-----Original Message----- From: xfs-bounces@xxxxxxxxxxx [mailto:xfs-bounces@xxxxxxxxxxx] On Behalf Of Dave Chinner Sent: Tuesday, February 12, 2013 9:16 PM To: Cheung, Norman Cc: 'linux-xfs@xxxxxxxxxxx' Subject: Re: Hung in D state during fclose On Wed, Feb 13, 2013 at 12:12:47AM +0000, Cheung, Norman wrote: > Dave, > > One other point I have forgotten to mention is that the parent thread > will wait for 5 minutes and then lower the thread priority (from -2 > back to 20) and set a global variable to signal the threads to exit. > The blocked thread responded well and exit from D state and fclose > completed with no error. So it's not hung - it's just very slow? [NLC] It will pause forever. I tried replaced the timeout with a sleep loop, and it will pause forever. That is how I got the stack trace. You have 256GB of memory. It's entirely possible that you've dirtied a large amount of memory and everything is simply stuck waiting for writeback to occur. Perhaps you should have a look at the utilisation of your disks when this still occurs. 'iostat -x -d -m 5' will give you some insight into utilsation when a hang occurs... [NLC] I have set the dirty_background_bytes to 40M and dirty_writeback_centisecs to 400; and watched the Meminfo. I don't get a lot of dirtied memory accumulation -- 7 to 10 M average. The disk usage from the sar log was steady at 150M/sec for each of the disk; but a few seconds after the fclose all disk activities stopped. Also the CPU % was quiet as well. > This cause me to wonder if it is possible that some XFS threads and > my application thread might be in a deadlock. Deadlocks are permanent, so what you are seeing is not a deadlock.... [NLC] Would it be possible that there is priority inversion between my disk writing threads and the XFS threads & flush threads? My application thread runs at -2 priority. Many thanks, Norman Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
