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=-7.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 AD4DDC07E9C for ; Wed, 7 Jul 2021 10:53:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9071F61CAA for ; Wed, 7 Jul 2021 10:53:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231220AbhGGK4J (ORCPT ); Wed, 7 Jul 2021 06:56:09 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:47457 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231357AbhGGK4J (ORCPT ); Wed, 7 Jul 2021 06:56:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625655209; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=K+EWc05GzZnbdXQqGI6q0RxvYbPzZlg3v0dwhXJ+Y2E=; b=IVfPVy+YTFqfv0UqRdn99UXw/3O6H7njcTdbcdGU6MJsvSXN9Y7rDHAsb6hTJme7Rt2SiY bqQ5zdzjwrT4A5SOosRSwH/bnPMWCP7qyGQXb9YMQkRaN/guOhu+LOGH0mm/4W60GmXfQz 8CXWxOIJ5xHB5CbKwkxUNmIq2MS36QA= 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-442-rXwPL51rMsO23RrVkwLSlA-1; Wed, 07 Jul 2021 06:53:25 -0400 X-MC-Unique: rXwPL51rMsO23RrVkwLSlA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id ED228802C89; Wed, 7 Jul 2021 10:53:23 +0000 (UTC) Received: from T590 (ovpn-12-84.pek2.redhat.com [10.72.12.84]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9147069CB8; Wed, 7 Jul 2021 10:53:07 +0000 (UTC) Date: Wed, 7 Jul 2021 18:53:02 +0800 From: Ming Lei To: Hannes Reinecke Cc: Christoph Hellwig , John Garry , Jens Axboe , "Martin K . Petersen" , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, Sagi Grimberg , Daniel Wagner , Wen Xiong , Keith Busch , Damien Le Moal Subject: Re: [PATCH V2 3/6] scsi: add flag of .use_managed_irq to 'struct Scsi_Host' Message-ID: References: <20210702150555.2401722-1-ming.lei@redhat.com> <20210702150555.2401722-4-ming.lei@redhat.com> <47fc5ed1-29e3-9226-a111-26c271cb6d90@huawei.com> <20210706053719.GA17027@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Jul 06, 2021 at 12:32:27PM +0200, Hannes Reinecke wrote: > On 7/6/21 9:41 AM, Ming Lei wrote: > > On Tue, Jul 06, 2021 at 07:37:19AM +0200, Christoph Hellwig wrote: > > > On Mon, Jul 05, 2021 at 05:55:49PM +0800, Ming Lei wrote: > > > > The thing is that blk_mq_pci_map_queues() is allowed to be called for > > > > non-managed irqs. Also some managed irq consumers don't use blk_mq_pci_map_queues(). > > > > > > > > So this way just provides hint about managed irq uses, but we really > > > > need to get this flag set if driver uses managed irq. > > > > > > blk_mq_pci_map_queues is absolutely intended to only be used by > > > managed irqs. I wonder if we can enforce that somehow? > > > > It may break some scsi drivers. > > > > And blk_mq_pci_map_queues() just calls pci_irq_get_affinity() to > > retrieve the irq's affinity, and the irq can be one non-managed irq, > > which affinity is set via either irq_set_affinity_hint() from kernel > > or /proc/irq/. > > > But that's static, right? IE blk_mq_pci_map_queues() will be called once > during module init; so what happens if the user changes the mapping later > on? How will that be transferred to the driver? Yeah, that may not work well enough, but still works since non-managed irq supports migration. And there are several SCSI drivers which provide module parameter to enable/disable managed irq, meantime blk_mq_pci_map_queues() is always called for mapping queues. Thanks, Ming