On Sat, Feb 11, 2006 at 06:38:03PM +0100, Tomas M wrote: > When I use unionfs in my Linux notebook, everything is OK. But when I > use the same unionfs.ko module on the P4 machine (with the same > kernel), it causes many SEGFAULTs etc.
What does dmesg say? > Then it works flawlessly. Maybe it's only a bug in Linux kernel ACPI > or SMP code, ACPI is notorious for being mis-implemented by the hardware manufacturers, kernel developers can't really do anything about that, except blacklist the worst cases, and work around the better ones. > nevertheless I would like to ask a general question: Is > it any special case of usage to run unionsf on multiprocessor > machines? In other words, do you, developers, think about > multiprocessor configuration while developing unionfs? Is there any > difference? I, personally, try to think about concurency issues whenever I can. As you may have noticed unionfs code wasn't always written with it in mind (for example, branch management is currently quite racy.) This, I think, is because UnionFS was developed very quickly on single processor systems running 2.4 kernels (which do not have preemption.) 2.6's preemption, and now the easy access to "SMP" systems is making many kernel bugs appear seemingly out of nowhere. Bugs which for long time sat in the code, waiting for the right sequence of circumstances to occur. > Basically I don't depend on the answer, just would like to bring this > to your attention. Thank you. I'm sure that once we submit the code for review for eventual inclusion into vanilla kernel, we'll get plenty of comments about locking :) Jeff. _______________________________________________ unionfs mailing list [email protected] http://www.fsl.cs.sunysb.edu/mailman/listinfo/unionfs
