From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (Postfix) with ESMTP id A2FAA7F37 for ; Mon, 23 Nov 2015 14:26:37 -0600 (CST) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay3.corp.sgi.com (Postfix) with ESMTP id 33876AC002 for ; Mon, 23 Nov 2015 12:26:36 -0800 (PST) Received: from ipmail07.adl2.internode.on.net (ipmail07.adl2.internode.on.net [150.101.137.131]) by cuda.sgi.com with ESMTP id 9f4emtaorCBifFBH for ; Mon, 23 Nov 2015 12:26:33 -0800 (PST) Date: Tue, 24 Nov 2015 07:26:19 +1100 From: Dave Chinner Subject: Re: Does XFS support cgroup writeback limiting? Message-ID: <20151123202619.GE26718@dastard> References: <5652F311.7000406@5t9.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <5652F311.7000406@5t9.de> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Lutz Vieweg Cc: xfs@oss.sgi.com On Mon, Nov 23, 2015 at 12:05:53PM +0100, Lutz Vieweg wrote: > Hi, > > in June 2015 the article https://lwn.net/Articles/648292/ mentioned > upcoming support for limiting the quantity of buffered writes > using control groups. > > Back then, only ext4 was said to support that feature, with other > filesystems requiring some minor changes to do the same. Yes, changing the kernel code to support this functionality is about 3 lines of code. however.... > The generic cgroup writeback support made it into mainline > linux-4.2, I tried to find information on whether other filesystems > had meanwhile been adapted, but couldn't find this piece of information. > > Therefore I'd like to ask: Does XFS (as of linux-4.3 or linux-4.4) > support limiting the quantity of buffered writes using control groups? .... I haven't added support to XFS because I have no way of verifying the functionality works and that it continues to work as it is intended. i.e. we have no regression test coverage for cgroup aware writeback and until someone writes a set of regression tests that validate it's functionality works correctly it will remain this way. Writing code is trivial. Validating the code actually works as intended and doesn't silently get broken in the future is the hard part.... Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs