Cargo Features
MMTk has no features set by default.
[dependencies]
mmtk = { version = "0.24.0", features = ["perf_counter", "mock_test", "vm_space", "ro_space", "code_space", "vo_bit", "is_mmtk_object", "object_pinning", "immix_non_moving", "sticky_immix_non_moving_nursery", "immix_smaller_block", "immix_zero_on_release", "sanity", "analysis", "nogc_lock_free", "nogc_no_zeroing", "single_worker", "extreme_assertions", "nogc_multi_space", "work_packet_stats", "malloc_counted_size", "count_live_bytes_in_gc", "bpftrace_workaround", "malloc_mimalloc", "malloc_jemalloc", "malloc_native_mimalloc", "eager_sweeping", "malloc_mark_sweep"] }- perf_counter = pfm
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This feature is only supported on x86-64 for now
It's manually added to CI scripts - mock_test
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This feature is only used for tests with MockVM.
CI scripts run those tests with this feature.Affects
test_util::fixtures,test_util::mock_method,test_util::mock_vm… - vm_space
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.github/scripts/ci-common.sh extracts features from the following part (including from comments). So be careful when editing or adding stuff to the section below.
Do not modify the following line - ci-common.sh matches it -- Non mutually exclusive features --
spaces with different semantics
A VM-allocated/managed space. A binding could use this for their boot image, metadata space, etc. FIXME: This is not properly implemented yet (it is only working for JikesRVM): https://github.com/mmtk/mmtk-core/issues/415 If a binding would need to trace/scan objects that is allocated and managed by the VM,
ActivePlan::vm_trace_object()is an alternative.Affects
memory_manager::set_vm_space,global::BasePlan.vm_space,policy::vmspace… - ro_space
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A readonly space.
TODO: This is not properly implemented yet. We currently use an immortal space instead, and do not guarantee read-only semantics.Affects
global::BasePlan.ro_space… - code_space
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A code space with execution permission.
TODO: This is not properly implemented yet. We currently use an immortal space instead, and all our spaces have execution permission at the moment.Affects
global::BasePlan.code_space,global::BasePlan.code_lo_space… - vo_bit is_mmtk_object? = eager_sweeping
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Global valid object (VO) bit metadata. The VO bit is set when an object is allocated, and cleared when the GC determines it is dead. See
src/util/metadata/vo_bit/mod.rseager_sweeping: VO bits for dead objects must have been cleared by the end of each GC. Native MarkSweep only ensures this in eager sweeping mode.
- is_mmtk_object = vo_bit
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conservative garbage collection support
Affects
memory_manager::is_mmtk_object,metadata::has_object_alloced_by_malloc,sft::SFT.is_mmtk_object,util::is_mmtk_object… - object_pinning
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Enable object pinning, in particular, enable pinning/unpinning, and its metadata
Affects
memory_manager::pin_object,memory_manager::unpin_object,memory_manager::is_pinned,sft::SFT.pin_object,sft::SFT.unpin_object,sft::SFT.is_object_pinned… - immix_non_moving
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The following two features are useful for using Immix for VMs that do not support moving GC.
Disable any object copying in Immix. This makes Immix a non-moving policy. - sticky_immix_non_moving_nursery
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Disable any object copying in nursery GC for Sticky Immix while allowing other kinds of copying.
immix_non_movingdisables all kinds of copying in Immix, so this feature is not needed ifimmix_non_movingis in use. - immix_smaller_block
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Reduce block size for ImmixSpace. This mitigates fragmentation when defrag is disabled.
- immix_zero_on_release
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Zero the unmarked lines after a GC cycle in immix. This helps debug untraced objects.
- sanity
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Run sanity GC
Affects
sft::SFT.is_sane,gc_work::ProcessEdgesWork.cache_roots_for_sanity_gc… - analysis
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Run analysis
Affects
allocator::AllocatorContext.analysis_manager… - nogc_lock_free nogc_no_zeroing?
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Use lock free variant of NoGC
- nogc_no_zeroing = nogc_lock_free
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Use lock free with no zeroing NoGC
- single_worker
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For using a single GC thread
Q: Why do we need this as a compile time flat? We can always set the number of GC threads through options. - extreme_assertions
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To run expensive comprehensive runtime checks, such as checking duplicate edges
Affects
sanity::verify_bzero,sanity::verify_bset,sanity::verify_bcopy,sanity::verify_load,sanity::verify_store,sanity::verify_update… - nogc_multi_space
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Enable multiple spaces for NoGC, each allocator maps to an individual ImmortalSpace.
- work_packet_stats
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To collect statistics for each GC work packet. Enabling this may introduce a small overhead (several percentage slowdown on benchmark time).
- malloc_counted_size
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Count the malloc'd memory into the heap size
Affects
memory_manager::counted_malloc,memory_manager::counted_calloc,memory_manager::realloc_with_old_size,memory_manager::free_with_size,memory_manager::get_malloc_bytes,malloc::counted_malloc,malloc::counted_calloc,malloc::realloc_with_old_size,malloc::free_with_size… - count_live_bytes_in_gc
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Count the size of all live objects in GC
Affects
memory_manager::live_bytes_in_last_gc… - bpftrace_workaround
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Workaround a problem where bpftrace scripts (see tools/tracing/timeline/capture.bt) cannot capture the type names of work packets.
- malloc_mimalloc = mimalloc-sys
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Do not modify the following line - ci-common.sh matches it -- Mutally exclusive features --
Only one feature from each group can be provided. Otherwise build will fail.
Name of the mutualy exclusive feature group. ci-common.sh matches lines like this one.
Group:malloc
only one of the following features should be enabled, or none to use the default malloc from libc this does not replace the global Rust allocator, but provides these libraries for GC implementation - malloc_jemalloc = jemalloc-sys
- malloc_native_mimalloc
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Use the native mimalloc allocator for malloc. This is not tested by me (Yi) yet, and it is only used to make sure that some code is not compiled in default builds.
- eager_sweeping vo_bit?
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If there are more groups, they should be inserted above this line Group:end
Group:marksweepallocation
default is native allocator with lazy sweeping - malloc_mark_sweep
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Use library malloc as the freelist allocator for mark sweep. This will makes mark sweep slower. As malloc may return addresses outside our normal heap range, we will have to use chunk-based SFT table. Turning on this feature will use a different SFT map implementation on 64bits,
and will affect all the plans in the build. Please be aware of the consequence, and this is only meant to be experimental use.Affects
global::MarkSweepSpace…
Features from optional dependencies
In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.