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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 83524C83F03 for ; Fri, 4 Jul 2025 14:30:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type: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=FlQPn2sHWp1k8A+kShoH+cl9CqxTXVfmDisf36mJ3PM=; b=ABAM9TL0Up1QQbhcwFhzul2V4q qIhUSCtGF7zJGR+qGYgsHfRLw99RuhkundjNSZMZ0RoUBMu0BnGFgzi33n0sUGvpYpXZzTF+EA/U+ krpGdSOfjrKC/SN2OVqu6HMEUUYe9jQxpCMjow5/xZZzuNwA6EYK9rhlLglx0BCX1IwUREymG00KI AG1W2fQZEVI9DK/1Ni843ShL87GJ0gcSGWWYq16fm8Sn9hKunuzYzYjPkGF5z53PNW6wGegQHAq1x hzo2Nqo/KcZcl0nKcwdMRCIcfBmQutbbX+RSdmyof8/5MWpbVFpQ0QyPkjTzJJYpU9hnmt1ypFGk9 btqBJr8w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uXhRC-0000000EfuJ-18mV; Fri, 04 Jul 2025 14:30:50 +0000 Received: from nyc.source.kernel.org ([2604:1380:45d1:ec00::3]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uXhAm-0000000EdOR-3NL0 for linux-nvme@lists.infradead.org; Fri, 04 Jul 2025 14:13:53 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id E0F2BA53C68; Fri, 4 Jul 2025 14:13:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3511C4CEE3; Fri, 4 Jul 2025 14:13:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1751638431; bh=XCXY0hdMPiwoxIy7NjLRfUW+PFoT6QLeCJ7ONYRjoLw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GWJ56djs5EVcj5vZ0V8Lid01iehqE4UQEL5JLbMyTCobCze7PGMhuP0Zc24FK1XF1 S86BpFCcsYgd1e8ikKo7WyZ1vb9HIN6PK/rDR0zj5NJECBgjZHmfWYht2FlyLk4LW3 KrpM4hGGL/P799y92Xd4Zuq8YUMDj/ag5FdWlZ9k= Date: Fri, 4 Jul 2025 16:13:48 +0200 From: Greg Kroah-Hartman To: David Jeffery Cc: Christoph Hellwig , Stuart Hayes , linux-kernel@vger.kernel.org, "Rafael J . Wysocki" , Martin Belanger , Oliver O'Halloran , Daniel Wagner , Keith Busch , Lukas Wunner , Jeremy Allison , Jens Axboe , Sagi Grimberg , linux-nvme@lists.infradead.org, Nathan Chancellor , Jan Kiszka , Bert Karwatzki Subject: Re: [PATCH v10 0/5] shut down devices asynchronously Message-ID: <2025070438-apache-sprawl-0cbc@gregkh> References: <20250625201853.84062-1-stuart.w.hayes@gmail.com> <20250703114656.GE17686@lst.de> <2025070408-starlight-pandemic-0266@gregkh> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250704_071352_905574_4D772528 X-CRM114-Status: GOOD ( 23.17 ) 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: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Fri, Jul 04, 2025 at 10:09:01AM -0400, David Jeffery wrote: > On Fri, Jul 4, 2025 at 9:45 AM Greg Kroah-Hartman > wrote: > > > > On Fri, Jul 04, 2025 at 09:38:15AM -0400, David Jeffery wrote: > > > On Thu, Jul 3, 2025 at 7:47 AM Christoph Hellwig wrote: > > > > > > > > On Wed, Jun 25, 2025 at 03:18:48PM -0500, Stuart Hayes wrote: > > > > > Address resource and timing issues when spawning a unique async thread > > > > > for every device during shutdown: > > > > > * Make the asynchronous threads able to shut down multiple devices, > > > > > instead of spawning a unique thread for every device. > > > > > * Modify core kernel async code with a custom wake function so it > > > > > doesn't wake up threads waiting to synchronize every time the cookie > > > > > changes > > > > > > > > Given all these thread spawning issues, why can't we just go back > > > > to the approach that kicks off shutdown asynchronously and then waits > > > > for it without spawning all these threads? > > > > > > > > > > The async subsystem fix is something that should be fixed regardless > > > of async shutdown. Async shutdown's use just exposed its thundering > > > herd behavior which is easily fixed. > > > > Great, then please submit that on its own and get the maintainer of that > > subsystem to agree and accept it as I have no way to judge that code at > > all. > > Unfortunately, it does not have a maintainer listed and sees limited > activity. Would CC-ing some of the recent developers of kernel/async.c > to ask them to review be recommended in this situation? Like any other piece of the kernel, yes :)