Confusing BKVASIZE

From: Jung-uk Kim (jkim_at_niksun.com)
Date: 08/04/03

  • Next message: Greg 'groggy' Lehey: "Re: headsup: swap_pager.c" 
    To: freebsd-arch@freebsd.org
Date: Mon, 4 Aug 2003 14:48:54 -0400

    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
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  • Next message: Greg 'groggy' Lehey: "Re: headsup: swap_pager.c"