From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-181.mta0.migadu.com (out-181.mta0.migadu.com [91.218.175.181]) (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 3148D5336D for ; Wed, 12 Jun 2024 14:19:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718201963; cv=none; b=SYpmO+W1Oy+xQygdQJbAbcicxndHBDzr1Vj3OZJUDjv5yztWFV9XTwL4s8n0xFEteHqEpUixvRmSXG8A9Y6SKHP8ISGY6PmcJdcGPbdJ7QiYjbm5IWZyMN8eTvxpn31uh7MWUPMGbJtfTfDDn7KRbdfAA6VE/lYzP1Co673sHYQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718201963; c=relaxed/simple; bh=/onCZr4Z+weTYzmsfq1IIbhJMXw4FaLJ6Jn3ovKITuo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WvmWZEM7N2WD/HF7B/YWVpbl/wEGq6c3DBSPHyeaQzJNagjgmSs0O6s+a8WGbZXjBrNXVJFCoZFSGXSnmPSZoNovT7zCrHlSDNcaIhS7r7V1bUoWSwzw10eurcblIafGr2Dk4V7kJKkqmLe7FvPassy7L8BzEFkCQMt53cGlkbk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=JJzYQ8VM; arc=none smtp.client-ip=91.218.175.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="JJzYQ8VM" X-Envelope-To: bernd.schubert@fastmail.fm DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1718201954; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=1qyUcDw4VUGrxahyrz6XNaVMu1zSkDs4ZdYN1kGuIwo=; b=JJzYQ8VM1uLxaZ8wS525J/R7Wmkdn1+cRTDkMVo79K6uogeKOKwB023Pr3vijy4zwQBOJZ gd4a5hwhf5JxwWVmhMRHHFSPicshx6yd/7x0e1gUGn3Lyx7uxc1ktOVccS9O3OLtjQ/LWW abF7CwJ+l66FtnWCMWWlfej2vRAvduo= X-Envelope-To: miklos@szeredi.hu X-Envelope-To: bschubert@ddn.com X-Envelope-To: amir73il@gmail.com X-Envelope-To: linux-fsdevel@vger.kernel.org X-Envelope-To: akpm@linux-foundation.org X-Envelope-To: linux-mm@kvack.org X-Envelope-To: mingo@redhat.com X-Envelope-To: peterz@infradead.org X-Envelope-To: avagin@google.com X-Envelope-To: io-uring@vger.kernel.org Date: Wed, 12 Jun 2024 10:19:07 -0400 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Kent Overstreet To: Bernd Schubert Cc: Miklos Szeredi , Bernd Schubert , Amir Goldstein , linux-fsdevel@vger.kernel.org, Andrew Morton , linux-mm@kvack.org, Ingo Molnar , Peter Zijlstra , Andrei Vagin , io-uring@vger.kernel.org Subject: Re: [PATCH RFC v2 00/19] fuse: fuse-over-io-uring Message-ID: References: <20240529-fuse-uring-for-6-9-rfc2-out-v1-0-d149476b1d65@ddn.com> <99d13ae4-8250-4308-b86d-14abd1de2867@fastmail.fm> <62ecc4cf-97c8-43e6-84a1-72feddf07d29@fastmail.fm> 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=us-ascii Content-Disposition: inline In-Reply-To: X-Migadu-Flow: FLOW_OUT On Wed, Jun 12, 2024 at 03:53:42PM GMT, Bernd Schubert wrote: > I will definitely look at it this week. Although I don't like the idea > to have a new kthread. We already have an application thread and have > the fuse server thread, why do we need another one? Ok, I hadn't found the fuse server thread - that should be fine. > > > > The next thing I was going to look at is how you guys are using splice, > > we want to get away from that too. > > Well, Ming Lei is working on that for ublk_drv and I guess that new approach > could be adapted as well onto the current way of io-uring. > It _probably_ wouldn't work with IORING_OP_READV/IORING_OP_WRITEV. > > https://lore.gnuweeb.org/io-uring/20240511001214.173711-6-ming.lei@redhat.com/T/ > > > > > Brian was also saying the fuse virtio_fs code may be worth > > investigating, maybe that could be adapted? > > I need to check, but really, the majority of the new additions > is just to set up things, shutdown and to have sanity checks. > Request sending/completing to/from the ring is not that much new lines. What I'm wondering is how read/write requests are handled. Are the data payloads going in the same ringbuffer as the commands? That could work, if the ringbuffer is appropriately sized, but alignment is a an issue. We just looked up the device DMA requirements and with modern NVME only 4 byte alignment is required, but the block layer likely isn't set up to handle that. So - prearranged buffer? Or are you using splice to get pages that userspace has read into into the kernel pagecache?