Re: the new VMt

On Mon, 25 Sep 2000, Andrea Arcangeli wrote:

Ingo's point is that the underlined line won't ever happen in the
first place

please dont misinterpret my point ...

Frankly, how often do we allocate multi-order pages? I've just made quick
statistics wrt. how allocation orders are distributed on a more or less
typical system:

	(ALLOC ORDER)
	0: 167081
	1: 850
	2: 16
	3: 25
	4: 0
	5: 1
	6: 0
	7: 2
	8: 13
	9: 5

ie. 99.45% of all allocations are single-page! 0.50% is the 8kb
task-structure. The rest is 0.05%.

i'm not talking about 4MB contiguous physical allocations having to
succeed on a 8MB box. I'm talking about 99% of the simple allocation
points not having to worry about a NULL pointer. (not checking for NULL is
one of the most common allocation-related bug that beats low-RAM systems.)

	Ingo


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