From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Galbraith Subject: Re: 3.4.4-rt13: btrfs + xfstests 006 = BOOM.. and a bonus rt_mutex deadlock report for absolutely free! Date: Sat, 14 Jul 2012 15:38:16 +0200 Message-ID: <1342273096.7368.57.camel@marge.simpson.net> References: <1342072060.7338.102.camel@marge.simpson.net> <20120713125043.GH30128@shiny> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: "linux-rt-users@vger.kernel.org" , LKML , linux-fsdevel , Thomas Gleixner , Steven Rostedt To: Chris Mason Return-path: In-Reply-To: <20120713125043.GH30128@shiny> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org On Fri, 2012-07-13 at 08:50 -0400, Chris Mason wrote: > There is also a chunk of code in btrfs_clear_path_blocking that makes > sure to strictly honor top down locking order during the conversion. It > only does this when lockdep is enabled because in non-RT kernels we > don't need to worry about it. For RT we'll want to enable that as well. Hm, _seems_ that alone is enough prevent deadlock. Throughput really sucks though. The other bits of my stab bump throughput for dbench 128 from ~200 mb/s to ~360 mb/s (appears it's the paranoid trylock loops). ext3 does 775 mb/s with the same kernel. Or, dbench 8 on ext3 gives ~1800 mb/s and ~480 mb/s btrfs. Not exactly wonderful. Hohum, guess I'll wait and see what your patch looks like. I bet it'll work a lot better than mine does :) -Mike