From nobody Mon Feb 9 06:28:55 2026 Received: from mail-qk1-f201.google.com (mail-qk1-f201.google.com [209.85.222.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B5F31213240 for ; Wed, 4 Jun 2025 19:59:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749067155; cv=none; b=qAt7OpiXUTlcvppnv/gf5+yQ2ntNvd0+M2hPIwNkg3AEmBWYT8l7s7HnMgvTSGZmbJO7yJ9E2C2jwn3QT5AjKFfhcMTVbkF9xVte0gJtLFXiHeL28aZDm5VMU3LLMTY0hmZRijCBhTTrxIbJGDs714fnGWTqCsRSIMZSaLq9Qjc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749067155; c=relaxed/simple; bh=hNsugqu2cMOw3pa8As49Fq/LBELbjZEHbAsiXWjpb0Y=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=MmrhhMdj4VRtVLOXVXH/+gzZscSmKZ41Mbeh+Alg08+0qkGV07/7jGrbhG0Yp+GUcGYMtU7Zzp1T8LIBYuQcNT08CFn54n8iCYWw/pykqPOxDM2/X1c9PhL6I9xEePqb55mIlXaEkiMHULfrjnIpIAsRP+MNnq6ixBDuj0W3TRU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--zecheng.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=s3gl0WMx; arc=none smtp.client-ip=209.85.222.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--zecheng.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="s3gl0WMx" Received: by mail-qk1-f201.google.com with SMTP id af79cd13be357-7c5cd0f8961so45034285a.1 for ; Wed, 04 Jun 2025 12:59:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1749067152; x=1749671952; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=BE1JvPau67Augvd0EXHJU7jahlXkBqnSAfRcstGC/1o=; b=s3gl0WMxCWAEhejB5+3aHxDuIdD3auK2C7bKpw6uvf7XIey0E6UNUo67IaqEOLeP46 ZYdil9Ghwpdz2iVR4Bd0kyitD2rUNNfW2ZnV/+T3fMqSx34XCbXksfVXjSUkodIKC6Mz /uu/NvMz+fP8wow3HlW3U7KLaElpl7Wyj3vwAyoZ9gJRhWdHea744j9c9qGzymf8cJlf hn59ySwsMcGcw+eI2L1bpY/eHCzABiNAMwJQlJLSA/0sfqZ7e36yjZbw/xAsHVsD4cEW 1DDrxrIMxRDSNHCP8Z6dYo+lu0dp5UtRgRmxWSAo0UTRfUgYB1TFpHsxY+OXRfNp3kWZ hm1Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1749067152; x=1749671952; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=BE1JvPau67Augvd0EXHJU7jahlXkBqnSAfRcstGC/1o=; b=O1Js8nDWz7g8LxrMkMGKZaJJj2VHLfd1FI+eJrVLD++1BE770NRn+r2yDrUxU23sY/ q5JiCF5QMjyOYs0CrBCyVf6BnZFEslF0HyzZrfqVtp2+/MSrJVip/Je0DecAGUrUyH/I XTet+rIX2T6AZgc0kQHStqTAMu5ZkS5WS+EkV0Vd6OE0xAWAoAPIoz6cnj2IafvLu1Ks k7zY/05H5bmGhRvDcLojp31NopIWoyy9g9bN2Yhua5yQYiaZm3VRTUVu393kpuUBlRAu c8CF9XnPnqTm22LxTzg21KnBCVQKwvhYaxAV8q0VI0pVWjweOh2bGDI7i+vEEFh9xGK5 Aiqw== X-Forwarded-Encrypted: i=1; AJvYcCVB0l2pHENdz7c2hHDJkIXDtvgVxMDJKv5mHO9O+on4YWkDSynscsNF28j/Mj9MaMs6THDSs1tRJ5PcSAM=@vger.kernel.org X-Gm-Message-State: AOJu0YxefFUIuLyp7tt+YaUkNUP0m70RKVG0PElSPrrvy+nLQfvAiqNw UtVaVUdpTgnchzRw5Df2N5CcVwQiAWZD6m4741pIp7aD70aQqAmh36rGpo5LEuQtRm+MM8Z3KZ9 tTuSXFl+pgw== X-Google-Smtp-Source: AGHT+IH2PVPU+jnCDOWlvH1nmTCsP6zZPCzuBIXNirLucuXHv9eITdBYMuX/KC8xAAlbaVmrnjaKIXmwEmUt X-Received: from qkzz15.prod.google.com ([2002:a05:620a:8cf:b0:7ce:d551:8079]) (user=zecheng job=prod-delivery.src-stubby-dispatcher) by 2002:a05:620a:45a7:b0:7d2:1509:752e with SMTP id af79cd13be357-7d21991bef7mr636055485a.58.1749067152578; Wed, 04 Jun 2025 12:59:12 -0700 (PDT) Date: Wed, 4 Jun 2025 19:58:41 +0000 In-Reply-To: <20250604195846.193159-1-zecheng@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250604195846.193159-1-zecheng@google.com> X-Mailer: git-send-email 2.50.0.rc0.642.g800a2b2222-goog Message-ID: <20250604195846.193159-2-zecheng@google.com> Subject: [RFC PATCH 1/3] sched/fair: Embed sched_entity into cfs_rq From: Zecheng Li To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot Cc: Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Xu Liu , Blake Jones , Josh Don , linux-kernel@vger.kernel.org, Zecheng Li Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" To improve data locality and avoid pointer chasing, embed struct sched_entity within struct cfs_rq. This co-locates the runqueue state (cfs_rq) and the entity's scheduling state (se). This patch implements the following: - Adds a struct sched_entity field to struct cfs_rq. - Modifies alloc_fair_sched_group() and free_fair_sched_group() to remove the separate allocation and freeing logic for sched_entity objects themselves. - The task_group->se pointer array (struct sched_entity **se) is retained. The pointers in this array are updated to point to the corresponding embedded &cfs_rq->se for each CPU. Signed-off-by: Zecheng Li --- kernel/sched/fair.c | 10 +--------- kernel/sched/sched.h | 4 ++++ 2 files changed, 5 insertions(+), 9 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 0fb9bf995a47..c2af9896eef4 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -13343,8 +13343,6 @@ void free_fair_sched_group(struct task_group *tg) for_each_possible_cpu(i) { if (tg->cfs_rq) kfree(tg->cfs_rq[i]); - if (tg->se) - kfree(tg->se[i]); } =20 kfree(tg->cfs_rq); @@ -13374,11 +13372,7 @@ int alloc_fair_sched_group(struct task_group *tg, = struct task_group *parent) if (!cfs_rq) goto err; =20 - se =3D kzalloc_node(sizeof(struct sched_entity_stats), - GFP_KERNEL, cpu_to_node(i)); - if (!se) - goto err_free_rq; - + se =3D &cfs_rq->se; init_cfs_rq(cfs_rq); init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]); init_entity_runnable_average(se); @@ -13386,8 +13380,6 @@ int alloc_fair_sched_group(struct task_group *tg, s= truct task_group *parent) =20 return 1; =20 -err_free_rq: - kfree(cfs_rq); err: return 0; } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 47972f34ea70..6e26b7d59c13 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -738,6 +738,10 @@ struct cfs_rq { struct list_head throttled_csd_list; #endif /* CONFIG_CFS_BANDWIDTH */ #endif /* CONFIG_FAIR_GROUP_SCHED */ +#ifdef CONFIG_FAIR_GROUP_SCHED + /* sched_entity on parent runqueue */ + struct sched_entity se ____cacheline_aligned; +#endif }; =20 #ifdef CONFIG_SCHED_CLASS_EXT --=20 2.50.0