On Mon, Aug 13, 2012 at 11:02:08AM -0500, Eric Sandeen wrote: > > Looks ok to me; I think this just further optimizes what was done > in > > 8a57d9d61a6e361c7bb159dda797672c1df1a691 > ext4: check for a good block group before loading buddy pages > > correct? Yes, that's right; it's a further optimization. I can think of an additional optimization where if we are reading the block bitmap for block group N, and the block bitmap for block group N+1 hasn't been read before (so we don't have buddy bitmap stats), and the block bitmap for bg N+1 is adjacent for bg N, we should read both at the same time. (And this could be generalized for N+2, N+3, etc.) I'm not entirely sure whether it's worth the effort, but I suspect for very full file systems, it might be very well be. This is a more general case of the problem where most people only benchmark mostly empty file systems, and my experience has been that above 70-80% utilization, our performance starts to fall off. And while disk space is cheap, it's not _that_ cheap, and there are always customers who insist on using file systems up to a utilization of 99%, and expect the same performance as when the file system was freshly formated. :-( - 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
