ZFS random lockup

[AndCycle]

ok, I got another lockup again under heave i/o pressure,
I have crashed so many times in three days,

http://imgur.com/gallery/R0Ucqrw

sorry about using picture, I can't get anything work because the system is complete lockup that won't respond to magic key

here is the software ver.

Linux bacztwo 3.10.7-gentoo #9 SMP Fri Sep 6 01:11:05 CST 2013 x86_64 Intel(R) Core(TM) i7-2600S CPU @ 2.80GHz GenuineIntel GNU/Linux
sys-fs/zfs-0.6.2
sys-fs/zfs-kmod-0.6.2

No Forced Preemption

I am gonna try Voluntary Kernel Preemption this time

[AndCycle]

system survived this time,
the problem is gone after switch to Voluntary Kernel Preemption,

I thought this is related to #1682

[ryao]

Your backtrace shows that ZFS is waiting on a lock, but it does not really tell us much about why. This might have been caused by #1689.

[behlendorf]

Closing issue, moving to a kernel with ' Voluntary Kernel Preemption' enabled resolved this.