[ On Monday, April 22, 2002 at 20:14:45 (+0100), Stephen Borrill wrote: ]
> Subject: Re: pmap panics on 1.4.3
>
> OK, I put this up to 24 * 1024 * 1024 / CLBYTES (pity you can't put a
> formula in your kernel config file which means a lot of digging around to
> find a value for CLBYTES).

For many paramaters you can, so long as you stick to syntax OK for the
preprocessor.

For example I think I've tested both of these (though they're currently
commented out in all the kernels I'm building these days):

    options	NKMEMPAGES="((24 * 1024 * 1024) >> PAGE_SHIFT)	# should use btoc()?
    options	BUFPAGES="btoc(10 * 1024 * 1024)"

Those "options" just show up on the R.H.S. of #define's:

$ cat opt_kmempages.h                                              
#define NKMEMPAGES_MAX  ((128 * 1024 * 1024) >> PAGE_SHIFT)
#define NKMEMPAGES_MIN  ((6 * 1024 * 1024) >> PAGE_SHIFT)
#define NKMEMPAGES      ((24 * 1024 * 1024) >> PAGE_SHIFT)
$ cat opt_bufcache.h                                               
#define NBUF    0x384
#define BUFPAGES        btoc(10*1024*1024)
/* option `BUFCACHE' not defined */


-- 
								Greg A. Woods

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