From patchwork Mon Sep 28 18:35:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nitesh Narayan Lal X-Patchwork-Id: 11804559 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id ECBF6112E for ; Mon, 28 Sep 2020 18:36:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C6F20207D8 for ; Mon, 28 Sep 2020 18:36:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="cajg8/6U" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726751AbgI1SgT (ORCPT ); Mon, 28 Sep 2020 14:36:19 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:58547 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726500AbgI1SgS (ORCPT ); Mon, 28 Sep 2020 14:36:18 -0400 Dkim-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1601318176; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:in-reply-to:in-reply-to:references:references; bh=iL0bUDw4mzTbRn0mPQir1H2iMDlMMQuuu3RzcEtjrtI=; b=cajg8/6U5c3aJCedYXkZBkE8ecsZ6nR6lI24rg8ExZyStm1e0qFUcHR4jihv1Aj8J1tGKq rm0qHa2pk/Ux9gqxzlt5ptph1qG8+/RL83yHuBiocE8vZJ8H+tS7kCCzLIz6HA22U0+o1y 2/dMzExE3sJBoBokho9paehMuev7TYg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-205-QOoB4A-NNji0hBs9kJXzaw-1; Mon, 28 Sep 2020 14:36:14 -0400 X-MC-Unique: QOoB4A-NNji0hBs9kJXzaw-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 28462ADC25; Mon, 28 Sep 2020 18:36:08 +0000 (UTC) Received: from virtlab719.virt.lab.eng.bos.redhat.com (virtlab719.virt.lab.eng.bos.redhat.com [10.19.153.15]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4E07860C13; Mon, 28 Sep 2020 18:36:06 +0000 (UTC) From: Nitesh Narayan Lal To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-pci@vger.kernel.org, intel-wired-lan@lists.osuosl.org, frederic@kernel.org, mtosatti@redhat.com, sassmann@redhat.com, jesse.brandeburg@intel.com, lihong.yang@intel.com, helgaas@kernel.org, nitesh@redhat.com, jeffrey.t.kirsher@intel.com, jacob.e.keller@intel.com, jlelli@redhat.com, hch@infradead.org, bhelgaas@google.com, mike.marciniszyn@intel.com, dennis.dalessandro@intel.com, thomas.lendacky@amd.com, jiri@nvidia.com, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, lgoncalv@redhat.com Subject: [PATCH v4 1/4] sched/isolation: API to get number of housekeeping CPUs Date: Mon, 28 Sep 2020 14:35:26 -0400 Message-Id: <20200928183529.471328-2-nitesh@redhat.com> In-Reply-To: <20200928183529.471328-1-nitesh@redhat.com> References: <20200928183529.471328-1-nitesh@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Introduce a new API housekeeping_num_online_cpus(), that can be used to retrieve the number of online housekeeping CPUs based on the housekeeping flag passed by the caller. Some of the consumers for this API are the device drivers that were previously relying only on num_online_cpus() to determine the number of MSIX vectors to create. In real-time environments to minimize interruptions to isolated CPUs, all device-specific IRQ vectors are often moved to the housekeeping CPUs, having excess vectors could cause housekeeping CPU to run out of IRQ vectors. Signed-off-by: Nitesh Narayan Lal --- include/linux/sched/isolation.h | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h index cc9f393e2a70..e021b1846c1d 100644 --- a/include/linux/sched/isolation.h +++ b/include/linux/sched/isolation.h @@ -57,4 +57,13 @@ static inline bool housekeeping_cpu(int cpu, enum hk_flags flags) return true; } +static inline unsigned int housekeeping_num_online_cpus(enum hk_flags flags) +{ +#ifdef CONFIG_CPU_ISOLATION + if (static_branch_unlikely(&housekeeping_overridden)) + return cpumask_weight(housekeeping_cpumask(flags)); +#endif + return num_online_cpus(); +} + #endif /* _LINUX_SCHED_ISOLATION_H */