[Gluster-users] Thread-safety of glfs_init

Poornima Gurusiddaiah pgurusid at redhat.com
Tue Jul 8 13:37:34 UTC 2014


Hi,

Accessing the same volume via different threads using gfapi should work fine.

The crash you seem to be hitting, may be because of the mismatch in the version
of libgfapi Quemu was built and the libgfapi currently present on the system. Check
the same, if that doesn't seem to be an issue please report a bug with more log data.

[2] can be be reproduced only if the same process is opening multiple volumes(gfapi_new) and closing.
If the process dies all the resources are cleaned and hence not an issue.

Regards,
Poornima


----- Original Message -----
From: "Tiziano Müller" <tiziano.mueller at stepping-stone.ch>
To: gluster-users at gluster.org
Sent: Friday, July 4, 2014 12:57:26 PM
Subject: [Gluster-users] Thread-safety of glfs_init

Hi there

I am currently trying to benchmark and test glusterfs resp. the gfapi and use
fio for that. I would especially like a way to reproduce [1] and [2] properly.

When using processes, the tests work, but the OS will then cleanup threads and
memory, so reproducing [2] is not possible.

When starting fio with --thread (and --stonewall) as described in [3] I get the
following error:

Starting 8 threads
[2014-07-04 05:28:46.997537] E [mem-pool.c:349:mem_get0]
(-->/usr/lib64/libgfapi.so.0(glfs_init+0x9) [0x7fa68b521369]
(-->/usr/lib64/libgfapi.so.0(glfs_init_common+0x93) [0x7fa68b521223]
(-->/usr/lib64/libglusterfs.so.0(get_new_dict_full+0x25) [0x7fa689d9cbe5])))
0-mem-pool: invalid argument
glfs_init failed. Is glusterd running on brick?

Please also note that one must use latest fio HEAD since there was another bug I
fixed causing fio to segfault if opening a file using gfapi was unsuccessful.

The above tests are with glusterfs-3.4.5-beta1.

Any ideas? Is gfapi and accessing the same volume via different threads in
particular considered to be safe? (see glusterfs.c in [4] on how fio does it)

Thanks,
Tiziano

[1] https://bugs.launchpad.net/qemu/+bug/1333651
[2] https://bugzilla.redhat.com/show_bug.cgi?id=1093594
[3] http://wiki.stoney-cloud.org/index.php/GlusterFS_Benchmark
[4] http://git.kernel.dk/?p=fio.git;a=tree;f=engines;hb=HEAD

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