Messages in this thread | | | Date | Thu, 1 Mar 2001 14:39:43 +0100 | From | Jens Axboe <> | Subject | Re: NBD Cleanup patch and bugfix in ll_rw_blk.c |
| |
On Wed, Feb 28 2001, Linus Torvalds wrote: > >I think most of the "we want to disable plugging" behaviour stems > >from the way task queues behave. Once somebody starts a tq_disk > >run, the list is fried and walked one by one. Both old loop > >and nbd drop the io_request_lock and block, possibly waiting > >for I/O to be done (at least the loop case, don't know about > >ndb). But this I/O won't be done just because the target plug every > >now and then just happens to be queued behind the nbd/loop one and a new > >tq_disk run won't start it. > > Ugh. > > How about loop/ndb intercepting the damn requests at the "elevator" > layer - that way you see every one of them, and the actual request > function might as well just be a no-op?
I've suggested that before, turn ndb into ndb_make_request style driver and all of this will disappear. I'll give it a shot.
-- Jens Axboe
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |