From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751944AbdAMPEH (ORCPT ); Fri, 13 Jan 2017 10:04:07 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:60359 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751739AbdAMPEF (ORCPT ); Fri, 13 Jan 2017 10:04:05 -0500 Date: Fri, 13 Jan 2017 08:03:58 -0700 From: Jens Axboe To: Hannes Reinecke CC: , , , Subject: Re: [PATCHSET v6] blk-mq scheduling framework Message-ID: <20170113150358.GC23338@kernel.dk> References: <1484170803-9311-1-git-send-email-axboe@fb.com> <5850a4ad-74a1-8d30-e865-fbd35679e84f@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <5850a4ad-74a1-8d30-e865-fbd35679e84f@suse.de> X-Originating-IP: [192.168.54.13] X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-01-13_09:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 13 2017, Hannes Reinecke wrote: > On 01/13/2017 09:15 AM, Hannes Reinecke wrote: > > On 01/11/2017 10:39 PM, Jens Axboe wrote: > >> Another year, another posting of this patchset. The previous posting > >> was here: > >> > >> https://www.spinics.net/lists/kernel/msg2406106.html > >> > >> (yes, I've skipped v5, it was fixes on top of v4, not the rework). > >> > >> I've reworked bits of this to get rid of the shadow requests, thanks > >> to Bart for the inspiration. The missing piece, for me, was the fact > >> that we have the tags->rqs[] indirection array already. I've done this > >> somewhat differently, though, by having the internal scheduler tag > >> map be allocated/torn down when an IO scheduler is attached or > >> detached. This also means that when we run without a scheduler, we > >> don't have to do double tag allocations, it'll work like before. > >> > >> The patchset applies on top of 4.10-rc3, or can be pulled here: > >> > >> git://git.kernel.dk/linux-block blk-mq-sched.6 > >> > > Well ... something's wrong here on my machine: > > > > [ 39.886886] ------------[ cut here ]------------ > > [ 39.886895] WARNING: CPU: 9 PID: 62 at block/blk-mq.c:342 > > __blk_mq_finish_request+0x124/0x140 > > [ 39.886895] Modules linked in: sd_mod ahci uhci_hcd ehci_pci > > mpt3sas(+) libahci ehci_hcd serio_raw crc32c_intel raid_class drm libata > > usbcore hpsa usb_common scsi_transport_sas sg dm_multipath dm_mod > > scsi_dh_rdac scsi_dh_emc scsi_dh_alua autofs4 > > [ 39.886910] CPU: 9 PID: 62 Comm: kworker/u130:0 Not tainted > > 4.10.0-rc3+ #528 > > [ 39.886911] Hardware name: HP ProLiant ML350p Gen8, BIOS P72 09/08/2013 > > [ 39.886917] Workqueue: events_unbound async_run_entry_fn > > [ 39.886918] Call Trace: > > [ 39.886923] dump_stack+0x85/0xc9 > > [ 39.886927] __warn+0xd1/0xf0 > > [ 39.886928] warn_slowpath_null+0x1d/0x20 > > [ 39.886930] __blk_mq_finish_request+0x124/0x140 > > [ 39.886932] blk_mq_finish_request+0x55/0x60 > > [ 39.886934] blk_mq_sched_put_request+0x78/0x80 > > [ 39.886936] blk_mq_free_request+0xe/0x10 > > [ 39.886938] blk_put_request+0x25/0x60 > > [ 39.886944] __scsi_execute.isra.24+0x104/0x160 > > [ 39.886946] scsi_execute_req_flags+0x94/0x100 > > [ 39.886948] scsi_report_opcode+0xab/0x100 > > > > checking ... > > > Ah. > Seems like the elevator switch races with device setup: Huh, funky, haven't seen that. I'll see if I can reproduce it here. I don't have SCAN_ASYNC turned on, on my test box. -- Jens Axboe