From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2E685C55178 for ; Thu, 29 Oct 2020 10:52:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB16220731 for ; Thu, 29 Oct 2020 10:52:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="gRM8gDdN"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="nLLrolaK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727269AbgJ2KwR (ORCPT ); Thu, 29 Oct 2020 06:52:17 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:60882 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727099AbgJ2Kvx (ORCPT ); Thu, 29 Oct 2020 06:51:53 -0400 Date: Thu, 29 Oct 2020 10:51:49 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1603968710; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WzksZVrMK2zPTuyPLMMf1+tEGIwWOTpopvEIMOtozA8=; b=gRM8gDdN7wcD6eiTNs5ry/ViYe+9sCRWLDSnXo0KNPFFdLONbCkNo1e5mzqCM+/dVNLuWi qPMleeCtkMpPkybwrmjSGol6NnFmLlZmNJQh1fkiuXAoefmATfL0r1VM11ptZTWI5KMFBT KwDu2/SQucK8PdX/zRkkuGd6OZ6ji7rjQ45vY7IkdiyA7OZCDk0nu4Py7isb8cqzDmFDJZ PgR6NJ5HKgjTQaZfeVFtG3ifHxUzLeCVG3aw6jCZOqI5t57nvyBFEy16z3MRQMmPH3RDt2 o4r/dkkYmW+cJyycm4uTKf+qebR5JgtMFjj0/MAnfBlbggOY1SQUj8ulHwjltA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1603968710; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WzksZVrMK2zPTuyPLMMf1+tEGIwWOTpopvEIMOtozA8=; b=nLLrolaKpbKJ70ie+YRK2xBXe5vF3ADHj5r/gI6zWyfpWQCO9M+yqTW0Xl68KrT1XLESHU hIka821alynBPCBA== From: "tip-bot2 for Dietmar Eggemann" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched/cpupri: Remove pri_to_cpu[1] Cc: Dietmar Eggemann , "Peter Zijlstra (Intel)" , x86 , LKML In-Reply-To: <20200922083934.19275-3-dietmar.eggemann@arm.com> References: <20200922083934.19275-3-dietmar.eggemann@arm.com> MIME-Version: 1.0 Message-ID: <160396870990.397.13763662113721048647.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the sched/core branch of tip: Commit-ID: 1b08782ce31f612d98e11ccccf3e3df9a147a67d Gitweb: https://git.kernel.org/tip/1b08782ce31f612d98e11ccccf3e3df9a147a67d Author: Dietmar Eggemann AuthorDate: Tue, 22 Sep 2020 10:39:34 +02:00 Committer: Peter Zijlstra CommitterDate: Thu, 29 Oct 2020 11:00:29 +01:00 sched/cpupri: Remove pri_to_cpu[1] pri_to_cpu[1] isn't used since cpupri_set(..., newpri) is never called with newpri = 99. The valid RT priorities RT1..RT99 (p->rt_priority = [1..99]) map into cpupri (idx of pri_to_cpu[]) = [2..100] Current mapping: p->rt_priority p->prio newpri cpupri -1 -1 (CPUPRI_INVALID) 100 0 (CPUPRI_NORMAL) 1 98 98 2 ... 49 50 50 50 50 49 49 51 ... 99 0 0 100 So cpupri = 1 isn't used. Reduce the size of pri_to_cpu[] by 1 and adapt the cpupri implementation accordingly. This will save a useless for loop with an atomic_read in cpupri_find_fitness() calling __cpupri_find(). New mapping: p->rt_priority p->prio newpri cpupri -1 -1 (CPUPRI_INVALID) 100 0 (CPUPRI_NORMAL) 1 98 98 1 ... 49 50 50 49 50 49 49 50 ... 99 0 0 99 Signed-off-by: Dietmar Eggemann Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200922083934.19275-3-dietmar.eggemann@arm.com --- kernel/sched/cpupri.c | 6 +++--- kernel/sched/cpupri.h | 4 ++-- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/kernel/sched/cpupri.c b/kernel/sched/cpupri.c index a5d14ed..8d9952a 100644 --- a/kernel/sched/cpupri.c +++ b/kernel/sched/cpupri.c @@ -19,12 +19,12 @@ * in that class). Therefore a typical application without affinity * restrictions can find a suitable CPU with O(1) complexity (e.g. two bit * searches). For tasks with affinity restrictions, the algorithm has a - * worst case complexity of O(min(101, nr_domcpus)), though the scenario that + * worst case complexity of O(min(100, nr_domcpus)), though the scenario that * yields the worst case search is fairly contrived. */ #include "sched.h" -/* Convert between a 140 based task->prio, and our 101 based cpupri */ +/* Convert between a 140 based task->prio, and our 100 based cpupri */ static int convert_prio(int prio) { int cpupri; @@ -34,7 +34,7 @@ static int convert_prio(int prio) else if (prio >= MAX_RT_PRIO) cpupri = CPUPRI_NORMAL; else - cpupri = MAX_RT_PRIO - prio; + cpupri = MAX_RT_PRIO - prio - 1; return cpupri; } diff --git a/kernel/sched/cpupri.h b/kernel/sched/cpupri.h index 1a16236..e28e1ed 100644 --- a/kernel/sched/cpupri.h +++ b/kernel/sched/cpupri.h @@ -1,10 +1,10 @@ /* SPDX-License-Identifier: GPL-2.0 */ -#define CPUPRI_NR_PRIORITIES (MAX_RT_PRIO + 1) +#define CPUPRI_NR_PRIORITIES MAX_RT_PRIO #define CPUPRI_INVALID -1 #define CPUPRI_NORMAL 0 -/* values 2-100 are RT priorities 0-99 */ +/* values 1-99 are for RT1-RT99 priorities */ struct cpupri_vec { atomic_t count;