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Date:      Thu, 18 Dec 1997 23:16:48 +1100 (EDT)
From:      Darren Reed <avalon@coombs.anu.edu.au>
To:        gurney_j@resnet.uoregon.edu
Cc:        freebsd-hackers@FreeBSD.ORG
Subject:   Re: converting drivers to dynamic memory...
Message-ID:  <199712181217.EAA13580@hub.freebsd.org>
In-Reply-To: <19971218035032.46460@hydrogen.nike.efn.org> from "John-Mark Gurney" at Dec 18, 97 03:50:32 am

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In some mail from John-Mark Gurney, sie said:
> 
> well...  one of the things that will need to be done in preperation
> for moving to a dynamic system which will be required by the bus/device
> code, we will need to eliminate ALL static datat that depends upon
> Ndevice to size itself.
> 
> There are two ways that we can fix this problem.  The first (and
> technically the best) is to be extend many of the calling functions
> to pass around a void * pointer that will point to that devices
> resources.  Though this is technically best, it will require that
> most major parts of the kernel be significantly changes.
> 
> The second solution is to continue to use the major/minor code scheme,
> but use a binary tree or a B-tree to obtain the private data.  This
> can cause a performance impact if we use if for things like the sio,
> but this can be fixed by changing the interrupt interface.

> I think that we should go with the second solution as it will be
> initalially easier to do.  I have B-tree code already writen, (I was
> writing it for another use in my bus/device code) which we could use
> to access this information.  (Some people will say, why not linked
> lists, and then I will say, sio, I have 12 ports on my term server,
> plus you get better data density)

I guess the question is, do you want a `quick hack' or a real solution to
fix and addres the problem ?

How many hours did you spend on the B-Tree stuff and how many do you
expect it would take to do it the other way ?

"Do it once and do it right."




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