On Fri, 31 Aug 2012 13:40:16 +0800 gchen <gang.chen@xxxxxxxxxxx> wrote: > Hi linux-nfs@xxxxxxxxxxxxxxx > > I have 1 question, and also 2 conclusions which need confirm. > > > 1) Question: > > Jeff Layton said in Red Hat Bugzilla (bug 848706): > "Have configuration where the same host is acting as both NFS client > and server. That's a configuration known to cause deadlocks." > > Does it mean that the public Linux kernel (not Red Hat) also can cause > deadlocks if NFS client and server are under the same machine ? > Yes. > > 2) Confirm 1: (better by Jeff Layton) > > For function nfs_commit_set_lock in ./fs/nfs/write.c > > for latest public kernel version: > the parameters of out_of_line_wait_on_bit_lock() are > (&nfsi->flags, NFS_INO_COMMIT, nfs_wait_killable, TASK_KILLABLE) > for Red Hat kernel version: kernel-2.6.18-308.4.1.el5 > the parameters of out_of_line_wait_on_bit_lock() are > (&nfsi->flags, NFS_INO_COMMIT, > nfs_wait_bit_uninterruptible, TASK_UNINTERRUPTIBLE) > > It means for red hat version: > when deadlock occurs, we can not boot machine in normal way > (it is true for my test machine, the deadlock task can not be killed) > It means for public kernel version: > "Assume deadlock occurs", we can still boot machine in normal way, > because the task can be killed. > > Is what I said above correct ? > Not sure I understand your question. RHEL5 doesn't have support for TASK_KILLABLE, and I didn't backport it, hence the difference in that function. > > 3) Confirm 2: > > Is LTP (Linux Test Project) still a suitable test tools for public kernel ? > (for ltp-full-20100331.gz stress test, it mounts NFS on local machine, > and the latest LTP ltp-full-20120401.bz2 also seems the same). > That I'm not sure of. All I can tell you is that mounts over loopback (or similar configurations) are easily deadlockable under load. -- Jeff Layton <jlayton@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
