Tejun Heo <htejun@xxxxxxxxx> wrote: > Elias Oltmanns wrote: >> Tejun Heo <htejun@xxxxxxxxx> wrote: >>> Elias Oltmanns wrote: >>>> This proves that piix_qc_defer() has declined the same command 100 >>>> times in succession. However, this will only happen if the status of >>>> all the commands enqueued for one port hasn't changed in the >>>> meantime. This suggests to me that the threads scheduled for command >>>> execution and completion aren't served for some reason. Any ideas? >>> Blocked counts of 1 will cause busy looping because when blk_run_queue() >>> returns because it's recursing too deep, it schedules unplug work right >>> away, so it will easily loop 100 times. Max blocked counts should be >>> adjusted to two (needs some testing before actually submitting the >>> change). But that still shouldn't cause any lock up. What happens if >>> you remove the 100 times limit? Does the machine hang on IO? >> >> Yes, it does. In fact, I had already verified that before sending the >> previous email. > > Hmmm.... it's supposed not to lock up although it can cause busy wait. The same problem still exitst in 2.6.25-rc9. As I understand, not all configurations are affected. So, perhaps I should bring this to the attention of those who are working on the scheduler. What do you think? Regards, Elias -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
