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 6830D31618B; Fri, 14 Nov 2025 11:47:31 +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=1763120851; cv=none; b=MbDKiIIThg6TFWSALCSgLusnviEubfjMZpUYmk7vDjw3L2w5VjUPs9VYRUcBjiQshnDxmOCW5iAyhEPFCC1eI1uyAa2aPyztiCfJgulqPTxtjG/UYc8m9YJ7Y73XdMeIMzQgscTY4XK2qwgO3duV9FtiRo+MqvnPO3HFW3QQHTs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763120851; c=relaxed/simple; bh=RYmfyxnd44YBm9qRxknxIsvpnN+q7uX4ZyGg3dXJhWs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=X3jb5ilBryEVy9CDe9N5KvFlwgJjzKoT5xP1RTZ5aBNByGZ0U8We0gKXweSOxkZMwTy9KdLZDw2dvUie4f3eZZoWynvKXKj1WNWSRATWls1G3evnbxiOpV1dWO60TgsfBaFT+HxnJlqw9IOV8NN5fBeW+5G1fHhhQKWJzDRyggE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=swCOEUwF; 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="swCOEUwF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA0E5C16AAE; Fri, 14 Nov 2025 11:47:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763120850; bh=RYmfyxnd44YBm9qRxknxIsvpnN+q7uX4ZyGg3dXJhWs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=swCOEUwFDZh8N+CoqAHwqJnNTs9ArbLrXSHUkfNMxzE0dAsJhXF1YK0h4dinnNmnh AxVxjv5ZiMIo4scYa777S1WkauAAN9o2XKahy9hEbqn/U2842NbuRuc5I6XW6dqlqA js/BsvNShGpxDkicSX8r01+7sPT2FuMggxoJjoYPJ67bQZ8mPA914Zoz5kZQm+JBlr AlPBH7CQ4rI4BXLRjmBRToIydgTB2iVCEgK6lGYWeRIqcetLLIjk8J/JU6oJ/4pqJj EGXUjf2huxpfz9kJQt2bM1LOJjtnPvGO//3QQwl+NRSuQ3elsMJow5RcDmNUzEqbeT kfRsAo79aRA1Q== From: Christian Brauner To: Christoph Hellwig Cc: Christian Brauner , Alexander Viro , "Darrick J. Wong" , Jan Kara , Jens Axboe , Avi Kivity , Damien Le Moal , Naohiro Aota , Johannes Thumshirn , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org Subject: Re: enable iomap dio write completions from interrupt context v2 Date: Fri, 14 Nov 2025 12:47:23 +0100 Message-ID: <20251114-postfach-entgleisen-90917e292b3b@brauner> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251113170633.1453259-1-hch@lst.de> References: <20251113170633.1453259-1-hch@lst.de> Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" X-Developer-Signature: v=1; a=openpgp-sha256; l=1669; i=brauner@kernel.org; h=from:subject:message-id; bh=RYmfyxnd44YBm9qRxknxIsvpnN+q7uX4ZyGg3dXJhWs=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWSKi50R1z5mnR649NWxqalN2uIdtnbppw8FT7raXLQk9 w5HV3t4RykLgxgXg6yYIotDu0m43HKeis1GmRowc1iZQIYwcHEKwEQYEhj+Z65YkBj3kLsuZgWb 5ZumxbsTSq58lD8XN8lo9s1pn+8IcjEyrJ1yW/njkUn8TOtexN3lKy0SN9wrE/wowcDz2E92xnm TeQA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Content-Transfer-Encoding: 8bit On Thu, 13 Nov 2025 18:06:25 +0100, Christoph Hellwig wrote: > Currently iomap defers all write completions to interrupt context. This > was based on my assumption that no one cares about the latency of those > to simplify the code vs the old direct-io.c. It turns out someone cared, > as Avi reported a lot of context switches with ScyllaDB, which at least > in older kernels with workqueue scheduling issues caused really high > tail latencies. > > [...] Applied to the vfs-6.19.iomap branch of the vfs/vfs.git tree. Patches in the vfs-6.19.iomap branch should appear in linux-next soon. Please report any outstanding bugs that were missed during review in a new review to the original patch series allowing us to drop it. It's encouraged to provide Acked-bys and Reviewed-bys even though the patch has now been applied. If possible patch trailers will be updated. Note that commit hashes shown below are subject to change due to rebase, trailer updates or similar. If in doubt, please check the listed branch. tree: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git branch: vfs-6.19.iomap [1/5] fs, iomap: remove IOCB_DIO_CALLER_COMP https://git.kernel.org/vfs/vfs/c/56749ed317e2 [2/5] iomap: always run error completions in user context https://git.kernel.org/vfs/vfs/c/222f2c7c6d14 [3/5] iomap: rework REQ_FUA selection https://git.kernel.org/vfs/vfs/c/845c50436431 [4/5] iomap: support write completions from interrupt context https://git.kernel.org/vfs/vfs/c/a4ae47e5d2bc [5/5] iomap: invert the polarity of IOMAP_DIO_INLINE_COMP https://git.kernel.org/vfs/vfs/c/65a466aef147