Date: Fri, 3 Dec 1999 11:58:29 -0700 (MST) From: "Justin T. Gibbs" <gibbs@narnia.plutotech.com> To: mjacob@feral.com Cc: scsi@FreeBSD.org Subject: Re: bounce buffers (was Re: Tape driver problems) Message-ID: <199912031858.LAA11735@narnia.plutotech.com> In-Reply-To: <Pine.BSF.4.05.9912031013460.12054-100000@semuta.feral.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. > 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. -- Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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