From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-111.freemail.mail.aliyun.com (out30-111.freemail.mail.aliyun.com [115.124.30.111]) (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 87F79126C10 for ; Tue, 25 Feb 2025 06:56:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.111 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740466620; cv=none; b=YRTxC6WjeOkC6g4qMQNzqIhkQBkOE9FETiuP8TjYxq75681sYy83f/nMgfPpNaHt75k3XI3wgV8NI+PrixW1B0l14SuNvVPkLL55J492Lc9W63eIU4KuIsNmb9w2atOjnTuSdg0RN7ry+oIenLzIq7PA7OGZpTg5FEwDbBgsM38= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740466620; c=relaxed/simple; bh=e3+aNYTnbKWJivg+q+Hi3DtLQsrRb9Bk6wUzOAsG45k=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=iPnIIHVBMLXbvqZq5gdOUbjXNj3LoUvbsa6QNKte8NJ8CHr7zGg84KwzwfyBK0s/lsySHgxqSK44PcKSwqTp1LQLio/sskrXzHfWwCyUcuQatH3ehXlUBfpniUozBKE/nHnxpEA52br4xZ3aW4Z7zF7s6nfVKo9nG9cXVIl6HPw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=LEugYbsC; arc=none smtp.client-ip=115.124.30.111 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="LEugYbsC" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1740466614; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=T6xkjDjtY7QYfVEzscO1gyxYmDDVuGprPC6v4IGloFQ=; b=LEugYbsCrtVyzRn+C6sFG2K3TxyoIlpDw1T+a94fj9BDPoulJ4/1LtFTj5fbYi1NH31HvTbTViTT1ork+d0nN3+mzwsGnc5Fh7FLdZBLIQZs6sqb7dzKnPF+tGkSG3cvZXy7/UIcrPNwsVHpSEC007/6M3UfXDkYtNKzU8S+jCs= Received: from 30.74.130.67(mailfrom:dtcccc@linux.alibaba.com fp:SMTPD_---0WQDcYiu_1740466603 cluster:ay36) by smtp.aliyun-inc.com; Tue, 25 Feb 2025 14:56:53 +0800 Message-ID: <61589e0e-a3d7-490c-8bba-a1ce25f585c3@linux.alibaba.com> Date: Tue, 25 Feb 2025 14:56:52 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH 2/2] sched/fair: Fix premature check of WAKEUP_PREEMPTION To: Vincent Guittot Cc: Madadi Vineeth Reddy , Peter Zijlstra , Ingo Molnar , Juri Lelli , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Josh Don , "open list:SCHEDULER" , Abel Wu References: <20250221111226.64455-1-wuyun.abel@bytedance.com> <20250221111226.64455-3-wuyun.abel@bytedance.com> <6097164a-aa99-4869-b666-9dc7018c1f96@bytedance.com> <9d9d7432-9a5d-4216-ac53-a0f333a35d8f@bytedance.com> <83f8b833-af79-4d77-a179-5065aec994dc@bytedance.com> Content-Language: en-US From: Tianchen Ding In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2/24/25 9:47 PM, Vincent Guittot wrote: [...] > > Or we should just remove it. I'm curious to know who used it during > the last couple of years ? Having in mind that lazy preemption adds > another level as check_preempt_wakeup_fair() uses it so sched-idle > tasks might not always be immediately preempted anyway. > I just remembered that I've mentioned this issue in another thread[1] before. Can we do preempt SCHED_IDLE immediately even in PREEMPT_LAZY? (to achieve better response time for SCHED_NORMAL) [1] https://lore.kernel.org/all/8e6f02a0-2bd0-4e75-9055-2cb7c508ce4e@linux.alibaba.com/