From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752043AbeBAKhX (ORCPT ); Thu, 1 Feb 2018 05:37:23 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50754 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751520AbeBAKhT (ORCPT ); Thu, 1 Feb 2018 05:37:19 -0500 Date: Thu, 1 Feb 2018 18:36:57 +0800 From: Ming Lei To: Don Brace Cc: Laurence Oberman , Thomas Gleixner , Christoph Hellwig , Jens Axboe , "linux-block@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Mike Snitzer Subject: Re: [PATCH 0/2] genirq/affinity: try to make sure online CPU is assgined to irq vector Message-ID: <20180201103651.GA29263@ming.t460p> References: <20180115160345.2611-1-ming.lei@redhat.com> <20180115174036.GA20191@infradead.org> <20180116013043.GA3213@ming.t460p> <1516109317.9574.1.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 16, 2018 at 03:22:18PM +0000, Don Brace wrote: > > -----Original Message----- > > From: Laurence Oberman [mailto:loberman@redhat.com] > > Sent: Tuesday, January 16, 2018 7:29 AM > > To: Thomas Gleixner ; Ming Lei > > Cc: Christoph Hellwig ; Jens Axboe ; > > linux-block@vger.kernel.org; linux-kernel@vger.kernel.org; Mike Snitzer > > ; Don Brace > > Subject: Re: [PATCH 0/2] genirq/affinity: try to make sure online CPU is assgined > > to irq vector > > > > > > It is because of irq_create_affinity_masks(). > > > > > > That still does not answer the question. If the interrupt for a queue > > > is > > > assigned to an offline CPU, then the queue should not be used and > > > never > > > raise an interrupt. That's how managed interrupts have been designed. > > > > > > Thanks, > > > > > > tglx > > > > > > > > > > > > > > > > I captured a full boot log for this issue for Microsemi, I will send it > > to Don Brace. > > I enabled all the HPSA debug and here is snippet > > > > > > .. > > .. > > .. > > 246.751135] INFO: task systemd-udevd:413 blocked for more than 120 > > seconds. > > [  246.788008]       Tainted: G I 4.15.0-rc4.noming+ #1 > > [  246.822380] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" > > disables this message. > > [  246.865594] systemd-udevd D 0 413 411 0x80000004 > > [  246.895519] Call Trace: > > [  246.909713]  ? __schedule+0x340/0xc20 > > [  246.930236]  schedule+0x32/0x80 > > [  246.947905]  schedule_timeout+0x23d/0x450 > > [ 246.970047]  ? find_held_lock+0x2d/0x90 > > [  246.991774]  ? wait_for_completion_io+0x108/0x170 > > [  247.018172]  io_schedule_timeout+0x19/0x40 > > [  247.041208]  wait_for_completion_io+0x110/0x170 > > [  247.067326]  ? wake_up_q+0x70/0x70 > > [  247.086801]  hpsa_scsi_do_simple_cmd+0xc6/0x100 [hpsa] > > [  247.114315]  hpsa_scsi_do_simple_cmd_with_retry+0xb7/0x1c0 [hpsa] > > [  247.146629]  hpsa_scsi_do_inquiry+0x73/0xd0 [hpsa] > > [  247.174118]  hpsa_init_one+0x12cb/0x1a59 [hpsa] > > This trace comes from internally generated discovery commands. No SCSI devices have > been presented to the SML yet. > > At this point we should be running on only one CPU. These commands are meant to use > reply queue 0 which are tied to CPU 0. It's interesting that the patch helps. > > However, I was wondering if you could inspect the iLo IML logs and send the > AHS logs for inspection. Hello Don, Now the patch has been merged to linus tree as: 84676c1f21e8ff54b ("genirq/affinity: assign vectors to all possible CPUs") and it breaks Laurence's machine completely, :-( I just take a look at HPSA's code, and found that reply queue is chosen in the following way in most of code path: if (likely(reply_queue == DEFAULT_REPLY_QUEUE)) cp->ReplyQueue = smp_processor_id() % h->nreply_queues; h->nreply_queues is the msix vector number which is returned from pci_alloc_irq_vectors(), and now some of vectors may be mapped to all offline CPUs, for example, one processor isn't plugged to socket. If I understand correctly, 'cp->ReplyQueue' is aligned to one irq vector, and the command is expected by handled via that irq vector, is it right? If yes, now I guess this way can't work any more if number of online CPUs is >= h->nreply_queues, and you may need to check the cpu affinity of one vector before choosing the reply queue, and block/blk-mq-pci.c may be helpful for you. Thanks, Ming