel prio, less is more */ -static inline int __task_prio(struct task_struct *p) -{ - if (p->sched_class =3D=3D &stop_sched_class) /* trumps deadline */ - return -2; - - if (rt_prio(p->prio)) /* includes deadline */ - return p->prio; /* [-1, 99] */ - - if (p->sched_class =3D=3D &idle_sched_class) - return MAX_RT_PRIO + NICE_WIDTH; /* 140 */ - - return MAX_RT_PRIO + MAX_NICE; /* 120, squash fair */ -} - /* * l(a,b) * le(a,b) :=3D !l(b,a) @@ -179,22 +164,18 @@ static inline int __task_prio(struct task_struct *p) /* real prio, less is less */ static inline bool prio_less(struct task_struct *a, struct task_struct *b, bool in_fi) { - - int pa =3D __task_prio(a), pb =3D __task_prio(b); - - if (-pa < -pb) - return true; - - if (-pb < -pa) - return false; - - if (pa =3D=3D -1) /* dl_prio() doesn't work because of stop_class a= bove */ - return !dl_time_before(a->dl.deadline, b->dl.deadline); - - if (pa =3D=3D MAX_RT_PRIO + MAX_NICE) /* fair */ - return cfs_prio_less(a, b, in_fi); - - return false; + int less =3D a->sched_class - b->sched_class; + + if (less) { + return (less > 0) ? true : false; + } else { + if (a->sched_class =3D=3D &fair_sched_class) + return cfs_prio_less(a, b, in_fi); + else if (a->sched_class =3D=3D &dl_sched_class) + return !dl_time_before(a->dl.deadline, b->dl.deadli= ne); + else + return (a->prio - b->prio > 0) ? true : false; + } } Thanks, JaeJoon Jung.