Messages in this thread |  | | Date | Thu, 28 Dec 2000 23:17:22 +0100 | From | Andi Kleen <> | Subject | Re: test13-pre5 |
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On Thu, Dec 28, 2000 at 12:59:22PM -0800, Linus Torvalds wrote: > - we absolutely do _not_ want to make "struct page" bigger. We can't > afford to just throw away another 8 bytes per page on adding a new list > structure, I feel. Even if this would be the simplest solution.
BTW..
The current 2.4 struct page could be already shortened a lot, saving a lot of cache. (first number for 32bit, second for 64bit)
- Do not compile virtual in when the kernel does not support highmem (saves 4/8 bytes) - Instead of having a zone pointer mask use a 8 or 16 byte index into a zone table. On a modern CPU it is much cheaper to do the and/shifts than to do even a single cache miss during page aging. On a lot of systems that zone index could be hardcoded to 0 anyways, giving better code. - Instead of using 4/8 bytes for the age use only 16bit (FreeBSD which has the same swapping algorithm even only uses 8bit) - Remove the waitqueue debugging (obvious @) - flags can be __u32 on 64bit hosts, sharing 64bit with something that is tolerant to async updates (e.g. the zone table index or the index) - index could be probably u32 instead of unsigned long, saving 4 bytes on i386
Would you consider patches for any of these points?
-Andi
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