Messages in this thread |  | | Date | Mon, 25 Sep 2000 18:02:18 +0200 (CEST) | From | Ingo Molnar <> | Subject | Re: the new VMt |
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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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