Date: Mon, 11 Oct 1999 18:40:06 +0800 From: Peter Wemm <peter@netplex.com.au> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: Poul-Henning Kamp <phk@critter.freebsd.dk>, "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: <19991011104006.AE4631CC8@overcee.netplex.com.au> In-Reply-To: Your message of "Mon, 11 Oct 1999 00:09:58 MST." <199910110709.AAA20043@apollo.backplane.com>
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Matthew Dillon wrote:
> :>
> :> 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.
> :
> :The swap *device* is non-functional and doesn't *do* anything except
> :provide a subroutine call in a very roundabout way. I think it would be
> :far better to avoid an indirection via the VOP_* system for no useful gain
> :and do something like the aooended patch (which works perfectly here BTW,
> :even under heavy swap load on multiple disks). Further (micro)
> :optimizations are possible, for example pbgetvp() is used to get a p-buffer
> :that's associated with swapdev_vp and the device. The device isn't used
> :and presently vn_todev(vp) ends up returning NODEV. swapdev_vp is kinda
> :orphaned with this change but still works ok. p-buffers are created being
>
> Gentlemen. You might as well stop. I've said it before and I
> will say it again: Nobody is screwing around with the swap
> subsytem. I spent a lot of time on that subsytem, including weeks
> of testing. I am essentially the maintainer for it, and I am not
> going to allow people to mess with it based on a few hacks. Just
> because the swap subsystem uses a small subset of the device
> interface doesn't mean you can hack it up to remove it. You are not
> 'fixing' anything by doing so. You aren't making the system more reliabl
e,
> you aren't making the system run better. You are just making my job
> harder by forcing me to retest everything. So it isn't going to happen.
Oh come on now! Your "testing" didn't even find that reading /dev/drum was
an instant guaranteed system panic. This patch does not change a thing
except remove dead code that is almost certain to break shortly.
Cheers,
-Peter
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