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=-5.2 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,URIBL_BLOCKED,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 04C4BC61DD8 for ; Mon, 16 Nov 2020 17:27:11 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 7C73B221FD for ; Mon, 16 Nov 2020 17:27:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="RoVJQ23U" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7C73B221FD 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=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject: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=Ac1ra0UgAOBeDpJFw9WUmAZd5FUQwj637YFn7ICp73Q=; b=RoVJQ23UDMIYgQtHXdKYlYBjm iQTL/fwynAoVqzce5LccB5pgH6RUzLtmSV3MLmxMvxosuKueoj3pquWeOQWy5pRpHy39RU6M5tpnr vKwqXdFmUBCa+6NFzqsNZftTqHISfVHV134BLme4YNvcASKa9sIMXFzgQDFtN3vrCJ/q9n+NFzWDy GUCwLg2VNbH920OVJDOeEMoKyZ+0ax7AHv3sYBs3TMA8W2da2BAip44+LDFv3URCKYfYs/nMLYsap 6n6fK3Nv+dHLbXkiBcU0gq3PaBaYf6Ljsw3+gDwptUgcwOiVdPVB2gWMgswiPiL9NTR+B8iyNpxBv p1uhzhoOQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1keiHS-0008UB-NN; Mon, 16 Nov 2020 17:27:06 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1keiHP-0008Sv-GQ for linux-nvme@lists.infradead.org; Mon, 16 Nov 2020 17:27:04 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 9A1A46736F; Mon, 16 Nov 2020 18:26:58 +0100 (CET) Date: Mon, 16 Nov 2020 18:26:58 +0100 From: Christoph Hellwig To: Ming Lei Subject: Re: [PATCH 1/3] blk-mq: add new API of blk_mq_hctx_set_fq_lock_class Message-ID: <20201116172658.GJ22007@lst.de> References: <20201112075526.947079-1-ming.lei@redhat.com> <20201112075526.947079-2-ming.lei@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201112075526.947079-2-ming.lei@redhat.com> 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-20201116_122703_692942_FEAB67EB X-CRM114-Status: GOOD ( 13.70 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jens Axboe , Bart Van Assche , Qian Cai , John Garry , linux-nvme@lists.infradead.org, Kashyap Desai , linux-block@vger.kernel.org, Sumit Saxena , Hannes Reinecke , Christoph Hellwig 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 Thu, Nov 12, 2020 at 03:55:24PM +0800, Ming Lei wrote: > flush_end_io() may be called recursively from some driver, such as > nvme-loop, so lockdep may complain 'possible recursive locking'. > Commit b3c6a5997541("block: Fix a lockdep complaint triggered by > request queue flushing") tried to address this issue by assigning > dynamically allocated per-flush-queue lock class. This solution > adds synchronize_rcu() for each hctx's release handler, and causes > horrible SCSI MQ probe delay(more than half an hour on megaraid sas). > > Add new API of blk_mq_hctx_set_fq_lock_class() for these drivers, so > we just need to use driver specific lock class for avoiding the > lockdep warning of 'possible recursive locking'. I'd turn this into an inline function to avoid the (although very minimal) cost when LOCKDEP is not enabled. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme