On Mon, 12 Dec 2011 06:43:45 +0800 Barry Kauler <[email protected]> wrote:
> On 12/7/11, Thomas Himmelmann <[email protected]> wrote: > > > Unionfs 2.5.10 don't work stable on kernel 3.0 and 3.1 for me. > > 2.5.10 is rock-solid with a 3.0.7 kernel for me. > > There is something that I found out about the Linux kernel, that might > affect the stability of Unionfs... > > A little while ago, we found that one of these config option makes > operation unreliable: > > CONFIG_SCHED_SMT > SMT scheduler support improves the CPU scheduler's decision making > when dealing with Intel Pentium 4 chips with HyperThreading at a cost > of slightly increased overhead in some places. If unsure say N here. > > CONFIG_SCHED_MC > Multi-core scheduler support improves the CPU scheduler's decision > making when dealing with multi-core CPU chips at a cost of slightly > increased overhead in some places. If unsure say N here. > > We were getting mysterious errors when using the 'cp' command. When > copying a complete directory hierarchy, some files/directories were > sometimes completely missing from the destination. There were no error > messages. This has nothing to do with Unionfs (these errors were > occurring in ext2/3 partitions outside of any layer filesystem), I am > describing a fundamental flakyness of the kernel, not just the 3.x, > earlier too. > > I discovered that turning off CONFIG_SCHED_SMT and CONFIG_SCHED_MC > fixed it. It is probably only one of those that is the culprit though, > probably CONFIG_SCHED_MC, but I never verified that. > > So, my kernel has: > > CONFIG_SMP=y > # CONFIG_SCHED_SMT is not set > # CONFIG_SCHED_MC is not set > > I recommend, configure your kernel the same, then see if you still get > the problems with Unionfs 2.5.10. If those fixed your problems, then it means locking is borked. I.e not a scheduler problem. What kind of device driver? Could be bad disk controller driver. Did you report it to distro or kernel mailing list? _______________________________________________ unionfs mailing list: http://unionfs.filesystems.org/ [email protected] http://www.fsl.cs.sunysb.edu/mailman/listinfo/unionfs
