hi,

oops... yup, you've got it right on.  I'll change the pmaps to use
ubc_winshift instead of ubc_winsize.  if we just initialize ubc_winsize
from UBC_WINSHIFT in its definition then people would have to patch both
variables if they wanted to override the default size.

thanks,
-Chuck


On Tue, Mar 20, 2001 at 01:58:33PM -0500, Rafal Boni wrote:
> In message <200103200803.DAA11916@doppelganger.waterside.net>, I wrote: 
> 
> -> 	Has anything in UVM/UBC changed recently that could be related
> -> 	to the above panic?  I CVS updated my tree ~ 7pm EST on 3/19 and
> -> 	now my Indigo2 panics there (not that the SGImips kernel did a
> -> 	whole lot more than that, but now it's totally useless).
> -> 
> -> 	I haven't updated my x86 box, so this could be MIPS/SGI specific,
> -> 	but I figured I'd ask, go to bed and then hope answers arrive while
> -> 	I snooze.
> 
> It seems this is related to the change from `ubc_winsize' to `ubc_winshift'.
> The MIPS pmap module sizes the virtual space as follows:
> 
> 	start = VM_MIN_KERNEL_ADDRESS;
> 	end   = VM_MIN_KERNEL_ADDRESS + Sysmapsize * NBPG;
> 
>     where:
> 	Sysmapsize = (VM_PHYS_SIZE + ubc_nwins * ubc_winsize + 
> 		nbuf * MAXBSIZE + 16 * NCARGS + PAGER_MAP_SIZE) / NBPG + 
> 		(maxproc * UPAGES) + nkmempages;
> 
> *However*, when Sysmapsize is calculated, `ucb_winsize' is still zero (as
> UBC init runs much later and it's not set until ubc_init()).  
> 
> I imagine the easiest thing is to just initialize ubc_winsize from 
> ubc_winshift in uvm_bio.c... Was this not done for some reason other
> than forgetting to do it or overlooking it?
> 
> The other option (which seems like a lot of work for little gain), is 
> to purge ubc_winsize totally from the tree, but it certainly looks like
> this is not what Chuq intended (since it's used often even in uvm_bio.c).
> 
> Thoughts?
> --rafal
> 
> ----
> Rafal Boni                                                  rafal@mediaone.net