From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 008.lax.mailroute.net (008.lax.mailroute.net [199.89.1.11]) (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 A29EB7DA84; Thu, 17 Oct 2024 16:15:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=199.89.1.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729181745; cv=none; b=HYA6lVXDSMU5aLVVXkZAcFZHo9WEMQnD+RojwqhLS8oNt3gaJlfEiH4qCdP9CHJ/7ss2SrUJX/Rx3SrpeW+5pvQAuzqQeKZnurGaget/lQuZdpdePJnTBYIVh1rV8moaYKKZiMHVLGqPgA6X9ZKvDWEagaMQMdRi/dFoHmOWSEA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729181745; c=relaxed/simple; bh=zHcihhJxzUl73rzLdnTyPA7to6bVri5EKZRmag60bvA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=O88Ccu+PFTir69Q5WckBh8xhlnSlumdcpoqMwKMgjMqioQFnUQCYLz+w5x0wl9bczdo2laxAk/ue6GeQVqiVqVcKGt6Qh9pKyn5faMi3PWlE0f8mBycUb8hzQpCMU6YOm4Hf3/hE1Rg/yEVT/zPhpgO9Sl+u7CvnKbT4ygv4MSc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org; spf=pass smtp.mailfrom=acm.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b=Wchb2Z5X; arc=none smtp.client-ip=199.89.1.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=acm.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=acm.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=acm.org header.i=@acm.org header.b="Wchb2Z5X" Received: from localhost (localhost [127.0.0.1]) by 008.lax.mailroute.net (Postfix) with ESMTP id 4XTtH262R8z6ClY9q; Thu, 17 Oct 2024 16:15:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=acm.org; h= content-transfer-encoding:content-type:content-type:in-reply-to :from:from:content-language:references:subject:subject :user-agent:mime-version:date:date:message-id:received:received; s=mr01; t=1729181730; x=1731773731; bh=eOvuzv/ivWqYohoOrZsk5GZx XsPGRis/218uLdUYAGI=; b=Wchb2Z5XYlvD9yLHrkWMJ6WZ18gP6EzjpoiMon7w /ioP2BWSDakTfnlY9OKkoEjRyzCE2NOOA18+7w41OSCq0uXcSnxahdlv9J0aiPEW QgakT5aZFbr0akzCcs2YLtQ65bxWjFRd42Uw4sow2fAxYDW7xum2vunzfqAbpOdN wAvlVAszWgYMPxmJkBivBK0AyykLmVV2k+9Znv/0hwxsQlvsKVePSBGAyJBX01e+ QZS1/pTpqYT9bJvAKIITbijxh8ut7514vlLSZeturgZkOCEfwQroFlQvQC8d1wSb gsv59uKMu29HvZspqvF5XwKGHg8pluu4iD6ys3S5/VrpBA== X-Virus-Scanned: by MailRoute Received: from 008.lax.mailroute.net ([127.0.0.1]) by localhost (008.lax [127.0.0.1]) (mroute_mailscanner, port 10029) with LMTP id tuKOjPfACqLi; Thu, 17 Oct 2024 16:15:30 +0000 (UTC) Received: from [IPV6:2a00:79e0:2e14:8:c8b0:b4d2:d689:c93d] (unknown [104.135.204.81]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bvanassche@acm.org) by 008.lax.mailroute.net (Postfix) with ESMTPSA id 4XTtGj6bSlz6ClSqH; Thu, 17 Oct 2024 16:15:25 +0000 (UTC) Message-ID: <37af5088-6f09-4e75-b5d0-559e92d625bb@acm.org> Date: Thu, 17 Oct 2024 09:15:21 -0700 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 0/3] FDP and per-io hints To: Keith Busch , Christoph Hellwig Cc: Kanchan Joshi , axboe@kernel.dk, hare@suse.de, sagi@grimberg.me, martin.petersen@oracle.com, brauner@kernel.org, viro@zeniv.linux.org.uk, jack@suse.cz, jaegeuk@kernel.org, bcrl@kvack.org, dhowells@redhat.com, asml.silence@gmail.com, linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org, linux-block@vger.kernel.org, linux-aio@kvack.org, gost.dev@samsung.com, vishak.g@samsung.com, javier.gonz@samsung.com References: <20240930181305.17286-1-joshi.k@samsung.com> <20241015055006.GA18759@lst.de> <8be869a7-c858-459a-a34b-063bc81ce358@samsung.com> <20241017152336.GA25327@lst.de> Content-Language: en-US From: Bart Van Assche In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 10/17/24 8:44 AM, Keith Busch wrote: > On Thu, Oct 17, 2024 at 05:23:37PM +0200, Christoph Hellwig wrote: >> If you want to do useful stream separation you need to write data >> sequentially into the stream. Now with streams or FDP that does not >> actually imply sequentially in LBA space, but if you want the file >> system to not actually deal with fragmentation from hell, and be >> easily track what is grouped together you really want it sequentially >> in the LBA space as well. In other words, any kind of write placement >> needs to be intimately tied to the file system block allocator. > > I'm replying just to make sure I understand what you're saying: > > If we send per IO hints on a file, we could have interleaved hot and > cold pages at various offsets of that file, so the filesystem needs an > efficient way to allocate extents and track these so that it doesn't > interleave these in LBA space. I think that makes sense. > > We can add a fop_flags and block/fops.c can be the first one to turn it > on since that LBA access is entirely user driven. Does anyone care about buffered I/O to block devices? When using buffered I/O, the write_hint information from the inode is used and the per I/O write_hint information is ignored. Thanks, Bart.