Mmap refactoring #296
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Mmap refactoring #296
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qinsoon
added
the
PR-testing
onces in side metadata
javadamiri
reviewed
Apr 29, 2021
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k-sareen
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to k-sareen/mmtk-core
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this pull request
Jun 10, 2021
* Add unit tests for mmap and some refactoring * Replace dzmmap with dzmmap_noreplace in almost all use cases except the onces in side metadata * Make dzmmap unsafe. Add some comments. * mmap_noreserve maps memory with PROT_NONE. We have to do dzmmap before actually use it.
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This PR refactors our mmap implementation and uses. It addresses #244, and it works towards #257 (though more work is needed for #257).
This PR:
dzmmap()withdzmmap_noreplace().mmap_noreserve()from read/write toPROT_NONEso it serves the purpose of reserving address range. The memory is not usable before another mmap or mprotect.dzmmap()unsafe, as it may overwrite existing mappings. The only place it is now used is in side metadata where we reserve address range withmmap_noreserve()and then usedzmmap()to map it.check_is_mapped()topanic_if_unmapped(). The function is more than just checking mapping - it may actually mmap memory as a side effect. We should simply panic if we mmap any memory in the function.util::memoryso they deal with errors in the same way.util::memory.