> -----Original Message----- > From: Chris Mason [mailto:clm@xxxxxx] > Sent: Thursday, January 21, 2016 1:48 AM > To: Zhao Lei <zhaolei@xxxxxxxxxxxxxx>; linux-btrfs@xxxxxxxxxxxxxxx > Subject: Re: [PATCH 1/2] btrfs: reada: limit max works count > > On Wed, Jan 20, 2016 at 10:16:27AM -0500, Chris Mason wrote: > > On Tue, Jan 12, 2016 at 03:46:26PM +0800, Zhao Lei wrote: > > > reada create 2 works for each level of tree in recursion. > > > > > > In case of a tree having many levels, the number of created works is > > > 2^level_of_tree. > > > Actually we don't need so many works in parallel, this patch limit > > > max works to BTRFS_MAX_MIRRORS * 2. > > > > Hi, > > > > I don't think you end up calling atomic_dec() for every time that > > reada_start_machine() is called. Also, I'd rather not have a global > > static variable to limit the parallel workers, when we have more than > > one FS mounted it'll end up limiting things too much. > > > > With this patch applied, I'm seeing deadlocks during btrfs/066. You > > have to run the scrub tests as well, basically we're just getting > > fsstress run alongside scrub. > > > > I'll run a few more times with it reverted to make sure, but I think > > it's the root cause. > > I spoke too soon, it ended up deadlocking a few tests later. Sorry for now I'm > pulling all the reada patches. We'll sort out bug fixes vs cleanups in later rcs. > > With all of the reada patches removed, the deadlocks are gone. > Sorry for hear it. Actually I run xfstests with all patch applied, and see no regression in my env: FSTYP -- btrfs PLATFORM -- Linux/x86_64 lenovo 4.4.0-rc6_HEAD_8e16378041f7f3531c256fd3e17a36a4fca92d29_+ MKFS_OPTIONS -- /dev/sdb6 MOUNT_OPTIONS -- /dev/sdb6 /var/ltf/tester/scratch_mnt btrfs/066 151s ... 164s Ran: btrfs/066 Passed all 1 tests I'll investigate the root reason. Thanks Zhaolei > -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
