On Sat, 2009-08-29 at 19:03 -0400, Christoph Hellwig wrote: > > The commands are conceptually writes, and in the case of IDE and SCSI > commands actually are writes. They were only reads because we thought > that would interact better with the elevators. Now the elevators know > about discard requests, that advantage no longer exists. Can you drop the final sentence of that? It isn't true, and I never said it. s/. Now.*/, but that isn't necessary, and making them writes makes it easier for the low-level IDE and SCSI code to cope with the fact that the command has to be sent with a payload./ The elevators _still_ don't know about discards, and will still let reads and writes (and discards, which are just a special case of writes) to the same sector all cross each other on the queue unless there's some external factor to prevent it. -- David Woodhouse Open Source Technology Centre David.Woodhouse@xxxxxxxxx Intel Corporation -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
