Messages in this thread |  | | Subject | Re: Hardwired drivers are going away? | From | Andi Kleen <> | Date | 15 Jan 2002 13:16:04 +0100 |
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peter@horizon.com writes:
> 1) The main kernel is contiguous in physical memory and is mapped with > large (4 MB) pages. This reduces pressure on the TLB. Modules are > loaded in vmalloc memory, which uses small pages, and therefore > competes for TLB space. This is a performance penalty, especially > as most current machines have undersized TLBs already. (A 64-entry > TLB with 4K pages maps 256K at a time. On-chip L2 caches are this > large or larger. Thus, as a crude approximation, every L2 miss also > causes a TLB miss.)
-aa tries to load modules into the linear mapping when possible. That usually works when you load the modules early when the memory isn't that fragmented yet.
I agree on that trying to put everything into modules isn't a good idea, especially because of your second point.
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