From nobody Tue Apr 7 17:48:09 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 60DD7C433FE for ; Tue, 18 Oct 2022 12:42:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230125AbiJRMm6 (ORCPT ); Tue, 18 Oct 2022 08:42:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230109AbiJRMmz (ORCPT ); Tue, 18 Oct 2022 08:42:55 -0400 Received: from mail-ed1-x531.google.com (mail-ed1-x531.google.com [IPv6:2a00:1450:4864:20::531]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 36A3FC1D9F for ; Tue, 18 Oct 2022 05:42:53 -0700 (PDT) Received: by mail-ed1-x531.google.com with SMTP id z97so20241983ede.8 for ; Tue, 18 Oct 2022 05:42:53 -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:message-id:reply-to; bh=yMP6fIsH3iK8GvA/5hVJOpgVRfJnpqAP6lVmWiyWygE=; b=f+yELfdZ47XzJ+BJzeb7htVmv1joFeJ0NqAak3zL6TROI4B11piQZ2iVrsJcg+5F31 gAXNnWkUOREl4sLTvoKD18xGUjkyuYK0LuWBnA8g17PMusFAqNYjbqhQFW15fGAh382g dp8ZCnrIOq6F6W47+MkAOhaAJm3WNgTX5kPolUG3mcOiEuVxB8FD6toXYuhPhGpXf60f Z8uoxnRDs8Nx69yZkmqiitDM4W6hGAu/QxBVmJI2FdjwAeifjFhZP384qxt9RdMp3voA 95sLDELZHhIihTc1Oz8Z02WUrjzGr3J13dbyNWxijVCFX//MVHs2PxeIN5eQkQehdb0K PFfw== 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:message-id:reply-to; bh=yMP6fIsH3iK8GvA/5hVJOpgVRfJnpqAP6lVmWiyWygE=; b=uH0X+WikEmLcSFvMReimhhX45V+SNXE2QIo15EA4OuqVFgs3tnfmIC26uvnn6Xkxm3 5nBEmRBbdzhAl2khDiqG05xv2PBDjs0V83BeH4Bi2krBH5LYEbTtSOxURrZBqzO4XjU3 8EJm+EXZ9iyh8e0pgDxB4QaGWEk19HRKzFL+HTG1MixqUmhyaA0QK+mZh3JtmaVsulSE 8wNXq8OIDq8IANS/TCpr4CG1qylPA65NpKHvlI56BY/BYyexpb4ZCWQYhyYEtht+axPn EJGesvkbEQf0nAtXEsgiaaBas0gs+EZOizr2QKyACrBcdFYY8v+oXgZTGOTe9yv46r/4 iWhw== X-Gm-Message-State: ACrzQf2pV2Ick31AgOAwgrHqw4rk7FNx7GSFDgSacmcPX+h9XyvIdqD1 0MUPKviOMhdH7EdROi13PsGlWnYswF5JBRnsobopgEEgXAg= X-Google-Smtp-Source: AMsMyM5mAjPZvG/k4IHFmA9D7OeQo3AejAZ5I9SIzubNLQsvefoJ2et+wacsozv8bDL9L/QS7q5q7YfBOAy70BbaqoQ= X-Received: by 2002:a05:6402:27d4:b0:45d:a69e:336d with SMTP id c20-20020a05640227d400b0045da69e336dmr2416594ede.298.1666096971346; Tue, 18 Oct 2022 05:42:51 -0700 (PDT) MIME-Version: 1.0 From: JaeJoon Jung Date: Tue, 18 Oct 2022 21:42:39 +0900 Message-ID: Subject: [core-scheduling] Modify prio_less() with in CONFIG_SCHED_CORE 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.