On Fri, Oct 26, 2012 at 09:23:39PM +0800, Zheng Liu wrote: > + * 3. performance analysis > + * -- overhead > + * 1. Apart from operations on a delayed extent tree, we need to > + * down_write(inode->i_data_sem) in delayed write path to maintain delayed > + * extent tree, this can have impact on parallel read-write and write-write Hi Zheng, I can fix this up, before I finalize your commit, but I just want to check. I believe this comment is out of date --- we are now using a r/w spinlock, i_es_lock, yes? Since we never hold the spinlock for very long, I would be surprised if this is going to be a scalability bottleneck (too bad Eric doesn't have access to the big SMP machine that he used to use to help us do our scalability testing, so we could check to be sure). - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html