From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 C521114A4DB for ; Wed, 3 Apr 2024 15:10:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712157048; cv=none; b=cpDkfxjp5OrhNERA0klG+0FJMDh2uUgBrXlI2yx91azvJJnpJZajSAZTvxCvyZdww64gBzUJX24q0vV0CgrWzV1P4nfTIFw8s2WkwAur/QKKSDXFuKlh3a364z7YnST8Gg5EzU8H5squ4ikmBGBjKT8s5RhWYlZm39tRVXE2vPI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712157048; c=relaxed/simple; bh=anwzlEybqYMGwaD+F9GCbHmbnWkGkyE/W+MYH3vfNAU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=UQpW2U7HzGUUpVHxSNj+dR+iShOvcCSt7Y+TjuWOYfRJxvh3PjZTgHzLVTGqTfPolYYfC9onuIIbNaCQehuj9o4uQSX+31xxc/0LiF0GuJTC3ApgVXElYDJRYLVJCur9SpEZGBOGSkq8NePN5S42CjgJaQ454axTfzR0ATMll74= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=bDPLt6si; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="bDPLt6si" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1712157045; h=from:from: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=vcTH6u0Rlg+BVw+a7Jg/5/hidJ0AE0bMPe3NIsD6EkA=; b=bDPLt6sibniL94jXKHcQabn5v15dNcmY8O0sa5Yq9VKF17RLzt/xHmVHNZDP1EQzBLBdus TipUGdVveH8Jx2/5Ga2G3XRs9ZLsjsTMUrCigRWye8ceT70dQlwsHGOrRjOVicwMGWUHu6 xrZBfTw67qlD2Rbk7U3GZ7gV5yrqjRI= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-453-5XXZIlPLMNmZ6TxIZUFe7A-1; Wed, 03 Apr 2024 11:10:40 -0400 X-MC-Unique: 5XXZIlPLMNmZ6TxIZUFe7A-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E328A80B1E3; Wed, 3 Apr 2024 15:10:38 +0000 (UTC) Received: from [10.22.33.218] (unknown [10.22.33.218]) by smtp.corp.redhat.com (Postfix) with ESMTP id 80B2B2166B31; Wed, 3 Apr 2024 15:10:37 +0000 (UTC) Message-ID: Date: Wed, 3 Apr 2024 11:10:37 -0400 Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] cgroup/cpuset: Make cpuset hotplug processing synchronous Content-Language: en-US To: =?UTF-8?Q?Michal_Koutn=C3=BD?= Cc: Valentin Schneider , Tejun Heo , Zefan Li , Johannes Weiner , Thomas Gleixner , Peter Zijlstra , "Rafael J. Wysocki" , Len Brown , Pavel Machek , Shuah Khan , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-pm@vger.kernel.org, linux-kselftest@vger.kernel.org, Frederic Weisbecker , "Paul E. McKenney" , Ingo Molnar , Anna-Maria Behnsen , Alex Shi , Vincent Guittot , Barry Song References: <20240401145858.2656598-1-longman@redhat.com> <20240401145858.2656598-2-longman@redhat.com> <548efd52-e45f-41fa-a477-bc5112d7b00c@redhat.com> <7e62b37d-6c9c-4e55-a01a-175695475cb5@redhat.com> <620d1b70-cfbc-4b76-ad04-b3be559afd56@redhat.com> From: Waiman Long In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.6 On 4/3/24 10:56, Michal Koutný wrote: > On Wed, Apr 03, 2024 at 10:47:33AM -0400, Waiman Long wrote: >> should be rare these days as it will only apply in the case of cgroup >> v1 under certain condtion, > Could the migration be simply omitted it those special cases? > > (Tasks remain in cpusets with empty cpusets -- that already happens in > with the current patch before workqueue is dispatched.) The tasks should not be runnable if there is no CPUs left in their v1 cpuset. Migrating them to a parent with runnable CPUs is the current way which I don't want to break. Alternatively, we could force it to fall back to cgroup v2 behavior using the CPUs in their parent cpuset. Cheers, Longman > > Michal