From nobody Sun Nov 24 02:44:16 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 15346199BC for ; Fri, 8 Nov 2024 04:29:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731040189; cv=none; b=EOWnwHBAS82sOJeXOdIdQ8UcPEG7csT/pkIB8VZY/8yKY2Zt+PNB08SB/OApP6iOILkcNxV//UxqVZyCrYnGZh6qQ20YisjnjidbSdkASWYLKuROPEXQYdPfoa8LYu5qFwL9FloB9OjpFmaf8aI05ZFTpp333dEmvE3bZRDYFqo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731040189; c=relaxed/simple; bh=2ETS86wh1T9gkfSbS2Iz2PhobS0UrZnbDFYac9TU6zE=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=XvQ3PAkBF8uAUskid8wysIiM8bQfaS6O/Ob2Rdg7QWULyf8sqgrrhNI+6W0V4Qhmy//1M2hY1cRO7aNnglIC0oWJTDR7lJ1jWFsalGbGhuQqFherBHF8TlFBrUn53qGXA9+XpAoHXP+TaVBhRnB1DvOYRl72dsmAmiSe5UPt85g= 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=gcbwLxRW; arc=none smtp.client-ip=170.10.133.124 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="gcbwLxRW" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1731040185; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=+4xzCVIv4+K0HVgfcCSdshNv9x+PRjK8RaOzmppLwds=; b=gcbwLxRWwofpp6dtHrySch1uuN+hlW3olHc3xYeHvK+Y2fcPRqrALR39Wo9hC5pb+gE3um uSlgDdCj6S2iv7y1kIfLU6Zht+9aeKdoJAXFW6/0FenhM7ZgESvyZCITrpMPPQJaoC1KiV CQyNktWft9w6xaQbYpUicRMENyl4o7s= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-554-a4EviaSuMta1VFrtzGXC1w-1; Thu, 07 Nov 2024 23:29:44 -0500 X-MC-Unique: a4EviaSuMta1VFrtzGXC1w-1 X-Mimecast-MFC-AGG-ID: a4EviaSuMta1VFrtzGXC1w 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-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 59E031955EE9; Fri, 8 Nov 2024 04:29:42 +0000 (UTC) Received: from llong-thinkpadp16vgen1.westford.csb (unknown [10.22.80.175]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 7EA181953880; Fri, 8 Nov 2024 04:29:39 +0000 (UTC) From: Waiman Long To: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider Cc: linux-kernel@vger.kernel.org, Phil Auld , Joel Fernandes , Waiman Long Subject: [PATCH] sched/deadline: Skip overflow check if 0 capacity Date: Thu, 7 Nov 2024 23:29:24 -0500 Message-ID: <20241108042924.520458-1-longman@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Content-Type: text/plain; charset="utf-8" By properly setting up a 1-cpu sched domain (partition) with no task, it was found that offlining that particular CPU failed because dl_bw_check_overflow() in cpuset_cpu_inactive() returned -EBUSY. This is due to the fact that dl_bw_capacity() return 0 as the sched domain has no active CPU causing a false positive in the overflow check. Fix this corner case by skipping the __dl_overflow() check in dl_bw_manage() when the returned capacity is 0. Signed-off-by: Waiman Long Reported-by: Waiman Long Tested-by: Waiman Long