Date: Sun, 10 Oct 1999 18:04:12 -0700 (PDT) From: Matthew Dillon <dillon@apollo.backplane.com> To: Poul-Henning Kamp <phk@critter.freebsd.dk> Cc: Peter Wemm <peter@netplex.com.au>, "Daniel C. Sobral" <dcs@newsguy.com>, cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/sys/vm vm_swap.c Message-ID: <199910110104.SAA18509@apollo.backplane.com> References: <15735.939576321@critter.freebsd.dk>
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:> If you implement a means to create unassociated (i.e. no major/minor
:> number at all) devices, the swap device can be converted to one
:> internally. We aren't going to get rid of the cdevsw structure, though.
:> Creating totally custom I/O interfaces is never a good idea.
:
:You don't need a dev_t, in fact one or two levels of indirection through
:vnop/devsw can be ripped right out by calling swstrategy() directly.
:
:--
:Poul-Henning Kamp FreeBSD coreteam member
We're not removing the device interface. It provides a reasonable
abstraction and a nice demark between swap_pager.c and vm_swap.c,
as well as potential flexibility that could be useful in the future
Removing it will not save time or much in the way of code space.
As far as the striping efficiency goes: The swap device abstraction
is already massively tuned for I/O efficiency, nothing you could possibly
do with a ccd or vinum will make it better. Additionally, there are
complexities related not only to the swapon code, but to (potentially)
future swapoff and prioritization calls that are not suited to other
pre-existing abstractions (such as vinum or ccd).
-Matt
Matthew Dillon
<dillon@backplane.com>
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