From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Mason Subject: Re: [PATCH V2] btrfs: implement delayed inode items operation Date: Fri, 18 Feb 2011 09:35:12 -0500 Message-ID: <1298039644-sup-69@think> References: <4D5CB6B8.2060804@cn.fujitsu.com> <1297991261-sup-6831@think> <4D5E36FC.2050401@cn.fujitsu.com> <1298031538-sup-7751@think> <4D5E6F88.1070005@cn.fujitsu.com> Content-Type: text/plain; charset=UTF-8 Cc: Linux Btrfs , Itaru Kitayama , Ito To: miaox Return-path: In-reply-to: <4D5E6F88.1070005@cn.fujitsu.com> List-ID: Excerpts from Miao Xie's message of 2011-02-18 08:09:28 -0500: > On fri, 18 Feb 2011 07:19:42 -0500, Chris Mason wrote: > > Excerpts from Miao Xie's message of 2011-02-18 04:08:12 -0500: > >> Hi, Chris > >> CC Tsutomu Itoh > >> > >> On Thu, 17 Feb 2011 20:09:00 -0500, Chris Mason wrote: > >>> Excerpts from Miao Xie's message of 2011-02-17 00:48:40 -0500: > >>>> Compare with Ext3/4, the performance of file creation and deletion on btrfs > >>>> is very poor. the reason is that btrfs must do a lot of b+ tree insertions, > >>>> such as inode item, directory name item, directory name index and so on. > >>>> > >>>> If we can do some delayed b+ tree insertion or deletion, we can improve the > >>>> performance, so we made this patch which implemented delayed directory name > >>>> index insertion/deletion and delayed inode update. > >>> > >>> This work is really cool, thanks for doing it. I'm starting a run on > >>> this tonight and if all goes well I'll review in detail and try to queue > >>> it along with the per-subvolume storage bits for .39. > >> > >> There is a hang-up problem in this patch, that is the task which does delayed item > >> balance and the task which commits the transaction will wait for each other, and > >> the filesystem will hang up. This is reported by Tsutomu Itoh. > >> > >> I have made the third version of this patch, will post it later. > > > > BUG: spinlock cpu recursion on CPU#2, btrfs-delayed-m/2762 > > lock: ffff88004f47bfb0, .magic: dead4ead, .owner: btrfs-delayed-m/2763, .owner_cpu: 2 > > Pid: 2762, comm: btrfs-delayed-m Not tainted 2.6.38-rc4-josef+ #209 > > Call Trace: > > [] ? spin_bug+0x9c/0xa3 > > [] ? do_raw_spin_lock+0x63/0x13c > > [] ? _raw_spin_lock+0xe/0x10 > > [] ? btrfs_try_spin_lock+0x2a/0x86 [btrfs] > > [] ? btrfs_search_slot+0x5dd/0x73d [btrfs] > > [] ? btrfs_lookup_inode+0x2f/0x91 [btrfs] > > [] ? mutex_lock+0x31/0x48 > > [] ? btrfs_update_delayed_inode+0x73/0x11e [btrfs] > > [] ? start_transaction+0x19f/0x1e3 [btrfs] > > [] ? btrfs_async_run_delayed_node_done+0xd6/0x180 [btrfs] > > [] ? process_timeout+0x0/0x10 > > [] ? worker_loop+0x17e/0x49f [btrfs] > > [] ? worker_loop+0x0/0x49f [btrfs] > > [] ? worker_loop+0x0/0x49f [btrfs] > > [] ? kthread+0x82/0x8a > > [] ? kernel_thread_helper+0x4/0x10 > > [] ? kthread+0x0/0x8a > > [] ? kernel_thread_helper+0x0/0x10 > > > > > > I hit this one overnight with spinlock debugging on. Is it the same > > problem you've fixed? > > I haven't hit this bug, could you tell me the reproduce steps? I just ran dbench 50. But I have spinlock debugging turned on (CONFIG_DEBUG_SPINLOCK). Looks like the patch probably forgot to unlock or release a path, I'll take a quick look. -chris