On Tue, Sep 08, 2009 at 06:56:23PM +0200, Peter Zijlstra wrote: > On Tue, 2009-09-08 at 12:29 -0400, Chris Mason wrote: > > Either way, if pdflush or the bdi thread or whoever ends up switching to > > another file during a big streaming write, the end result is that we > > fragment. We may fragment the file (ext4) or we may fragment the > > writeback (xfs), but the end result isn't good. > > OK, so what we want is for a way to re-enter the whole > writeback_inodes() path onto the same file, right? No, that would take use back to the Bad Old Days where one large file write can starve out the other 10,000 small files that need to be written. The old writeback code used to end up in this way because it didn't rotate large files to the back of the dirty inode queue once wbc->nr_to_write was exhausted. This could cause files not to be written back for tens of minutes.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- 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
