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Newsgroups: comp.os.386bsd.questions
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From: bad@flatlin.ka.sub.org (Christoph Badura)
Subject: Re: Q on buffer cache
Organization: Guru Systems/Funware Department
Date: Mon, 6 Sep 1993 11:06:39 GMT
Message-ID: <CCxIv4.980@flatlin.ka.sub.org>
References: <CCxCy0.L78@sztaki.hu>
Lines: 18
In <CCxCy0.L78@sztaki.hu> pink@fsz.bme.hu (Szabolcs Sziget (PinkPanther)) writes:
>vn_rdwr() calls to fill the given buffer.(Doing file io from device driver is not nice!) This works very well until the system runs out of buffers. Then the strategy tries to fill its buffer with the read, which won't return until it gets an empty buffer to read but there won't be empty buffer until strategy returns: DEADLOCK!
You might want to try and grab a buffer in the open function and use
that for IO. This scheme worked for us in a similar situation years
ago.
I also have a driver lying around that does exactly what you want.
However, that source is an old BSDish driver hacked to work under
System V.
PS. please keep you lines shorter than about 76 characters.
--
Christoph Badura --- bad@flatlin.ka.sub.org --- +49 721 606137
Personally, I don't care whether someone is cool enough to quote Doug
Gwyn--I only care whether Doug Gwyn is cool enough to quote. -- Larry Wall