From nobody Mon Feb 9 00:42:27 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6FA447E119; Tue, 12 Mar 2024 12:00:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710244838; cv=none; b=MFX94Ol0dy9iXPBcoq4/Gj5Db+14rCoDquQitSExk28KePr6Zw7SivXo65VnlEJ3ex7gku5t4sAcdNODlCMSZdThptQtGizsksSGPTnHoQQZYitUlwcHPSbufYVokUC2HQc7k4ZDLvZJSk3gUfX3TEgOzoXSFuLrovmyImcOCqI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710244838; c=relaxed/simple; bh=yyYeHYZBueKP144TnOAZc2ZB9b7S1A8d+6M7LwHsntU=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=CKTEcZXqfDa6eaROfHtjWUWp3ZMjH2DP1p00t+GDtTA3mwfpjMMLJRwPUvLCL7d9N153HN6rqm9FFqtiA8v49j5gZhIcZZgAm74lnU/JdUVv9QIwwRs/JWUDuENGsmBVic+KHYaVVcpRex14cL7NVjvSOXHsaYvgkQghiwLDxpg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Z22UkzfA; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Xa77iOTw; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Z22UkzfA"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Xa77iOTw" Date: Tue, 12 Mar 2024 12:00:34 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1710244834; 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=zGsnJkxiuDTrLJSj9ooSp1Zwaa9UFKn+9GLbz2Er8Ek=; b=Z22UkzfApMUfpc5mwv4MDhuj5ul/eIpnJPDV5O8AccR1lGrkRkpiTwzLH3yqTf1hG/zinY Zre7rzjemSs8CLqt4zI5EwsQaz3ZoLHDwpquO7tOaB46ig1/N6sN4QrHV+AOkh6RH9zCzV BPSL4vsebNkkmERHCTggqPZGw03xvRAvAMBBBBaOfsGN6gihumAM7L+RqWVn+2JRXAueXI 65uMS93EF2fi33raWCmp4SrH2fSMTUPrUZqSgUMHRJE1/ffe6/psSYAF2UCO+HlODd6uMK mFqIJwXd3qSfXsrhEXg/Vj2OVmhHQTNytDzcoLxpHsdEX7USv0SBDdvYZwUk7Q== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1710244834; 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=zGsnJkxiuDTrLJSj9ooSp1Zwaa9UFKn+9GLbz2Er8Ek=; b=Xa77iOTw2XWOxomeC/etefPFLHdsum0Wc6IrlGBHhK7dxRR6sqRlMz/Bw/taDDphT7VmQZ 9sP1Oyymp9nCYpAg== From: "tip-bot2 for Ingo Molnar" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched/balancing: Change 'enum cpu_idle_type' to have more natural definitions Cc: Ingo Molnar , Valentin Schneider , Vincent Guittot , "Gautham R. Shenoy" , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20240308105901.1096078-4-mingo@kernel.org> References: <20240308105901.1096078-4-mingo@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <171024483402.398.15168980495153981545.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the sched/core branch of tip: Commit-ID: 38d707c54df4ca58cd9ceae2ddcbd6f606b99e9f Gitweb: https://git.kernel.org/tip/38d707c54df4ca58cd9ceae2ddcbd6f60= 6b99e9f Author: Ingo Molnar AuthorDate: Fri, 08 Mar 2024 11:58:54 +01:00 Committer: Ingo Molnar CommitterDate: Tue, 12 Mar 2024 11:03:40 +01:00 sched/balancing: Change 'enum cpu_idle_type' to have more natural definitio= ns The cpu_idle_type enum has the confusingly inverted property that 'not idle' is 1, and 'idle' is '0'. This resulted in a number of unnecessary complications in the code. Reverse the order, remove the CPU_NOT_IDLE type, and convert all code to a natural boolean form. It's much more readable: - enum cpu_idle_type idle =3D this_rq->idle_balance ? - CPU_IDLE : CPU_NOT_IDLE; - + enum cpu_idle_type idle =3D this_rq->idle_balance; -------------------------------- - if (env->idle =3D=3D CPU_NOT_IDLE || !busiest->sum_nr_running) + if (!env->idle || !busiest->sum_nr_running) -------------------------------- And gets rid of the double negation in these usages: - if (env->idle !=3D CPU_NOT_IDLE && env->src_rq->nr_runnin= g <=3D 1) + if (env->idle && env->src_rq->nr_running <=3D 1) Furthermore, this makes code much more obvious where there's differentiation between CPU_IDLE and CPU_NEWLY_IDLE. Signed-off-by: Ingo Molnar Reviewed-by: Valentin Schneider Reviewed-by: Vincent Guittot Cc: "Gautham R. Shenoy" Link: https://lore.kernel.org/r/20240308105901.1096078-4-mingo@kernel.org --- include/linux/sched/idle.h | 2 +- kernel/sched/fair.c | 27 ++++++++++++--------------- 2 files changed, 13 insertions(+), 16 deletions(-) diff --git a/include/linux/sched/idle.h b/include/linux/sched/idle.h index 478084f..e670ac2 100644 --- a/include/linux/sched/idle.h +++ b/include/linux/sched/idle.h @@ -5,8 +5,8 @@ #include =20 enum cpu_idle_type { + __CPU_NOT_IDLE =3D 0, CPU_IDLE, - CPU_NOT_IDLE, CPU_NEWLY_IDLE, CPU_MAX_IDLE_TYPES }; diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 2ef89b3..3a510cf 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -9070,7 +9070,7 @@ static int detach_tasks(struct lb_env *env) * We don't want to steal all, otherwise we may be treated likewise, * which could at worst lead to a livelock crash. */ - if (env->idle !=3D CPU_NOT_IDLE && env->src_rq->nr_running <=3D 1) + if (env->idle && env->src_rq->nr_running <=3D 1) break; =20 env->loop++; @@ -9803,7 +9803,7 @@ static inline bool smt_vs_nonsmt_groups(struct sched_= group *sg1, static inline bool smt_balance(struct lb_env *env, struct sg_lb_stats *sgs, struct sched_group *group) { - if (env->idle =3D=3D CPU_NOT_IDLE) + if (!env->idle) return false; =20 /* @@ -9827,7 +9827,7 @@ static inline long sibling_imbalance(struct lb_env *e= nv, int ncores_busiest, ncores_local; long imbalance; =20 - if (env->idle =3D=3D CPU_NOT_IDLE || !busiest->sum_nr_running) + if (!env->idle || !busiest->sum_nr_running) return 0; =20 ncores_busiest =3D sds->busiest->cores; @@ -9927,8 +9927,7 @@ static inline void update_sg_lb_stats(struct lb_env *= env, sgs->group_misfit_task_load =3D rq->misfit_task_load; *sg_status |=3D SG_OVERLOAD; } - } else if ((env->idle !=3D CPU_NOT_IDLE) && - sched_reduced_capacity(rq, env->sd)) { + } else if (env->idle && sched_reduced_capacity(rq, env->sd)) { /* Check for a task running on a CPU with reduced capacity */ if (sgs->group_misfit_task_load < load) sgs->group_misfit_task_load =3D load; @@ -9940,7 +9939,7 @@ static inline void update_sg_lb_stats(struct lb_env *= env, sgs->group_weight =3D group->group_weight; =20 /* Check if dst CPU is idle and preferred to this group */ - if (!local_group && env->idle !=3D CPU_NOT_IDLE && sgs->sum_h_nr_running = && + if (!local_group && env->idle && sgs->sum_h_nr_running && sched_group_asym(env, sgs, group)) sgs->group_asym_packing =3D 1; =20 @@ -10698,7 +10697,7 @@ static inline void calculate_imbalance(struct lb_en= v *env, struct sd_lb_stats *s * waiting task in this overloaded busiest group. Let's * try to pull it. */ - if (env->idle !=3D CPU_NOT_IDLE && env->imbalance =3D=3D 0) { + if (env->idle && env->imbalance =3D=3D 0) { env->migration_type =3D migrate_task; env->imbalance =3D 1; } @@ -10913,7 +10912,7 @@ static struct sched_group *find_busiest_group(struc= t lb_env *env) goto force_balance; =20 if (busiest->group_type !=3D group_overloaded) { - if (env->idle =3D=3D CPU_NOT_IDLE) { + if (!env->idle) { /* * If the busiest group is not overloaded (and as a * result the local one too) but this CPU is already @@ -11121,7 +11120,7 @@ asym_active_balance(struct lb_env *env) * the lower priority @env::dst_cpu help it. Do not follow * CPU priority. */ - return env->idle !=3D CPU_NOT_IDLE && sched_use_asym_prio(env->sd, env->d= st_cpu) && + return env->idle && sched_use_asym_prio(env->sd, env->dst_cpu) && (sched_asym_prefer(env->dst_cpu, env->src_cpu) || !sched_use_asym_prio(env->sd, env->src_cpu)); } @@ -11159,7 +11158,7 @@ static int need_active_balance(struct lb_env *env) * because of other sched_class or IRQs if more capacity stays * available on dst_cpu. */ - if ((env->idle !=3D CPU_NOT_IDLE) && + if (env->idle && (env->src_rq->cfs.h_nr_running =3D=3D 1)) { if ((check_cpu_capacity(env->src_rq, sd)) && (capacity_of(env->src_cpu)*sd->imbalance_pct < capacity_of(env->dst_= cpu)*100)) @@ -11735,8 +11734,8 @@ static void rebalance_domains(struct rq *rq, enum c= pu_idle_type idle) * env->dst_cpu, so we can't know our idle * state even if we migrated tasks. Update it. */ - idle =3D idle_cpu(cpu) ? CPU_IDLE : CPU_NOT_IDLE; - busy =3D idle !=3D CPU_IDLE && !sched_idle_cpu(cpu); + idle =3D idle_cpu(cpu); + busy =3D !idle && !sched_idle_cpu(cpu); } sd->last_balance =3D jiffies; interval =3D get_sd_balance_interval(sd, busy); @@ -12416,9 +12415,7 @@ out: static __latent_entropy void run_rebalance_domains(struct softirq_action *= h) { struct rq *this_rq =3D this_rq(); - enum cpu_idle_type idle =3D this_rq->idle_balance ? - CPU_IDLE : CPU_NOT_IDLE; - + enum cpu_idle_type idle =3D this_rq->idle_balance; /* * If this CPU has a pending nohz_balance_kick, then do the * balancing on behalf of the other idle CPUs whose ticks are