[ On Sunday, December 8, 2002 at 11:02:54 (-0800), Chuck Silvers wrote: ]
> Subject: Re: NetBSD1.6 UVM problem?
>
> yes, the heuristic for determining when to start killing processes
> when no swap is available doesn't work so well when there's no swap
> configured.  in this case, it would be useful to count RAM that isn't
> reserved for other usage types as potentially available for swap-backed
> allocation.   all the places in uvm_fault() that return ENOMEM currently
> use "uvmexp.swpgonly == uvmexp.swpages" as the indicator that sleeping
> won't free up any more memory that could be used for anons, but when
> there's no swap then both sides of that comparison are always zero.
> 
> we could replace that with something more like
> 
> 	int t;
> 
> 	t = uvmexp.active + uvmexp.inactive + uvmexp.free;
> 	if (uvmexp.swpgonly == uvmexp.swpages &&
>             uvmexp.filepages <= ((t * uvmexp.filemin) >> 8) &&
> 	    uvmexp.execpages <= ((t * uvmexp.execmin) >> 8)) {
> 		return ENOMEM;
> 	}
> 
> (and yea, I should make some macros for doing the fixed-point math.)
> this means that we will only start killing processes when swap is full
> and the file and exec pages have been reduced to their minimum levels.
> 
> does that do anything useful for you?

Oh, yes please!  I think this will help a lot!

-- 
								Greg A. Woods

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