Update to MMTk core PR #817

mmtk/Cargo.toml

@@ -28,7 +28,7 @@ log = {version = "0.4", features = ["max_level_trace", "release_max_level_off"]
 # - change branch/rev
 # - 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 = "e309f9351dff9cd0c8f3f590002c6edafd158c82" }
+mmtk = { git = "https://github.com/ArberSephirotheca/mmtk-core.git", rev = "1bd9b39053f5596204c196746f50a2dd51128c7c" }
 # Uncomment the following to build locally - if you change the path locally, do not commit the change in a PR
 # mmtk = { path = "../repos/mmtk-core" }
 

mmtk/src/active_plan.rs

@@ -6,28 +6,62 @@ use mmtk::vm::ActivePlan;
 use mmtk::Mutator;
 use mmtk::Plan;
 use std::mem;
-use std::sync::atomic::{AtomicUsize, Ordering};
 use JikesRVM;
 use JTOC_BASE;
 use SINGLETON;
 
-static MUTATOR_COUNTER: AtomicUsize = AtomicUsize::new(0);
+use std::sync::{Mutex, MutexGuard};
+
+lazy_static! {
+ static ref MUTATOR_LOCK: Mutex<()> = Mutex::new(());
+}
+
+struct JikesRVMMutatorIterator<'a> {
+ _guard: MutexGuard<'a, ()>,
+ counter: usize,
+}
+
+impl<'a> JikesRVMMutatorIterator<'a> {
+ fn new(guard: MutexGuard<'a, ()>) -> Self {
+ Self {
+ _guard: guard,
+ counter: 0,
+ }
+ }
+}
+
+impl<'a> Iterator for JikesRVMMutatorIterator<'a> {
+ type Item = &'a mut Mutator<JikesRVM>;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ // We don't need this in the loop for STW-GC
+ let num_threads = unsafe { (JTOC_BASE + NUM_THREADS_FIELD_OFFSET).load::<usize>() };
+ loop {
+ let idx = self.counter;
+ self.counter += 1;
+ if idx >= num_threads {
+ return None;
+ } else {
+ let t = unsafe { VMCollection::thread_from_index(idx) };
+ let is_mutator = unsafe { !(t + IS_COLLECTOR_FIELD_OFFSET).load::<bool>() };
+ if is_mutator {
+ unsafe {
+ let mutator = (t + MMTK_HANDLE_FIELD_OFFSET).load::<usize>();
+ let ret = &mut *(mutator as *mut Mutator<JikesRVM>);
+ return Some(ret);
+ }
+ }
+ }
+ }
+ }
+}
 
 #[derive(Default)]
 pub struct VMActivePlan {}
 
 impl ActivePlan<JikesRVM> for VMActivePlan {
  fn number_of_mutators() -> usize {
- let num_threads = unsafe { (JTOC_BASE + NUM_THREADS_FIELD_OFFSET).load::<usize>() };
- let mut num_mutators = 0usize;
- for idx in 0..num_threads {
- let t = unsafe { VMCollection::thread_from_index(idx) };
- let is_mutator = unsafe { !(t + IS_COLLECTOR_FIELD_OFFSET).load::<bool>() };
- if is_mutator {
- num_mutators += 1;
- }
- }
- num_mutators
+ Self::mutators().count()
  }
 
  fn global() -> &'static dyn Plan<VM = JikesRVM> {
@@ -48,28 +82,8 @@ impl ActivePlan<JikesRVM> for VMActivePlan {
  }
  }
 
- fn reset_mutator_iterator() {
- MUTATOR_COUNTER.store(0, Ordering::Relaxed);
- }
-
- fn get_next_mutator() -> Option<&'static mut Mutator<JikesRVM>> {
- // We don't need this in the loop for STW-GC
- let num_threads = unsafe { (JTOC_BASE + NUM_THREADS_FIELD_OFFSET).load::<usize>() };
- loop {
- let idx = MUTATOR_COUNTER.fetch_add(1, Ordering::Relaxed);
- if idx >= num_threads {
- return None;
- } else {
- let t = unsafe { VMCollection::thread_from_index(idx) };
- let is_mutator = unsafe { !(t + IS_COLLECTOR_FIELD_OFFSET).load::<bool>() };
- if is_mutator {
- unsafe {
- let mutator = (t + MMTK_HANDLE_FIELD_OFFSET).load::<usize>();
- let ret = &mut *(mutator as *mut Mutator<JikesRVM>);
- return Some(ret);
- }
- }
- }
- }
+ fn mutators<'a>() -> Box<dyn Iterator<Item = &'a mut Mutator<JikesRVM>> + 'a> {
+ let guard = MUTATOR_LOCK.lock().unwrap();
+ Box::new(JikesRVMMutatorIterator::new(guard))
  }
 }