[patch 0/4] [RFC] Another proportional weight IO controller

Ryo Tsuruta ryov at valinux.co.jp
Thu Nov 27 19:09:54 PST 2008


Hi,

> > > I don't come up with any use case, but I would like to make the
> > > resource controller more flexible. Actually, a certain block device
> > > that I'm using does not use the I/O scheduler.
> > 
> > Isn't it equivalent to using No-op? If yes, then it should not be an
> > issue?
> 
> No, it is not equivalent. When using devices drivers that provide their
> own make_request_fn() (check for devices that invoke
> blk_queue_make_request() at initialization time) bios entering the block
> layer can go directly to the device driver and from there to the device.

As Fernando said, that device driver invokes blk_queue_make_request(),

Thanks,
Ryo Tsuruta


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