Pagemap Rounding #558
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Pagemap Rounding #558
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nwf-msr
suggested changes
Sep 16, 2022
| auto end = pointer_align_down( | ||
| // Calculate range in pagemap that is associated to this space. | ||
| // Over calculate to cover any unaligned parts at either end. | ||
| auto b_align = pointer_align_down(b, bits::one_at_bit(GRANULARITY_BITS)); |
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While this might take b_align below b, and so logically start our PageMap out of bounds, that's OK because we never access the MetaEntry-s associated with the PageMap itself?
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Is b_align only used in address and size computations? If yes, then would it be clearer and safer to get the address of b and align the address down? That way no wild pointer exists.
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So I have tried to make this capability less code as it is just addresses like you suggest:
9542fbe
ihaller
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Sep 16, 2022
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I am very happy with this change now. |
Check for possible overlap between heap and pagemap, but writing and reading the heap.
This commit allows the pagemap to return unaligned range of memory. This means that bump allocation of multiple pagemaps doesn't waste as much space.
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This PR ensures that if a pagemap is used in a fixed region that has very large granularity it does require undue additional alignment.