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 8CB8712C7FD for ; Wed, 7 Aug 2024 15:40:29 +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=1723045229; cv=none; b=UFoRDY1L6gIA5n18Yw6v89QmJfcugQ4Yy6tRzvx0+e74Eb5SCHnyBRq+MNXnY9O9Wb6a8tyxQ3cxvfx7iLjQVBfD4+WtQYbJ9lNGfQILR3fFf+n3bbO94ECtGDoRGGhWK0zUhtlNEPN7ViWrQnmQHvsYDXI7uOXTlLdIFCEc85U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723045229; c=relaxed/simple; bh=QM3/lOoqfsKEuqa3m+/xGfr7wd59Sfn09+GUDpqPrVY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=b98lc9fCbhL73Vi7FlXasYte7aQET+NjYmAsBbs74gfwqynd5QFlkuq4GjcUVKShZWeTknDKOHvSqaXihh0JuwFPBXZUpq+kkgrIfgpkTMze3RkZDrYf+Szr8UvaVYF6YQYvDYbD/KUSyGmITUdZMoxwqhZt1WPBqly7bvebU1M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SpMWWdpF; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SpMWWdpF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA10DC32781; Wed, 7 Aug 2024 15:40:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1723045229; bh=QM3/lOoqfsKEuqa3m+/xGfr7wd59Sfn09+GUDpqPrVY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=SpMWWdpFXvMlJacKkG8HcW/pWOH90zBItEZYhUishqGL5WwJnrucn1pLnEmNVp8BX 6cnrYrOcKmqtzGlp+u95z42MDW+0fp8MaI7LuYUOnLWDwS9UggTGnmvU8HZTt4g53U 8II/FcM8b4Y4QbDhwd6mRVrrmmtZB3IhKr5qDevBvexHAr0HuxPAVRgpE2Zdpuxcm8 CktXrnEnCIJHJZFLY0CUJO5hKyIOw6iA3go3QehTFhDvooil8c/nTlXChyA9GVCttd SWt2Lr6YENd3ui7eX2Oy3Qa2nPmfYYnnIu2BcIVabdzfcRBG1zT5hoO4HmgjNGU6CA JgcT6ZYknHfBw== Date: Wed, 7 Aug 2024 08:40:23 -0700 From: Keith Busch To: Keith Busch Cc: linux-pci@vger.kernel.org, bhelgaas@google.com, lukas@wunner.de, mika.westerberg@linux.intel.com Subject: Re: [PATCH RFC 0/8] pci: rescan/remove locking rework Message-ID: References: <20240722151936.1452299-1-kbusch@meta.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240722151936.1452299-1-kbusch@meta.com> On Mon, Jul 22, 2024 at 08:19:28AM -0700, Keith Busch wrote: > From: Keith Busch > > This patch set targets a subset of pci bus scanning and removals that > were shown to be problematic with deep pci topologies that support > native hotplug. I've tried to capture the common pci components, but > there are definitely many subsystems accessing the topology in their own > way, many of which I can't possibly test, and I have not tried to > convert every user to this new locking scheme. However, if I did this > correctly, they should be no worse off than today! > > The earlier patches are just cleanups and/or making it a little easier > to change the locking schemes. The real stuff happens from patches 7 and > 8. > > I've run this with lockdep enabled, tested concurrent hotplug events on > various x86 platforms with layers of pci switches. That said, as > mentioned earlier, there are many paths to here that I haven't been able > to test, so the final patch might be considered experimental. Any thoughts on this new scheme? I know I sent this during the merge window, so maybe bad timing on my part. Changing the locks like this is kind of scary too, so if that's the case, could we reconsider the band-aid patch from before? https://lore.kernel.org/linux-pci/20240612181625.3604512-2-kbusch@meta.com/