Messages in this thread |  | | Date | Wed, 30 Aug 2000 01:31:43 +0200 | From | Jens Axboe <> | Subject | Re: [PATCH] Fix disk statistic reporting to include all disks |
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On Tue, Aug 29 2000, Linus Torvalds wrote: > > Sounds sane, but what about drivers that don't really use the request > > queue structure? Stuff like lvm, md, rd (with Neil's patch to fix the > > lru_list deadlock), and probably new loop. > > Every single driver must have a request_queue: as far as the ll_rw_block > layer is concerned, a NULL request-queue means that the device doesn't > exist. It will even print out a message saying so.. > > I'm not sure what you mean about lvm/md/rd not having request queues.
Maybe I wasn't very clear... What I mean is that drivers that use blk_queue_make_request (such as md) are handed buffers directly and don't get requests added to their queues in the regular sense, instead they remap b_rdev before ll_rw_blk gets the queue for the device and adds them to the destination queue.
So per request accounting isn't done for md currently, although (as per your next mail) I do agree that having statistics for both makes sense.
-- * Jens Axboe <axboe@suse.de> * SuSE Labs - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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