On Wed, Jun 25 2008, Matthew Wilcox wrote: > On Wed, Jun 25, 2008 at 06:57:59PM +0200, Jens Axboe wrote: > > Precisely, merging and fairness is a big part of it. Plus, doing this in > > sd is just a blatant layer violation. > > I'm fine with tweaking the elevators to know about low-latency seeks. > But please stop describing it as "a blatant layering violation". > It's nothing of the sort. It's setting a default at a point where we > find out the information which would guide us. Uhm, but it IS "a blatant layering violation", it's doing things from the wrong side up :-) > I haven't looked into doing this in udev yet; I've got caught up in > another project. In any case, it seems like there's no role for udev > any more, so I'll probably not spend any more time on this unless there's > some need. I don't think udev is a particularly good idea either. My plan was to introduce device profiles for the queue, but it is probably a bad idea to over-engineer this. So I'll keep it simple, stick to a 'zero cost seek' flag instead and allow drivers to signal that. libata/ide needs to check the ID page word to detect SSD drives as well, so they need a few lines of change too. I'll just stick the block bit in the 2.6.27 pending queue and let the other patches go through Jeff/James/Bart. -- Jens Axboe -- 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
