From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:45124 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965742AbcKLCSa (ORCPT ); Fri, 11 Nov 2016 21:18:30 -0500 Date: Fri, 11 Nov 2016 18:18:22 -0800 From: Liu Bo To: Stefan Priebe - Profihost AG Cc: "linux-btrfs@vger.kernel.org" Subject: Re: spinning kworker with space_cache=v2 searching for free space Message-ID: <20161112021821.GC30930@dhcp-whq-twvpn-1-vpnpool-10-159-131-21.vpn.oracle.com> Reply-To: bo.li.liu@oracle.com References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Wed, Nov 09, 2016 at 09:19:21PM +0100, Stefan Priebe - Profihost AG wrote: > Hello, > > found this one from 2014: > https://patchwork.kernel.org/patch/5551651/ > > it this still valid? The space cache code doesn't change a lot, so I think the patch is still valid to apply(there might be some conflicts though), but I'm not sure if it could help the spinning case. Thanks, -liubo > > Am 09.11.2016 um 09:09 schrieb Stefan Priebe - Profihost AG: > > Dear list, > > > > even there's a lot of free space on my disk: > > > > # df -h /vmbackup/ > > Filesystem Size Used Avail Use% Mounted on > > /dev/mapper/stripe0-backup 37T 24T 13T 64% /backup > > > > # btrfs filesystem df /backup/ > > Data, single: total=23.75TiB, used=22.83TiB > > System, DUP: total=8.00MiB, used=3.94MiB > > Metadata, DUP: total=283.50GiB, used=105.82GiB > > GlobalReserve, single: total=512.00MiB, used=0.00B > > > > I always have a kworker process endless spinning. > > > > # perf top shows: > > 47,56% [kernel] [k] rb_next > > 7,71% [kernel] [k] tree_search_offset.isra.25 > > 6,44% [kernel] [k] btrfs_find_space_for_alloc > > > > Mount options: > > rw,noatime,compress-force=zlib,nossd,noacl,space_cache=v2,skip_balance > > > > What's wrong here? > > > > Greets, > > Stefan > >