Messages in this thread | | | Date | Tue, 22 Apr 2003 07:32:36 -0700 | From | "Martin J. Bligh" <> | Subject | Re: objrmap and vmtruncate |
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> It also makes it easy to calculate the overhead of the pte chains: twice > the amount of pagetable overhead. Ie. with 32-bit pte's it's +8 bytes > overhead, or +0.2% of RAM overhead per mapped page, using a 4K page. With > 64-bit ptes on 32-bit platforms (PAE), the overhead is still 8 bytes. On > 64-bit platforms using 8K pages the overhead is still +0.2% of RAM, in > additionl to the 0.1% of RAM overhead for the pte itself. The worst-case > is 64-bit platforms with a 4K pagesize, there the overhead is +0.4% of > RAM, in addition to the 0.2% overhead caused by the pte itself.
Oh, BTW. You're assuming no sharing of any pages in the above. Look what happens if 1000 processes share the same page ...
M.
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