On Thursday 13 September 2007 23:03, David Chinner wrote: > On Thu, Sep 13, 2007 at 03:23:21AM +1000, Nick Piggin wrote: > > Well, it may not be easy to _fix_, but it's easy to try a few > > improvements ;) > > > > How do I make an image and run a workload that will coerce XFS into > > doing a significant number of vmaps? > > # mkfs.xfs -n size=16384 <dev> > > to create a filesystem with a 16k directory block size on a 4k page > machine. > > Then just do operations on directories with lots of files in them > (tens of thousands). Every directory operation will require at > least one vmap in this situation - e.g. a traversal will result in > lots and lots of blocks being read that will require vmap() for every > directory block read from disk and an unmap almost immediately > afterwards when the reference is dropped.... Ah, wow, thanks: I can reproduce it. - 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
