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 A298437DE8D for ; Mon, 23 Mar 2026 21:36:12 +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=1774301774; cv=none; b=Gx1gJmtH80tO9VioaN9tBWju1ffzBPfgW1UTUcdV7dci5iKehUAf3eluvk/LViPxiyrOAGIGBSICwcuzlizSy3WL6fMa+ZTdXA3Q5MvU74oJo5n4k2XC6y7NQb/Dgb51gHQIR8NXMiqskmwO9nGWgzMegqkY2lhrQnak5nXKE7I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774301774; c=relaxed/simple; bh=RqVZqL0CV0t9H98pGARpg6t2/5L6quUpmsj/1VO79HQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=JKVlPb14KzoUDOOCgPX6r9bWSQkQCpGWx2/mD8+FkEc/tRz3sg9d7jaqNIi/5RFDqy2Jv4//NBntXw1BQ1f4fcqjBgmdfMOqMzXMtFSKJyNur0SJTd9fl7N4ea+ngUk+tOw9u+gYefbfLs6q4pJy+SNcaiMI70Li/LUJijDE5yE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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=dhQ4UknO; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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="dhQ4UknO" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1774301771; 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=lkW+Nk4gBBDvIJ4jf1kVSC8/AK2dlm3+gGc8WXSxls0=; b=dhQ4UknO0Qf2fPLgGbBNcl2LnMwyE7OTCkoW//hcUoYsF5jdCy+JPxLVDCeA918ZRZpkCl 78TslSjCvfIMTY1L2D8Z/G3wncueW31ksAL/dIymslVa3t+jOcLViCZoG8Eo+wVx7N9ET3 VdQ9P2Ryuqbm3hhuBgi9EZ8m2LZWkYM= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-475-y2DqP-8fMkSGZtochVGBMQ-1; Mon, 23 Mar 2026 17:36:07 -0400 X-MC-Unique: y2DqP-8fMkSGZtochVGBMQ-1 X-Mimecast-MFC-AGG-ID: y2DqP-8fMkSGZtochVGBMQ_1774301766 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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 mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 95C841800619; Mon, 23 Mar 2026 21:36:06 +0000 (UTC) Received: from [10.22.89.181] (unknown [10.22.89.181]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id F081A1955D71; Mon, 23 Mar 2026 21:36:05 +0000 (UTC) Message-ID: Date: Mon, 23 Mar 2026 17:36:05 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [QUESTION/REGRESSION] Unbound kthreads scheduled on nohz_full CPUs after commit 041ee6f3727a To: sheviks Cc: frederic@kernel.org, linux-kernel@vger.kernel.org References: <98b598f7-cbc6-42bd-bd01-d077549628fd@redhat.com> Content-Language: en-US From: Waiman Long In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 On 3/23/26 12:58 AM, sheviks wrote: > Waiman Long 於 2026年3月23日 週一 05:18 寫道： >> The plan is to make nohz_full also dynamically changeable at run time in >> the future. We are not there yet. Now HK_TYPE_KTHREAD is equivalent to >> HK_TYPE_DOMAIN. >> >> A CPU cannot be considered fully isolated if it is in either >> HK_TYPE_DOMAIN or HK_TYPE_KERNEL_NOISE. Currently, the nohz_full kernel >> parameter can be used to put a set of partially isolated CPUs in the >> nohz_full reservoir. To fully isolate them, some or all of them will be >> need to be put in an isolated cpuset partition. BTW, HK_TYPE_MANAGED_IRQ >> will be made to be dynamic too. >> >> That is my current view. >> > That sounds like a great roadmap. I am very much looking forward to > seeing the final implementation, as making nohz_full and managed IRQs > dynamic would be a significant improvement for runtime isolation > flexibility. > > However, regarding the current state in 7.0rc4, I observed that > HK_TYPE_KTHREAD still appears to be initialized as > HK_TYPE_KERNEL_NOISE rather than HK_TYPE_DOMAIN in the initialization > path. > Perhaps this part of the alignment hasn't been merged into the mainline yet? Yes, I notice that too. I am working on a patch to alias  it to HK_TYPE_DOMAIN instead. Cheers, Longman > > Thanks for the clarification and for your work on this! > Best regards, > Sheviks >