Messages in this thread | | | Date | Wed, 16 Jan 2002 17:34:26 -0200 (BRST) | From | Rik van Riel <> | Subject | Re: pte-highmem-5 |
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On Wed, 16 Jan 2002, Linus Torvalds wrote:
> - do the highmem pte bouncing only for CONFIG_X86_PAE: with less then 4GB > of RAM this doesn't seem to matter all that much (rule of thumb: we > need about 1% of memory for page tables).
Actually, with 100 processes mapping a 1 GB area of shared memory, you'll need about 100 MB of page tables or 10% of the SHM segment. This rises even further with PAE and/or more processes.
The page table cost for heavily shared memory segments is really getting out of hand, IMHO ... it might be worth it to set aside a separate memory zone and use 4 MB pages for the SHM segment.
regards,
Rik -- "Linux holds advantages over the single-vendor commercial OS" -- Microsoft's "Competing with Linux" document
http://www.surriel.com/ http://distro.conectiva.com/
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