From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cloud1-vm154.de-nserver.de ([178.250.10.56]:29184 "EHLO cloud1-vm154.de-nserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750775AbcKLH6l (ORCPT ); Sat, 12 Nov 2016 02:58:41 -0500 Subject: Re: spinning kworker with space_cache=v2 searching for free space To: bo.li.liu@oracle.com References: <20161112021821.GC30930@dhcp-whq-twvpn-1-vpnpool-10-159-131-21.vpn.oracle.com> Cc: "linux-btrfs@vger.kernel.org" From: Stefan Priebe - Profihost AG Message-ID: Date: Sat, 12 Nov 2016 08:58:31 +0100 MIME-Version: 1.0 In-Reply-To: <20161112021821.GC30930@dhcp-whq-twvpn-1-vpnpool-10-159-131-21.vpn.oracle.com> Content-Type: text/plain; charset=windows-1252 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Am 12.11.2016 um 03:18 schrieb Liu Bo: > 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 got it applied and will try it. Any other ideas why it's pinning there? Free space fragmentation? But at least on one machine there are 26TB free and it's spinning... slowing down the performance. Greets, Stefan > > 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 >>>