Daniel Lezcano daniel.lezc...@free.fr writes:
On 01/12/2011 07:39 AM, Trent W. Buck wrote:
Mikedeb...@good-with-numbers.com writes:
Trent W. Buck wrote:
I can provision a new LXC container, which includes running a few
aptitude install foo lines (inside the containers), and it Just Works.
If I try to provision two containers at the same time, both containers
appear to hang with a dpkg process in the D state[0].
My config for each container looks like this:
lxc.mount.entry = /home /srv/lxc/proud/home none bind
Doesn't aptitude write into the home directory that you're sharing
across containers? locks ~/.aptitude/cache?
Possibly, but dhclient's running aptitude as uid 0, whose home is in
/root, which is not shared between hosts.
In any case, IIRC I export HOME=`mktemp -d` before aptitude runs, as a
fugly workaround for etckeeper.
I suppose if containers' /tmp are tmpfses, aptitude might be running
into some problem with locking on tmpfs, although I'm not aware of any
bogus operational semantics for tmpfs...
Can you give, for each process in D state, the content of
/proc/pid/stack ?
That may help to understand where the lock occurs in the kernel
I ran into it again today, accidentally.
I was recently reminded that dpkg doesn't mix well with ext4 and btrfs,
because it calls sync/fsync all the time. Now, my containers are on
different ext4 LVs, but maybe 1 process calling f/sync all the time is
enough to slow them both down.
I'm being a bit more patient than last time, and I think they ARE
proceeding, just REALLY slowly. Meanwhile aptitude consumes a 100% of a
core busy-waiting for a response from dpkg :-/
They look like this:
$ ssh omega cat /proc/7713/stack
Warning: Permanently added 'omega,192.168.155.22' (RSA) to the list of
known hosts.
[811669b7] sync_inodes_sb+0x87/0xb0
[8116b292] __sync_filesystem+0x82/0x90
[8116b379] sync_filesystems+0xd9/0x130
[8116b431] sys_sync+0x21/0x40
[810121b2] system_call_fastpath+0x16/0x1b
[] 0x
$ ssh omega cat /proc/5619/stack
Warning: Permanently added 'omega,192.168.155.22' (RSA) to the list of
known hosts.
[81222865] jbd2_log_wait_commit+0xc5/0x150
[811d7a2c] ext4_sync_file+0x13c/0x2e0
[8116b051] vfs_fsync_range+0xa1/0xe0
[8116b0fd] vfs_fsync+0x1d/0x20
[8116b13e] do_fsync+0x3e/0x60
[8116b190] sys_fsync+0x10/0x20
[810121b2] system_call_fastpath+0x16/0x1b
[] 0x
I couldn't capture 1 pid from the same ps run before one or the other
vanished. The ps output of D states looks like this:
$ ssh omega lxc-ps auxf | grep ' D '
root 465 0.0 0.0 0 0 ?DJan12 0:04
\_ [kdmflush]
root 476 0.0 0.0 0 0 ?DJan12 0:01
\_ [kdmflush]
root 591 0.0 0.0 0 0 ?DJan12 0:10
\_ [jbd2/dm-0-8]
root 1437 0.0 0.0 0 0 ?DJan12 0:11
\_ [jbd2/dm-3-8]
root 2278 0.0 0.0 0 0 ?DJan12 0:21
\_ [kdmflush]
root 2293 0.0 0.0 0 0 ?DJan12 1:06
\_ [jbd2/dm-21-8]
root 26611 0.0 0.0 0 0 ?D15:27 0:00
\_ [kdmflush]
root 26635 0.0 0.0 0 0 ?D15:27 0:00
\_ [jbd2/dm-6-8]
template-amd64 root 4763 0.7 0.0 17708 6064 ?D15:47
0:00 | | \_ /usr/bin/dpkg --status-fd 34
--unpack --auto-deconfigure
/srv/mirror/ubuntu/pool/main/u/udev/udev_151-12.3_amd64.deb
/srv/mirror/ubuntu/pool/main/l/lvm2/dmsetup_1.02.39-1ubuntu4.1_amd64.deb
/srv/mirror/ubuntu/pool/main/g/glib2.0/libglib2.0-0_2.24.1-0ubuntu1_amd64.deb
/srv/mirror/ubuntu/pool/main/libu/libusb/libusb-0.1-4_0.1.12-14ubuntu0.2_amd64.deb
/srv/mirror/ubuntu/pool/main/p/plymouth/plymouth_0.8.2-2ubuntu2.2_amd64.deb
/srv/mirror/ubuntu/pool/main/libp/libpng/libpng12-0_1.2.42-1ubuntu2.1_amd64.deb
/srv/mirror/ubuntu/pool/main/p/plymouth/libplymouth2_0.8.2-2ubuntu2.2_amd64.deb
/srv/mirror/ubuntu/pool/main/m/mountall/mountall_2.15.3_amd64.deb
/srv/mirror/ubuntu/pool/main/u/upstart/upstart_0.6.5-8_amd64.deb
/srv/mirror/ubuntu/pool/main/u/util-linux/bsdutils_2.17.2-0ubuntu1.10.04.2_amd64.deb
greed root 4325 0.7 0.1 14296 8880 ?D15:45 0:01
| \_ /usr/bin/dpkg --status-fd 35 --unpack
--auto-deconfigure
/srv/mirror/ubuntu/pool/main/x/xorg/x11-common_7.5+5ubuntu1_all.deb
/srv/mirror/ubuntu/pool/main/f/freetype/libfreetype6_2.3.11-1ubuntu2.4_amd64.deb
/srv/mirror/ubuntu/pool/main/t/ttf-dejavu/ttf-dejavu-core_2.30-2_all.deb
/srv/mirror/ubuntu/pool/main/f/fontconfig/fontconfig-config_2.8.0-2ubuntu1_all.deb
