On 09/07/2010 12:35 PM, Tejun Heo wrote: > Can you please help me a bit more? Are you saying the following? > > Work w0 starts execution on wq0. w0 tries locking but fails. Does > delay(1) and requeues itself on wq0 hoping another work w1 would be > queued on wq0 which will release the lock. The requeueing should make > w0 queued and executed after w1, but instead w1 never gets executed > while w0 hogs the CPU constantly by re-executing itself. Also, how > does delay(1) help with chewing up CPU? Are you talking about > avoiding constant lock/unlock ops starving other lockers? In such > case, wouldn't cpu_relax() make more sense? Ooh, almost forgot. There was nr_active underflow bug in workqueue code which could lead to malfunctioning max_active regulation and problems during queue freezing, so you could be hitting that too. I sent out pull request some time ago but hasn't been pulled into mainline yet. Can you please pull from the following branch and add WQ_HIGHPRI as discussed before and see whether the problem is still reproducible? And if the problem is reproducible, can you please trigger sysrq thread dump and attach it? git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-linus Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
