From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f176.google.com (mail-pl1-f176.google.com [209.85.214.176]) (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 B7B61274652 for ; Fri, 24 Oct 2025 06:58:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761289133; cv=none; b=py42Hjl2/+3OOsS/SwqAIsK/ccdHK16HDiPiJuKV5VDokUHk9gOTp04oMSonr+NoJ8wSni8nZoCpxfLMYRIkctSlrw84umX/08HCt9fRb2N3lMWgZjEpiIvsuYYgTJvy4eRcT0G0gI1/AH8BfetfQuSFn1GXzdcP9xCn7qFBLPg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761289133; c=relaxed/simple; bh=ouuvPGm0sNumIUj8yL/i23jRDtD4FUp08+5H5fz4Wbg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=oe2Z83U/H3lUFTpgLwrYv7ObbpgAXXGdfJTluWQsxXs6T94Q9g+rBnCtk5i/eRBHoAPnnO43YJAXeYPOXfqRRnF9bS7A2onMVVDMA7ony6QQUP3lWEihKGa/Z/moT/2//at1lgDJdjomyAg0pGMtl71Si9HkJ6+idJO39mhxogM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=SHh21Toz; arc=none smtp.client-ip=209.85.214.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="SHh21Toz" Received: by mail-pl1-f176.google.com with SMTP id d9443c01a7336-290dc630a07so12235465ad.1 for ; Thu, 23 Oct 2025 23:58:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1761289131; x=1761893931; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:from:to:cc:subject:date :message-id:reply-to; bh=k87hOdMqC5Cdt3rAJ8+LiDSDQZa5GhKDKbVYp0AjmqY=; b=SHh21Toz5tVvp8ANRqRAs+DiwvdEDuPaupwuQWmeChPiRm2884qVsbJk8QLjJdOsEJ 2NDsvWovnEQubCm04feJuef+jT4QGe+M7KdTAARePGrd3BThQVQxKYHPFUBLRlMzRBhA BtncmgLcqvjUyYJ1VjX26qDk8/2RrM786zxp3ptm+dwk6KL1+UANW9vH1vHgfc1XZ2km 0XkTH5ZQL634WWSHWB+kGXu1fsx9JFBedJVWPYU/fcaUts1TmMz5zz+OctnWnYgBoMb7 zq5Zm/EB1zuk5xJRdBHrGri2Co0YKAv0JLSc63ENe/ffiOzvuysuocv4+xjwlwBGVIbk YpeA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761289131; x=1761893931; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=k87hOdMqC5Cdt3rAJ8+LiDSDQZa5GhKDKbVYp0AjmqY=; b=X4YffJkXcBTufy6DUzI/oLYlwX/cKacojKtFzAMpl5QhviKlT/bpafHbT9BuNiz8qP LI2aUm1LZZ+LISew1MOLl4KWce1LAIvWtq8DN+mHl17wqwLq9FfCaY2UWuCa0WOoq4Lm 4AsEEtve2o+G6nhSs8gfe8GY/A75B8JdpD7lks+XkmJFvBIYmvynH787uJfkOzNqpLa+ egtviqCihHEcn7/fz6PIGDSQOYpTsMPbE+Lg0m1kq/C0xiDIa3Olm7MLA5QD6IILbBQ5 aY7P+ivr8x/ckSNRCrniz6dZEKAqgpGAfLfQSRnD0KTII/Fp7A3VIDHhqfmzt1dhxLa1 ctgQ== X-Gm-Message-State: AOJu0YwvQ5z54Gp57gwq7DA4MyKFHi4q91n/Q3JdDhhrgn0pP65jullB j9Wf0CdQTmEyOU+vr9sAV8iVr13dkUXTpWkLmRpoCBVrV9aPEYCMdCPl X-Gm-Gg: ASbGncs1OrzBnB8LpIHJ6sMZsjAtLb1E7N/VAI/ZahzpiWzGA58gf80/sZFW527i6xu NfQ6FjU980Pv5gvh7d1i+Bdbkya1bZn5zTJ19Hzg9ZpPBP/L3FHGUMR9nF0YeERd/r9fB5VkMnk OhE4vgQp/yuaX/Hd4IruQjPxswtb6i/lXvaiPp+SYlfZkxiD+j+vAi15iGlrfsCCaFGmAsiAK0h qDYP6LrNAVRIi80hjrY06rxORRWlvSFB3KTvhGS/NNsS5QZ11UVfTiM/Tk5GiDqjfP3VBIv3owa XaTiiB5HAWff08gBK7+2oEALmQRzxAmTJd+YmorXMHbHesSUd59Gj2smzXkq2XoF8sSrRSWGBv3 V51bDjcGCRUzL/xDAHjBhu0TuecHkAhRdC+c8FElwhRbgmoODaG4FT87pOYP3Mu35ODKPrvYMr8 RPYBYBJ7nR9PXtSJOCVLQ2rYnQxR7RrB8= X-Google-Smtp-Source: AGHT+IEgJgSJT4c559o77/ns1JxQ3O0Fpw3oD26TngmT8w9TA3KEe2VfcEYAUCHIIs/Ae1dHnnUPag== X-Received: by 2002:a17:902:db11:b0:240:48f4:40f7 with SMTP id d9443c01a7336-290cba4efc9mr416493535ad.39.1761289130959; Thu, 23 Oct 2025 23:58:50 -0700 (PDT) Received: from [10.125.192.78] ([210.184.73.204]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-33e2247a342sm8113140a91.13.2025.10.23.23.58.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 23 Oct 2025 23:58:50 -0700 (PDT) Message-ID: <561a15f5-3391-2796-6454-b980e0a228bd@gmail.com> Date: Fri, 24 Oct 2025 14:58:41 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.15.0 Subject: Re: [PATCH] sched/fair: Fix non-empty throttled_limbo_list warning in tg_throttle_down() To: K Prateek Nayak , mingo@redhat.com, peterz@infradead.org, mingo@kernel.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com Cc: linux-kernel@vger.kernel.org, Hao Jia , Aaron Lu References: <20251023121213.38282-1-jiahao.kernel@gmail.com> <98c1968e-8629-43d1-a4b8-600d263bd5a1@amd.com> From: Hao Jia In-Reply-To: <98c1968e-8629-43d1-a4b8-600d263bd5a1@amd.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi Prateek, On 2025/10/24 12:36, K Prateek Nayak wrote: > Hello Hao, > > On 10/23/2025 5:42 PM, Hao Jia wrote: >> @@ -5287,7 +5287,9 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) >> se->on_rq = 1; >> >> if (cfs_rq->nr_queued == 1) { >> - check_enqueue_throttle(cfs_rq); >> + if (!(flags & ENQUEUE_THROTTLE)) >> + check_enqueue_throttle(cfs_rq); >> + > > So my only concern here is: > > check_enqueue_throttle() > account_cfs_rq_runtime() > __account_cfs_rq_runtime() > assign_cfs_rq_runtime() > __assign_cfs_rq_runtime() > start_cfs_bandwidth() /* Starts the BW timer. */ > > If we skip it, we wouldn't know we've run out of bandwidth until the > hierarchy is picked which would cause additional delay until the > bandwidth is replenished. > > At the very least, we should pass the enqueue flags to > check_enqueue_throttle() and only skip the throttle_cfs_rq() part if > we spot ENQUEUE_THROTTLE. > > Thoughts? > Thanks for your suggestion. This is indeed a potential risk, and it will do it in the next version. Thanks, Hao