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From: Jung-uk Kim <jkim@niksun.com>
Organization: Niksun, Inc.
To: freebsd-arch@freebsd.org
Date: Mon, 4 Aug 2003 14:48:54 -0400
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Message-Id: <200308041448.54790.jkim@niksun.com>
Subject: Confusing BKVASIZE
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As you know, BKVASIZE is 16K:

http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/sys/param.h#rev1.63

Default UFS block size is also 16K:

http://www.freebsd.org/cgi/cvsweb.cgi/src/sbin/newfs/newfs.c#rev1.46

But src/sys/sys/param.h says:

	'The default (BKVASIZE) is 16384, roughly 2x the block size
used by a normal UFS filesystem.'

This is not true any more and it is really confusing.  In fact, I found many
confusing instances, e.g.

src/sys/kern/vfs_bio.c:
/*
 * To support extreme low-memory systems, make sure hidirtybuffers cannot
 * eat up all available buffer space.  This occurs when our minimum cannot
 * be met.  We try to size hidirtybuffers to 3/4 our buffer space assuming
 * BKVASIZE'd (8K) buffers.
 */

I cannot believe comments any more and this is clearly error-prone. :-(

Can anybody clean this mess up?

Thanks,

Jung-uk Kim