Use extreme assertion for metadata mapped assert #812
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The `assert_metadata_mapped` method uses the `mmap` system call and expects a failure. This is too costly even for debug builds. We disable it unless the "extreme_assertions" feature is enabled.
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The
assert_metadata_mappedmethod uses themmapsystem call and expects a failure. This is too costly even for debug builds. We disable it unless the "extreme_assertions" feature is enabled.This issue has a greater impact on VMs that use the valid-object bit (VO bit) metadata because the metadata is accessed on every object allocation, and there is such an assertion in metadata access.
The
rrdebugging tool seems to record every system call. This PR also makesrrmuch faster (e.g. 14.20s vs 0.202s when running hello world in Ruby).How to test
Compile mmtk-core with debug build, and use
straceto run the VM. Before this PR, a hello world program in Ruby (using mmtk-ruby) shall have 400000+mmapinvocations returning -1 witherrno = EEXIST; with this PR, they will all disappear.