Date: Fri, 3 Dec 1999 11:11:22 -0800 (PST) From: Matthew Jacob <mjacob@feral.com> To: "Justin T. Gibbs" <gibbs@narnia.plutotech.com> Cc: scsi@FreeBSD.org Subject: Re: bounce buffers (was Re: Tape driver problems) Message-ID: <Pine.BSF.4.05.9912031110520.12054-100000@semuta.feral.com> In-Reply-To: <199912031858.LAA11735@narnia.plutotech.com>
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> In article <Pine.BSF.4.05.9912031013460.12054-100000@semuta.feral.com> you wrote: > >> >You pay for what you get. If you are really still using ISADMA mass > >> >storage, blow 128k or MAXPHYS already.. IMO... > >> > >> We do, but we allocate and dole it out as individual pages. NetBSD allocates > >> MAXPHYS per possible transaction on each card which turns out to be 1MB of > >> < 16MB memory per card. This doesn't scale. > > > > It's not important that ISADMA scales. If somebody wants to put 4 1542s in > > a system, they can pay a lot for the privilege of not buying 2940s. > > The system may not boot if you cannot find the necessary space. You're > probably also guaranteed that your sound card fails to work too. *cough*.... > > > Still, it needn't be per card. It can be per-system and it's not for wired > > down usage (or you could add a flag for wired down usage). > > Right. There are better ways to do this and at some point it will happen. > I just need to decide how I want to track fragmentation and decide which > fragments to coaless/align. This type of thing doesn't just happen for > ISA bus stuff (other devices may have a limited supply of S/G entries), so > I'd like to take a shot at making it somewhat smart. A shot delayed is a shot denied.... -matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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