From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793217645; b=QMTMW1B2mkLc+8g5LUtIGVtzFibln3EnGXBCTpI0KFW+EFdyDfZ30DwVKW7Se/ZMLCX+ /jgbT7UemVlHCIem9/aYTjR4rgBxGN3ZcNrXH6+2BWD2j1oiCMzpy1gdFhd4C2q5NS4HA 2L+hXwJCSd4ONYWwDXlucpBqM0Xp878O1aLQlxTneQgbOYUUEVylCEkd9rkFQXtLYiUPd CQITLM7oBt9rsD9uCqgL16pHWxOCjvPBDiLc8CvHVMaVN39LzLHYjr8DstWZXD/X+7Uqi DbiA7ZN6IHaslmuidgmd4o9SKx/TUpS1aHTM4H+oKWrQYkiv0FdgkJxZtxOpalJf0CA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793217645; h=Received:DKIM-Signature:Date:Message-ID:From:To:Cc:Subject: In-Reply-To:References:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=WSx7DuhnCEqIedxRuxQ5y4ASknjDfVWYp60BVwiyUuc=; b=BF3LJgu7pe6XrdiOfn9tu9GaZ2yXkp3hxMvTl6qpt2sRGnYabOPrAV11ZlwMShd5eooJ Q0FCwGLmU0+WOh8Q6f/+iuqC9HDF5jpRy+gLeTJ9ge1fs/rSsExR0fTFLh/DDh+IvZ+D1 wr5r8pSjQtozorL/rFIjiznOyyStXGehWeWQ8MG1zHfhCM/oJ3QaTNgVn/QsKA6BlbUWv mjGWY7gsNNTXz4FCVLi1bnc08JLeIku2N4r3NVs8WFE3xA8uL3jl4BafNv+I5ZE/CzM2a VkyihufObWCgYY8lVusFBDpqdVEwq8z3Gw/wG15b8ANspjElY8VoWIAl5OAdxY5Pwnw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=atIYnbrZ; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CBC5D606A324 for ; Wed, 28 Oct 2026 20:00:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=atIYnbrZ Received: by smtp.kernel.org (Postfix) with ESMTPSA id 454881F01828; Wed, 28 Oct 2026 20:00:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793217644; bh=WSx7DuhnCEqIedxRuxQ5y4ASknjDfVWYp60BVwiyUuc=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=atIYnbrZ/qKLEKWeKs6EpfYPXgZ4AomqLhIc5EFxJ+ssiJMNPMZ9GxUddlkvOFQK7 3K2itjx+xPf2BCbvC6CbQEfap3RRCYoD6/35Qtbn9tjJIHM/S8aRy4ZlB819wU/zR4 Re4XoE0JrOuJf0s4OCNN0J78nl+bHr4Tpvg/fF/s4XfOCrkeQjHm4yRXKAL+Na3vWK XqjK3FQWXfh3GjdBpQoGnVRrDGmCaxFmvqNzF+sRCesvcBtnlTc0f5Bo1Doada07zS EEnfOKYllhqPhBxekyQmgc8B8DG+kMKZY3vd9WEKanHxRp60bFosN3ikRTlOqXIgLr awujI8hDXXYcw== Date: Wed, 28 Oct 2026 10:00:43 -1000 Message-ID: <66cdf745455b757dd236824902574430@kernel.org> From: Tejun Heo To: Jens Axboe Cc: Josef Bacik , linux-block@vger.kernel.org Subject: Re: [PATCH 34/98] block: don't enter reclaim under rq_qos_mutex In-Reply-To: <20261028164415.1262013-35-axboe@kernel.dk> References: <20261028164415.1262013-1-axboe@kernel.dk> <20261028164415.1262013-35-axboe@kernel.dk> X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit On Wed, Oct 28, 2026 at 10:41:37AM -0600, Jens Axboe wrote: > ioc_qos_write() and the wbt_lat_usec writers take rq_qos_mutex with the > queue frozen, blkcg_deactivate_policy() does the same with blkcg_mutex, > so nothing holding either may wait for IO. blkg_conf_prep() got > GFP_NOIO for the blkg in commit 5d726c4dbeed, but the > radix_tree_preload() right after it, the policy init functions and the > GFP_KERNEL fallback in blkcg_activate_policy() can still enter reclaim > there. lockdep reports the cycle on the first write to io.max. > > Use GFP_NOIO for all of them. > > Fixes: 9730763f4756 ("block: correct locking order for protecting blk-wbt parameters") > Fixes: 5d726c4dbeed ("blk-cgroup: fix possible deadlock while configuring policy") > Cc: Tejun Heo > Signed-off-by: Josef Bacik > Signed-off-by: Jens Axboe Acked-by: Tejun Heo Thanks. -- tejun