From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61654C433E1 for ; Tue, 14 Jul 2020 10:43:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4832C22203 for ; Tue, 14 Jul 2020 10:43:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726375AbgGNKnS (ORCPT ); Tue, 14 Jul 2020 06:43:18 -0400 Received: from mx2.suse.de ([195.135.220.15]:53624 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725884AbgGNKnP (ORCPT ); Tue, 14 Jul 2020 06:43:15 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 875B7ACDB; Tue, 14 Jul 2020 10:43:15 +0000 (UTC) Subject: Re: [PATCH RFC v7 12/12] hpsa: enable host_tagset and switch to MQ To: Ming Lei , John Garry Cc: don.brace@microsemi.com, axboe@kernel.dk, jejb@linux.ibm.com, martin.petersen@oracle.com, kashyap.desai@broadcom.com, sumit.saxena@broadcom.com, bvanassche@acm.org, hare@suse.com, hch@lst.de, shivasharan.srikanteshwara@broadcom.com, linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, esc.storagedev@microsemi.com, chenxiang66@hisilicon.com, megaraidlinux.pdl@broadcom.com References: <1591810159-240929-1-git-send-email-john.garry@huawei.com> <1591810159-240929-13-git-send-email-john.garry@huawei.com> <939891db-a584-1ff7-d6a0-3857e4257d3e@huawei.com> <3b3ead84-5d2f-dcf2-33d5-6aa12d5d9f7e@suse.de> <4319615a-220b-3629-3bf4-1e7fd2d27b92@huawei.com> <20200714080631.GA600766@T590> <3584bcc3-830a-d50d-bb55-8ac0b686cdc0@huawei.com> <20200714101432.GA602708@T590> From: Hannes Reinecke Openpgp: preference=signencrypt Autocrypt: addr=hare@suse.de; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20200714101432.GA602708@T590> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On 7/14/20 12:14 PM, Ming Lei wrote: > On Tue, Jul 14, 2020 at 10:53:32AM +0100, John Garry wrote: >> On 14/07/2020 09:06, Ming Lei wrote: >>>> v7 is here: >>>> >>>> https://github.com/hisilicon/kernel-dev/commits/private-topic-blk-mq-shared-tags-rfc-v7 >>>> >>>> So that should be good to test with for now. >>>> >>>> And I was going to ask this same question about smartpqi, so can you please >>>> let me know about this one? >> >> Hi Ming, >> >>> smartpqi is real MQ HBA, do you need any change wrt. shared tags? >> >> Is it really? > > Yes, it is. > > pqi_register_scsi(): > shost->nr_hw_queues = ctrl_info->num_queue_groups; > > pqi_enable_msix_interrupts(): > num_vectors_enabled = pci_alloc_irq_vectors(ctrl_info->pci_dev, > PQI_MIN_MSIX_VECTORS, ctrl_info->num_queue_groups, > PCI_IRQ_MSIX | PCI_IRQ_AFFINITY); > >> >> As I see, today it maintains a single tagset per HBA. So Hannes' change in > > No, each hw queue has one independent tagset for smartpqi. > Has it really? The code has this: static struct pqi_io_request *pqi_alloc_io_request( struct pqi_ctrl_info *ctrl_info) { struct pqi_io_request *io_request; u16 i = ctrl_info->next_io_request_slot; /* benignly racy */ while (1) { io_request = &ctrl_info->io_request_pool[i]; if (atomic_inc_return(&io_request->refcount) == 1) break; atomic_dec(&io_request->refcount); i = (i + 1) % ctrl_info->max_io_slots; } which means that at least the driver assumes a host-wide tagset. Looking at the code the HW _should_ support per-queue tagsets (it's PQI, after all), but this doesn't seem to be carried over for the entire driver; possibly due to legacy concerns. Don should be able to shed some light here. Meanwhile we have to assume that the _driver_ uses a per-host tagset; we might be able to convert it to a per-queue tagset, but that looks like a major update of the driver itself. Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), GF: Felix Imendörffer