zfs recv hangs in kmem arena

[James R. Van Artsdalen]

On 10/16/2014 11:10 PM, Xin Li wrote:
> On 10/16/14 8:43 PM, James R. Van Artsdalen wrote:
> > On 10/16/2014 11:12 AM, Xin Li wrote:
> >>> On 9/26/2014 1:42 AM, James R. Van Artsdalen wrote:
> >>>> FreeBSD BLACKIE.housenet.jrv 10.1-BETA2 FreeBSD 10.1-BETA2
> >>>> #2 r272070M: Wed Sep 24 17:36:56 CDT 2014
> >>>> james at BLACKIE.housenet.jrv:/usr/obj/usr/src/sys/GENERIC
> >>>> amd64
> >>>>
> >>>> With current STABLE10 I am unable to replicate a ZFS pool
> >>>> using zfs send/recv without zfs hanging in state "kmem
> >>>> arena", within the first 4TB or so (of a 23TB Pool).
>
> >> What does procstat -kk 1176 (or the PID of your 'zfs' process
> >> that stuck in that state) say?
> >>
> >> Cheers,
> >>
> > SUPERTEX:/root# ps -lp 866 UID PID PPID CPU PRI NI   VSZ   RSS
> > MWCHAN   STAT TT      TIME COMMAND 0 866  863   0  52  0 66800
> > 29716 kmem are D+    1  57:40.82 zfs recv -duvF BIGTOX
> > SUPERTEX:/root# procstat -kk 866 PID    TID COMM             TDNAME
> > KSTACK 866 101573 zfs              -                mi_switch+0xe1
> > sleepq_wait+0x3a _cv_wait+0x16d vmem_xalloc+0x568 vmem_alloc+0x3d
> > kmem_malloc+0x33 keg_alloc_slab+0xcd keg_fetch_slab+0x151
> > zone_fetch_slab+0x7e zone_import+0x40 uma_zalloc_arg+0x34e
> > arc_get_data_buf+0x31a arc_buf_alloc+0xaa dmu_buf_will_fill+0x169
> > dmu_write+0xfc dmu_recv_stream+0xd40 zfs_ioc_recv+0x94e
> > zfsdev_ioctl+0x5ca
>
> Do you have any special tuning in your /boot/loader.conf?
>
> Cheers,
>
Below.  I had forgotten some of this was there.

After sending the previous message I ran kgdb to see if I could get a
backtrace with function args.  I didn't see how to do it for this proc,
but during all this the process un-blocked and started running again.

The process blocked again in kmem arena after a few minutes.


SUPERTEX:/root# cat /boot/loader.conf
zfs_load="YES"           # ZFS
vfs.root.mountfrom="zfs:SUPERTEX/UNIX"        # Specify root partition
in a way the
                # kernel understands
kern.maxfiles="32K"        # Set the sys. wide open files limit
kern.ktrace.request_pool="512"
#vfs.zfs.debug=1
vfs.zfs.check_hostid=0

loader_logo="beastie"        # Desired logo: fbsdbw, beastiebw, beastie,
none
boot_verbose="YES"        # -v: Causes extra debugging information to be
printed
geom_mirror_load="YES"        # RAID1 disk driver (see gmirror(8))
geom_label_load="YES"        # File system labels (see glabel(8))
ahci_load="YES"
siis_load="YES"
mvs_load="YES"
coretemp_load="YES"        # Intel Core CPU temperature monitor
#console="comconsole"
kern.msgbufsize="131072"    # Set size of kernel message buffer

kern.geom.label.gpt.enable=0
kern.geom.label.gptid.enable=0
kern.geom.label.disk_ident.enable=0
SUPERTEX:/root#