From patchwork Wed Sep 23 18:11:25 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: 11795443 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 320DD139A for ; Wed, 23 Sep 2020 18:18:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0DCA423772 for ; Wed, 23 Sep 2020 18:18:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="bhE1nt8m" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726537AbgIWSRp (ORCPT ); Wed, 23 Sep 2020 14:17:45 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:40593 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726689AbgIWSRo (ORCPT ); Wed, 23 Sep 2020 14:17:44 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600885063; 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=6VBjsMo44nBEzcbomAkY1iDbxWkCmiCxCVDrlCHo4bI=; b=bhE1nt8mkF1LyXGuk/PL2Q11tZQt3ZQstMSvtAvjLeWG/9Tj3alXI1wHu7GeMy+RdtA4gX 81qRM8ZjVJ88EqaeTvTqDvrlHP6sYTUYvGngny3E2eTFR1tLdU8DwXIcMMtW0hwbBv7hVT 3ovYG78QRZxWvF64s+kAT7OClhzVvKQ= 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-354-JtQTr2bZPVidisWtiOzHBQ-1; Wed, 23 Sep 2020 14:17:39 -0400 X-MC-Unique: JtQTr2bZPVidisWtiOzHBQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B57FB64088; Wed, 23 Sep 2020 18:17:36 +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 E051C5C1C7; Wed, 23 Sep 2020 18:17:34 +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, jerinj@marvell.com, mathias.nyman@intel.com, jiri@nvidia.com, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org Subject: [PATCH v2 3/4] i40e: limit msix vectors based on housekeeping CPUs Date: Wed, 23 Sep 2020 14:11:25 -0400 Message-Id: <20200923181126.223766-4-nitesh@redhat.com> In-Reply-To: <20200923181126.223766-1-nitesh@redhat.com> References: <20200923181126.223766-1-nitesh@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org In a realtime environment, it is essential to isolate unwanted IRQs from isolated CPUs to prevent latency overheads. Creating MSIX vectors only based on the online CPUs could lead to a potential issue on an RT setup that has several isolated CPUs but a very few housekeeping CPUs. This is because in these kinds of setups an attempt to move the IRQs to the limited housekeeping CPUs from isolated CPUs might fail due to the per CPU vector limit. This could eventually result in latency spikes because of the IRQs that we fail to move from isolated CPUs. This patch prevents i40e to create vectors only based on online CPUs by using hk_num_online_cpus() instead. Signed-off-by: Nitesh Narayan Lal Reviewed-by: Marcelo Tosatti Acked-by: Jesse Brandeburg --- drivers/net/ethernet/intel/i40e/i40e_main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c index 2e433fdbf2c3..fcb6fa3707e0 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_main.c +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c @@ -5,6 +5,7 @@ #include #include #include +#include #include /* Local includes */ @@ -11002,7 +11003,7 @@ static int i40e_init_msix(struct i40e_pf *pf) * will use any remaining vectors to reach as close as we can to the * number of online CPUs. */ - cpus = num_online_cpus(); + cpus = hk_num_online_cpus(); pf->num_lan_msix = min_t(int, cpus, vectors_left / 2); vectors_left -= pf->num_lan_msix;