El 22/03/11 10:03, Andrea Arcangeli escribió:
I asked yesterday by PM to Alex if the mouse pointer moves or not during the stalls (if it doesn't that may be a scheduler issue with the compaction irq disabled and lack of cond_resched) and to try aa.git. Upstream still misses several compaction improvements that we did over the last weeks and that I've in my queue and that are in -mm as well. So before making more changes, considering the stack traces looks very healthy now, I'd wait to be sure the hangs aren't already solved by any of the other scheduling/irq latency fixes. I guess they aren't going to help but it worth a try. Verifying if this happens with a more optimal filesystem like ext4 I think is also interesting, it may be something in udf internal locking that gets in the way of compaction. If we still have a problem with current aa.git and ext4, then I'd hope we can find some other more genuine bit to improve like the bits we've improved so far, but if there's nothing wrong and it gets unfixable, then my preference would be to either create a defrag mode that is in between "yes/no", or alternatively to be simpler and make the default between defrag yes|no configurable at build time and through a command line in grub, and hope that SLUB doesn't clashes on it too. The current "default" is optimal for several server environments where we know most of the allocations are long lived. So we want to still have an option to be as reliable as we are toady for those.
I have just tested aa.git as of today, with the USB stick formatted as FAT32. I could no longer reproduce the stalls. There was no need to format as ext4. No /proc workarounds required. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>