On 2011-04-18 11:40, Hannes Reinecke wrote: > On 04/18/2011 11:19 AM, hch@xxxxxxxxxxxxx wrote: >> Btw, I really start to wonder if the request level is the right place >> to do this on-stack plugging. Wouldn't it be better to just plug >> bios in the on-stack queue? That way we could also stop doing the >> special case merging when adding to the plug list, and leave all the >> merging / I/O schedule logic in the __make_request path. Probably >> not .39 material, but worth a prototype? >> >> Also what this dicussion brought up is that the block layer data >> structures are highly confusing. Using a small subset of the >> request_queue also for make_request based driver just doesn't make >> sense. It seems like we should try to migrate the required state >> to struct gendisk, and submit I/O through a block_device_ops.submit >> method, leaving the request_queue as an internal abstraction for >> the request based drivers. >> > Good point. > It would also help us we the device-mapper redesign agk and myself > discussed at LSF. Having a block_device_ops.submit function would > allow us remap the actual request queue generically; and we would > even be able to address more than one request queue, which sounds > awfully similar to what Jens is trying to do ... The multiqueue bits would still have one request_queue, but multiple queueing structures (I called those blk_queue_ctx, iirc). -- Jens Axboe -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
