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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 2FFFBC6377D for ; Wed, 21 Jul 2021 20:33:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0EEE760FF4 for ; Wed, 21 Jul 2021 20:33:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229981AbhGUTw0 (ORCPT ); Wed, 21 Jul 2021 15:52:26 -0400 Received: from verein.lst.de ([213.95.11.211]:60006 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230173AbhGUTw0 (ORCPT ); Wed, 21 Jul 2021 15:52:26 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 691A967373; Wed, 21 Jul 2021 22:32:59 +0200 (CEST) Date: Wed, 21 Jul 2021 22:32:59 +0200 From: Christoph Hellwig To: Thomas Gleixner Cc: Christoph Hellwig , John Garry , Ming Lei , Jens Axboe , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, Greg Kroah-Hartman , Bjorn Helgaas , linux-pci@vger.kernel.org, Sagi Grimberg , Daniel Wagner , Wen Xiong , Hannes Reinecke , Keith Busch Subject: Re: [PATCH V4 1/3] driver core: mark device as irq affinity managed if any irq is managed Message-ID: <20210721203259.GA18960@lst.de> References: <20210715120844.636968-1-ming.lei@redhat.com> <20210715120844.636968-2-ming.lei@redhat.com> <5e534fdc-909e-39b2-521d-31f643a10558@huawei.com> <20210719094414.GC431@lst.de> <87lf60cevz.ffs@nanos.tec.linutronix.de> <20210721072445.GA11257@lst.de> <871r7rqva6.ffs@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <871r7rqva6.ffs@nanos.tec.linutronix.de> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Wed, Jul 21, 2021 at 10:14:25PM +0200, Thomas Gleixner wrote: > https://lore.kernel.org/r/87o8bxcuxv.ffs@nanos.tec.linutronix.de > > TLDR: virtio allocates ONE irq on msix_enable() and then when the guest > actually unmasks another entry (e.g. request_irq()), it tears down the > allocated one and set's up two. On the third one this repeats .... > > There are only two options: > > 1) allocate everything upfront, which is undesired > 2) append entries, which might need locking, but I'm still trying to > avoid that > > There is another problem vs. vector exhaustion which can't be fixed that > way, but that's a different story. FTI, NVMe is similar. We need one IRQ to setup the admin queue, which is used to query/set how many I/O queues are supported. Just two steps though and not unbound. 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=-6.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 1ECF6C6377A for ; Wed, 21 Jul 2021 20:33:31 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8AC0061003 for ; Wed, 21 Jul 2021 20:33:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8AC0061003 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=j7R6gz5lsgnB6jv1yxJO50d+4imHLFJHuDaNt1UBpao=; b=bZJCi4hS6/ESz/ yRQIUcIQEay89MtQSFM5qJYACzOHC6TgXT0seNaDwlVvziU11SPDCwKXUmXfM2F3HxLdgvTkXZCSF dcwFNvWD33fCM71OlBrYPuI7ciN9DFt81p6/wexys5Iev2BqwWwSS+26SaNm19pQ0SFFW5+X61xlS LkUfTMEfpDwEIUvJA+m0ojpaLpLvEg/ApZveHRXY42CwTrHJRROp+4/nqCjOYUjOAkZ2MdnptRzVL z3fB7BOAOahWRSNu2ozyWd+J+MY3we4VF9FCV5fLlbKDxyDKZz4q69d+881v7taJgofj7udw5Q+FJ zCPJwyRCM45qLXzTV5hw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1m6Ity-00H80w-7a; Wed, 21 Jul 2021 20:33:10 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1m6Itt-00H7zY-8l for linux-nvme@lists.infradead.org; Wed, 21 Jul 2021 20:33:08 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 691A967373; Wed, 21 Jul 2021 22:32:59 +0200 (CEST) Date: Wed, 21 Jul 2021 22:32:59 +0200 From: Christoph Hellwig To: Thomas Gleixner Cc: Christoph Hellwig , John Garry , Ming Lei , Jens Axboe , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, Greg Kroah-Hartman , Bjorn Helgaas , linux-pci@vger.kernel.org, Sagi Grimberg , Daniel Wagner , Wen Xiong , Hannes Reinecke , Keith Busch Subject: Re: [PATCH V4 1/3] driver core: mark device as irq affinity managed if any irq is managed Message-ID: <20210721203259.GA18960@lst.de> References: <20210715120844.636968-1-ming.lei@redhat.com> <20210715120844.636968-2-ming.lei@redhat.com> <5e534fdc-909e-39b2-521d-31f643a10558@huawei.com> <20210719094414.GC431@lst.de> <87lf60cevz.ffs@nanos.tec.linutronix.de> <20210721072445.GA11257@lst.de> <871r7rqva6.ffs@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <871r7rqva6.ffs@nanos.tec.linutronix.de> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210721_133305_504307_91C146B1 X-CRM114-Status: GOOD ( 17.96 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Wed, Jul 21, 2021 at 10:14:25PM +0200, Thomas Gleixner wrote: > https://lore.kernel.org/r/87o8bxcuxv.ffs@nanos.tec.linutronix.de > > TLDR: virtio allocates ONE irq on msix_enable() and then when the guest > actually unmasks another entry (e.g. request_irq()), it tears down the > allocated one and set's up two. On the third one this repeats .... > > There are only two options: > > 1) allocate everything upfront, which is undesired > 2) append entries, which might need locking, but I'm still trying to > avoid that > > There is another problem vs. vector exhaustion which can't be fixed that > way, but that's a different story. FTI, NVMe is similar. We need one IRQ to setup the admin queue, which is used to query/set how many I/O queues are supported. Just two steps though and not unbound. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme