From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2AB1117B418 for ; Fri, 4 Jul 2025 14:13:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751638432; cv=none; b=rxVQYLS3h0mTv6oTyDHK7qmh7Xs2jt26LLJQdXr/AKDKFru3e9MbFc+PsWOnyVsf891LSF+YNlj9rf6ED4pnFUdd13sxthK3LPHkPVY/GRRzv6/ZlHwxwqPnLP2S21dHDSW83j7OMB71EAS/gSYdo5AwwzgzfXq5QqzLre6HYQM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751638432; c=relaxed/simple; bh=XCXY0hdMPiwoxIy7NjLRfUW+PFoT6QLeCJ7ONYRjoLw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=EGEN7CFagyegyQsbs+ki87XzaBHYatKoFuk2WCceohaVtdq7IvPDViCOumcbQ0fYDOaHnh7HstrJX5mfhW4caetCHS6D9+m8oeSTFS19T5hD9QfbLJsudDNl8PDVEcgYQIPz7ZwWr1wB0vxCIIpkhjT1XQn2yM1oufQK0mmgu4o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=GWJ56djs; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="GWJ56djs" 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: 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 :)