From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:35144 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755194AbeDQQH1 (ORCPT ); Tue, 17 Apr 2018 12:07:27 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stefan Haberland , Keith Busch , Christian Borntraeger , Christoph Hellwig , Sagi Grimberg , Ming Lei , Jens Axboe Subject: [PATCH 4.14 45/49] blk-mq: dont keep offline CPUs mapped to hctx 0 Date: Tue, 17 Apr 2018 17:59:24 +0200 Message-Id: <20180417155717.187039680@linuxfoundation.org> In-Reply-To: <20180417155715.032245882@linuxfoundation.org> References: <20180417155715.032245882@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ming Lei commit bffa9909a6b48d8ca3398dec601bc9162a4020c4 upstream. >>>From commit 4b855ad37194 ("blk-mq: Create hctx for each present CPU), blk-mq doesn't remap queue after CPU topo is changed, that said when some of these offline CPUs become online, they are still mapped to hctx 0, then hctx 0 may become the bottleneck of IO dispatch and completion. This patch sets up the mapping from the beginning, and aligns to queue mapping for PCI device (blk_mq_pci_map_queues()). Cc: Stefan Haberland Cc: Keith Busch Cc: stable@vger.kernel.org Fixes: 4b855ad37194 ("blk-mq: Create hctx for each present CPU) Tested-by: Christian Borntraeger Reviewed-by: Christoph Hellwig Reviewed-by: Sagi Grimberg Signed-off-by: Ming Lei Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- block/blk-mq-cpumap.c | 5 ----- 1 file changed, 5 deletions(-) --- a/block/blk-mq-cpumap.c +++ b/block/blk-mq-cpumap.c @@ -16,11 +16,6 @@ static int cpu_to_queue_index(unsigned int nr_queues, const int cpu) { - /* - * Non present CPU will be mapped to queue index 0. - */ - if (!cpu_present(cpu)) - return 0; return cpu % nr_queues; }