Pass hotspot command line flags to mmtk-core (#229)

* Pass hotspot cmdline flags to mmtk

* lower hotspot flag priority

* Remove println

* Use typed setter

* Update mmtk-core

Author: wenyuzhao

mmtk/Cargo.lock

@@ -30,7 +30,7 @@ once_cell = "1.10.0"
 # - change branch
 # - change repo name
 # But other changes including adding/removing whitespaces in commented lines may break the CI.
-mmtk = { git = "https://github.com/mmtk/mmtk-core.git", rev = "04a47feb4598b2120598453c2cceec83986c2122" }
+mmtk = { git = "https://github.com/mmtk/mmtk-core.git", rev = "4873b4ab4016a2a5ef413463443856efa373e90c" }
 # Uncomment the following to build locally
 # mmtk = { path = "../repos/mmtk-core" }
 

mmtk/Cargo.toml

@@ -290,6 +290,20 @@ pub extern "C" fn process(name: *const c_char, value: *const c_char) -> bool {
     )
 }
 
+/// Pass hotspot `ParallelGCThreads` flag to mmtk
+#[no_mangle]
+pub extern "C" fn mmtk_builder_set_threads(value: usize) {
+    let mut builder = BUILDER.lock().unwrap();
+    builder.options.threads.set(value);
+}
+
+/// Pass hotspot `UseTransparentHugePages` flag to mmtk
+#[no_mangle]
+pub extern "C" fn mmtk_builder_set_transparent_hugepages(value: bool) {
+    let mut builder = BUILDER.lock().unwrap();
+    builder.options.transparent_hugepages.set(value);
+}
+
 #[no_mangle]
 // We trust the name/value pointer is valid.
 #[allow(clippy::not_unsafe_ptr_arg_deref)]

mmtk/src/api.rs

@@ -211,6 +211,9 @@ extern void add_phantom_candidate(void* ref, void* referent);
 extern void mmtk_harness_begin_impl();
 extern void mmtk_harness_end_impl();
 
+extern void mmtk_builder_set_threads(size_t value);
+extern void mmtk_builder_set_transparent_hugepages(bool value);
+
 #ifdef __cplusplus
 }
 #endif

openjdk/mmtk.h

@@ -84,6 +84,8 @@ jint MMTkHeap::initialize() {
   //  printf("policy max heap size %zu, min heap size %zu\n", heap_size, collector_policy()->min_heap_byte_size());
 
   // Set options
+  mmtk_builder_set_threads(ParallelGCThreads);
+  mmtk_builder_set_transparent_hugepages(UseTransparentHugePages);
   if (ThirdPartyHeapOptions != NULL) {
     bool set_options = process_bulk(strdup(ThirdPartyHeapOptions));
     guarantee(set_options, "Failed to set MMTk options. Please check if the options are valid: %s\n", ThirdPartyHeapOptions);

openjdk/mmtkHeap.cpp

@@ -45,6 +45,12 @@ void ThirdPartyHeapArguments::initialize() {
   FLAG_SET_DEFAULT(UseTLAB, false);
   FLAG_SET_DEFAULT(UseCompressedOops, false);
   FLAG_SET_DEFAULT(UseCompressedClassPointers, false);
+  FLAG_SET_DEFAULT(ParallelGCThreads, Abstract_VM_Version::parallel_worker_threads());
+  if (ParallelGCThreads == 0) {
+    assert(!FLAG_IS_DEFAULT(ParallelGCThreads), "ParallelGCThreads should not be 0.");
+    vm_exit_during_initialization("The flag -XX:+UseUseThirdPartyHeap can not be combined with -XX:ParallelGCThreads=0", NULL);
+  }
+  
 }
 
 CollectedHeap* ThirdPartyHeapArguments::create_heap() {