From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Guertin Subject: Re: Applications using fsync cause hangs for several seconds every few minutes Date: Wed, 17 Aug 2011 10:24:12 -0400 Message-ID: <4E4BCF0C.7060109@uvm.edu> References: <4E41A6A4.9070702@uvm.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 To: linux-btrfs@vger.kernel.org Return-path: In-Reply-To: <4E41A6A4.9070702@uvm.edu> List-ID: On 08/09/2011 05:29 PM, Andrew Guertin wrote: > On 06/21/2011 01:15 PM, Jan Stilow wrote: >> Hello, >> >> Nirbheek Chauhan gentoo.org> writes: >>> [...] >>> >>> Every few minutes, (I guess) when applications do fsync (firefox, >>> xchat, vim, etc), all applications that use fsync() hang for several >>> seconds, and applications that use general IO suffer extreme >>> slowdowns. iotop shows various combinations of the processes listed >>> below doing writes, and the total write as 2-3MB/s. >>> >>> [btrfs-dealloc-] >>> [btrfs-submit-0] >>> [btrfs-transacti] >>> [btrfs-endio-wri] >>> [flush-btrfs-1] >> >> I'm using btrfs under a 2.6.39-ARCH kernel and run into the same issue. >> >> In my case the [btrfs-submit-0] and [btrfs-transacti] shows up in iotop >> and produce 99% of IO at the time a application is frozen. For something >> like 10 to 30 seconds. >> >> [...] > > I see the same issue. I have bisected it to > > 4e69b598f6cfb0940b75abf7e179d6020e94ad1e is the first bad commit > commit 4e69b598f6cfb0940b75abf7e179d6020e94ad1e > Author: Josef Bacik > Date: Mon Mar 21 10:11:24 2011 -0400 > > Btrfs: cleanup how we setup free space clusters > > ...which came in between 2.6.38 and 2.6.39. Any chance of someone looking at this? I (and presumably others) haven't been able to upgrade my kernel past 2.6.38 because of this. --Andrew