From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boaz Harrosh Subject: Re: [PATCH v2] Support for write stream IDs Date: Wed, 06 May 2015 19:50:48 +0300 Message-ID: <554A4668.7040804@plexistor.com> References: <1430856181-19568-1-git-send-email-axboe@fb.com> <55493097.6040007@fb.com> <55493AC1.9090408@fb.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: Jeff Moyer , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, adilger@dilger.ca, david@fromorbit.com To: "Martin K. Petersen" , Jens Axboe Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On 05/06/2015 01:09 AM, Martin K. Petersen wrote: >>>>>> "Jens" == Jens Axboe writes: <> > > The only sensible solution is for the kernel to manage the stream > IDs. And for them to be plentiful. The storage device is free to ignore > them, do LRU or whatever it pleases to manage them if it has an internal > limit on number of open streams, etc. > Sometimes you do not have control over the "storage device" firmware and/or it is already too late. But in such a case the LLD of the device can do the state management (open/close) and translation (LRU). If there are a lot of broken devices with the same small size that need an LRU and/or state, bunch of LLDs can reuse a common library. But hey yes I'm with Martin here. It sounds like a filesystem thing and not an application thing. >>From the application side we already have the O_TMP hint and other fadvise hits, but it is more the filesystem policy of what to do with this. Also current proposed solution for application is kind of a layering violation. I set an Id at the filesystem level API: Open a file, set an ID. But I acquire the ID from the block device under the FS. This will never map well. In fact it calls for only a very hard-coded hardware specific application that can use this. Thanks Boaz