The problem with unmount which the patches address and about which the report here was (as far as I understood it) was not so much the number of IO generated (though it makes things worse) but the fact that the sync on unmount had changed from being asynchronous to synchronous. That means every single block pending to be flushed is written and waited for. So no merging of IO is and can be done which makes things really slow.
The description of the other patch I was seeing described a problem in writeback, where it could happen that flush tried to write out buffers while the producer would add more data and by that would prevent other things to get written. The problem you describe seems to be even a third thing which rather sounds like a problem in ext4/jdb2 than the generic writeback code (at least from reading the description). -- giant IO delays on unmount https://bugs.launchpad.net/bugs/585092 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
