Re: [PATCH] 4/4 block: explicit plugging

[Jens Axboe <jens.axboe@oracle.com>]

On Thu, Jan 04 2007, Nick Piggin wrote:
> Jens Axboe wrote:
> >Nick writes:
> >
> >This is a patch to perform block device plugging explicitly in the 
> >submitting
> >process context rather than implicitly by the block device.
> 
> Hi Jens,
> 
> Hey thanks for doing so much hard work with this, I couldn't have fixed
> all the block layer stuff myself. QRCU looks like a good solution for the
> barrier/sync operations (/me worried that one wouldn't exist), and a
> novel use of RCU!
> 
> The only thing I had been thinking about before it is ready for primetime
> -- as far as the VM side of things goes -- is whether we should change
> the hard calls to address_space operations, such that they might be
> avoided or customised when there is no backing block device?
> 
> I'm sure the answer to this is "yes", so I have an idea for a simple
> implementation... but I'd like to hear thoughts from network fs / raid
> people?

I suppose that would be the proper thing to do, for non __make_request()
operated backing devices. I'll add the hooks, then we can cook up a raid
implementation if need be.

-- 
Jens Axboe