On Tue, Sep 11, 2007 at 04:00:17PM +1000, Nick Piggin wrote:
XFS already has persistence across the object life time (which can be many
tens of seconds for a frequently used buffer) and it also does batched
unmapping of objects as well.
Yes, we already do the many of these things (via xfs_buf_offset()), but
that is not good enough for something like a memcpy that spans multiple
pages in a large block (think btree block compaction, splits and recombines).
IOWs, we already play these vmap harm-minimisation games in the places
where we can, but still the overhead is high and something we'd prefer
to be able to avoid.
SGI Australian Software Group