Messages in this thread | | | Date | Fri, 13 Sep 2002 18:46:52 +0530 | From | Suparna Bhattacharya <> | Subject | Re: [PATCH] 2.5 port of aio-20020619 for raw devices |
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On Thu, Sep 12, 2002 at 02:35:40PM -0400, Benjamin LaHaise wrote: > On Thu, Sep 12, 2002 at 02:21:08PM -0400, Shailabh Nagar wrote: > > I just did a rough port of the raw device part of the aio-20020619.diff > > over to 2.5.32 using the 2.5 aio API published so far. The changeset > > comments are below. The patch hasn't been tested. Its only guaranteed > > to compile. > > > > I'd like to reiterate that this is not a fork of aio kernel code > > development or any attempt to question Ben's role as maintainer ! This > > was only an exercise in porting to enable a comparison of the older > > (2.4) approach with whatever's coming soon. > > > > Comments are invited on all aspects of the design and implementation. > > The generic aio <-> kvec functions were found to not work well, and > the chunking code needs to actually pipeline data for decent io thruput. > Short story: the raw device code must be rewritten using the dio code > that akpm introduced.
How async (degree on non-blocking nature of steps in the async state machine) do we want to be when we use the dio pipelining code ? (besides making the wait for dio completion bit async, of course)
Some key places where we can potentially block are when mapping the user pages, as part of get_blocks, when alloc'ing a bio, when issuing submit_bio (i.e. waiting for the request pipeline to drain out or free up slots). I guess, at least the last one would be addressed ... not sure what the plans for the rest are.
Regards Suparna
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