From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.14]) (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 62CFA4078DC for ; Thu, 1 Oct 2026 21:55:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790891704; cv=none; b=fyH9nmwN6Shqc0lF0o9aFbv6yGz/8H0/Hb+3mnLJRvoQ2WgkGltk6pEsmnFpfPGeBMVPEIV0ojV+Wz5Be63wBhz+MDZMSjOJ9nW36ZwRIhRUy/f0AieIDkIll28GODEJI3BHBsBmhYPF5y4er4U4n2EkCgHnHbucTadbdtaprPo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790891704; c=relaxed/simple; bh=k227Sw7GESYXAbhF/BZM1Xe5SlltP8tDEyv8sVotVGw=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=np4NUUbfwN5SsAC43iOXiuOZ+hDTw8Y52uG2azJ45OsRJGT4MGr7kyh8TBFDT0QKptzE5+1HAs3iUfKREPNSogI4OVA04Yq4H64P099ITVvSTC/it3obfF7EbVCA2MXACtpnFQw8FWp4TlRv8DezXcbAUrA9yEjz96ve0svpNFM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=bYEaujDu; arc=none smtp.client-ip=192.198.163.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="bYEaujDu" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1790891703; x=1822427703; h=message-id:subject:from:to:cc:date:in-reply-to: references:content-transfer-encoding:mime-version; bh=k227Sw7GESYXAbhF/BZM1Xe5SlltP8tDEyv8sVotVGw=; b=bYEaujDu0hjU7qeH3cWSp7YAQUAGUtsn819KIb6wq9nZYPbq6Aj0w5mI 7R2h9ZOKA9BAv+S/b6bxAgA1mJRS8Cg7bKfGM14tUpeTD2yEJyxkQJNub qQFhaKrw7shKQ8xHiE4X03UWIYlnemZV4cwtuWQU3azhVPP5TGhNXV3Zi XWyTaWyFc9fj3UPgjblzmmTX7a5gK5eO/GGdp+qsSKMAU4LRUJGhZFRby 9Ekmkr0qNYEdUWaUJiLt3YtdGk3q33FxsLAy2SUN53dFZx/uOG+go72LL cX9g2bYdJhFEnXyPN+341UuV6hNxrP194rioRAgvQpr22U7CTCcXDyVGW A==; X-CSE-ConnectionGUID: 6b7NsSfmS/qypX7kaBf8Mg== X-CSE-MsgGUID: 5dOQOD8JSZOVPpDLofc3Vg== X-IronPort-AV: E=McAfee;i="6800,10657,11922"; a="91683213" X-IronPort-AV: E=Sophos;i="6.27,135,1787036400"; d="scan'208";a="91683213" Received: from fmviesa008.fm.intel.com ([10.60.135.148]) by fmvoesa108.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Oct 2026 14:55:02 -0700 X-CSE-ConnectionGUID: NXiTJDphS26CxbCke+ZFxg== X-CSE-MsgGUID: Dyo7jFDJQjCkBQ4rwVk9mg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,135,1787036400"; d="scan'208";a="276203756" Received: from schen9-mobl4.amr.corp.intel.com (HELO [10.125.108.6]) ([10.125.108.6]) by fmviesa008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Oct 2026 14:55:00 -0700 Message-ID: <88f28ac61e238cef9bcf8bda3adb4326c15ba15e.camel@linux.intel.com> Subject: Re: [PATCH 2/3] sched/fair: Rename group_imbalanced to group_pinned_task From: Tim Chen To: Jemmy Wong , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot Cc: Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , linux-kernel@vger.kernel.org Date: Thu, 01 Oct 2026 14:54:59 -0700 In-Reply-To: <20260928042018.10618-3-jemmywong512@gmail.com> References: <20260928042018.10618-1-jemmywong512@gmail.com> <20260928042018.10618-3-jemmywong512@gmail.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.1 (3.58.1-1.fc43) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Mon, 2026-09-28 at 12:20 +0800, Jemmy Wong wrote: > The name dates back to the original group_imb heuristic, which flagged > a group when the load difference between its busiest and idlest CPU > exceeded the average task load. Commit 6263322c5e8f ("sched/fair: > Rewrite group_imb trigger") replaced that heuristic: the flag is now > set only when a lower domain fails to balance because tasks are pinned > by cpus_ptr (LBF_SOME_PINNED), and kept while all tasks are pinned > (LBF_ALL_PINNED). The name was carried over unchanged and later became > group_imbalanced in commit 0b0695f2b34a ("sched/fair: Rework > load_balance()"). >=20 > Today the name no longer matches the condition: >=20 > - group_classify() checks group_overloaded first, so a group whose > load really is skewed is usually not classified as imbalanced, > while a flagged group may carry a single extra task. >=20 > - calculate_imbalance() does not measure any imbalance for this type; > it moves one task (migrate_task, imbalance =3D 1). >=20 > - Elsewhere in fair.c "imbalance" consistently means the amount of > load to move (env->imbalance, imbalance_pct, calculate_imbalance(), > the lb_imbalance_* schedstats), and imbalanced_active_balance() uses > "imbalanced" for repeated balance failures, unrelated to this flag. >=20 > Rename it to group_pinned_task, which describes the condition that > raises it and follows the adjective_noun pattern of group_misfit_task. > The enum is local to fair.c, so no tracepoint, schedstat or other > user-visible interface is affected. >=20 > No functional change. >=20 > Signed-off-by: Jemmy Wong > --- > kernel/sched/fair.c | 30 +++++++++++++++--------------- > 1 file changed, 15 insertions(+), 15 deletions(-) >=20 > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index f9ddcecfd19d..aa63950976aa 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -10363,7 +10363,7 @@ enum group_type { > * The tasks' affinity constraints previously prevented the scheduler > * from balancing the load across the system. > */ > - group_imbalanced, > + group_pinned_task, I believe we are trying to fix imbalance due to pinned tasks. Perhaps group_pinned_imbalance is more descriptive. Tim