Il 21/01/2013 13:35, Kevin Wolf ha scritto: > I'm wondering if a whole bitmap is really appropriate when you have at > most 16 parallel requests in flight. Other places in qemu (like > copy-on-read or qcow2 cluster allocation) use lists of in-flight > requests instead. > > I'm not requesting a change here, just wondering what the reasons are > and whether this, or the other places, or none of both should be changed > long term.
The reason is simply that the code is reasoning in bitmaps a lot (cow_bitmap and of course the dirty bitmap), so it was a natural pick and the memory usage is not important. It is simpler and more efficient than a linear scan. I have the required information already in the MirrorOp struct indeed, but I didn't need those in a list. Paolo
