Fix GC controller thread context

Following an upstream change, the GC controller thread now has a
context, too.

Author: wks

mmtk/Cargo.toml

@@ -20,9 +20,11 @@ lazy_static = "1.1"
 # - 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 = "4ebb6b68f54a55bf8794ea01db3f2d0f28d15f4d" }
+#mmtk = { git = "https://github.com/mmtk/mmtk-core.git", rev = "4ebb6b68f54a55bf8794ea01db3f2d0f28d15f4d" }
 # Uncomment the following to build locally
 # mmtk = { path = "../repos/mmtk-core" }
+mmtk = { git = "https://github.com/wks/mmtk-core.git", branch = "refactor-scheduler" }
+
 
 [features]
 default = []

mmtk/src/api.rs

@@ -5,6 +5,7 @@ use crate::UPCALLS;
 use libc::c_char;
 use mmtk::memory_manager;
 use mmtk::plan::BarrierSelector;
+use mmtk::scheduler::GCController;
 use mmtk::scheduler::GCWorker;
 use mmtk::util::alloc::AllocatorSelector;
 use mmtk::util::opaque_pointer::*;
@@ -50,8 +51,14 @@ pub extern "C" fn openjdk_gc_init(calls: *const OpenJDK_Upcalls, heap_size: usiz
 }
 
 #[no_mangle]
-pub extern "C" fn start_control_collector(tls: VMWorkerThread) {
-    memory_manager::start_control_collector(&SINGLETON, tls);
+// We trust the gc_collector pointer is valid.
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+pub extern "C" fn start_control_collector(
+    tls: VMWorkerThread,
+    gc_controller: *mut GCController<OpenJDK>,
+) {
+    let mut gc_controller = unsafe { Box::from_raw(gc_controller) };
+    memory_manager::start_control_collector(tls, &mut gc_controller, &SINGLETON);
 }
 
 #[no_mangle]

mmtk/src/collection.rs

@@ -1,7 +1,7 @@
-use mmtk::scheduler::{GCWorker, WorkBucketStage};
+use mmtk::scheduler::WorkBucketStage;
 use mmtk::scheduler::{ProcessEdgesWork, ScanStackRoot};
 use mmtk::util::opaque_pointer::*;
-use mmtk::vm::{Collection, Scanning, VMBinding};
+use mmtk::vm::{Collection, GCThreadContext, Scanning, VMBinding};
 use mmtk::{Mutator, MutatorContext};
 
 use crate::OpenJDK;
@@ -19,6 +19,9 @@ extern "C" fn create_mutator_scan_work<E: ProcessEdgesWork<VM = OpenJDK>>(
     );
 }
 
+const GC_THREAD_KIND_CONTROLLER: libc::c_int = 0;
+const GC_THREAD_KIND_WORKER: libc::c_int = 1;
+
 impl Collection<OpenJDK> for VMCollection {
     /// With the presence of the "VM companion thread",
     /// the OpenJDK binding allows any MMTk GC thread to stop/start the world.
@@ -49,14 +52,18 @@ impl Collection<OpenJDK> for VMCollection {
         }
     }
 
-    fn spawn_worker_thread(tls: VMThread, ctx: Option<Box<GCWorker<OpenJDK>>>) {
-        let ctx_ptr = if let Some(r) = ctx {
-            Box::into_raw(r)
-        } else {
-            std::ptr::null_mut()
+    fn spawn_gc_thread(tls: VMThread, ctx: GCThreadContext<OpenJDK>) {
+        let (ctx_ptr, kind) = match ctx {
+            GCThreadContext::Controller(c) => (
+                Box::into_raw(c) as *mut libc::c_void,
+                GC_THREAD_KIND_CONTROLLER,
+            ),
+            GCThreadContext::Worker(w) => {
+                (Box::into_raw(w) as *mut libc::c_void, GC_THREAD_KIND_WORKER)
+            }
         };
         unsafe {
-            ((*UPCALLS).spawn_worker_thread)(tls, ctx_ptr as usize as _);
+            ((*UPCALLS).spawn_gc_thread)(tls, kind, ctx_ptr);
         }
     }
 

mmtk/src/lib.rs

@@ -13,7 +13,6 @@ extern crate lazy_static;
 use std::ptr::null_mut;
 
 use libc::{c_char, c_void, uintptr_t};
-use mmtk::scheduler::GCWorker;
 use mmtk::util::opaque_pointer::*;
 use mmtk::util::{Address, ObjectReference};
 use mmtk::vm::VMBinding;
@@ -45,7 +44,7 @@ pub struct OpenJDK_Upcalls {
         create_stack_scan_work: *const extern "C" fn(&'static mut Mutator<OpenJDK>),
     ),
     pub resume_mutators: extern "C" fn(tls: VMWorkerThread),
-    pub spawn_worker_thread: extern "C" fn(tls: VMThread, ctx: *mut GCWorker<OpenJDK>),
+    pub spawn_gc_thread: extern "C" fn(tls: VMThread, kind: libc::c_int, ctx: *mut libc::c_void),
     pub block_for_gc: extern "C" fn(),
     pub get_next_mutator: extern "C" fn() -> *mut Mutator<OpenJDK>,
     pub reset_mutator_iterator: extern "C" fn(),

openjdk/mmtk.h

@@ -78,7 +78,7 @@ extern bool process_bulk(char* options);
 extern void scan_region();
 extern void handle_user_collection_request(void *tls);
 
-extern void start_control_collector(void *tls);
+extern void start_control_collector(void *tls, void *context);
 extern void start_worker(void *tls, void* worker);
 
 /**
@@ -100,7 +100,7 @@ typedef NewBuffer (*ProcessEdgesFn)(void** buf, size_t len, size_t cap);
 typedef struct {
     void (*stop_all_mutators) (void *tls, void (*create_stack_scan_work)(void* mutator));
     void (*resume_mutators) (void *tls);
-    void (*spawn_collector_thread) (void *tls, void *ctx);
+    void (*spawn_collector_thread) (void *tls, int kind, void *ctx);
     void (*block_for_gc) ();
     void* (*get_next_mutator) ();
     void (*reset_mutator_iterator) ();

openjdk/mmtkContextThread.cpp

@@ -26,11 +26,11 @@
 #include "mmtk.h"
 #include "mmtkContextThread.hpp"
 
-MMTkContextThread::MMTkContextThread() : NamedThread() {
+MMTkContextThread::MMTkContextThread(void *context) : NamedThread(), context_(context) {
   set_name("MMTk Controller Context Thread");
 }
 
 void MMTkContextThread::run() {
   this->initialize_named_thread();
-  start_control_collector((void*) this);
+  start_control_collector((void*) this, context_);
 }

openjdk/mmtkContextThread.hpp

@@ -29,9 +29,10 @@
 #include "runtime/thread.hpp"
 
 class MMTkContextThread: public NamedThread {
+  void* context_;
 public:
   // Constructor
-  MMTkContextThread();
+  MMTkContextThread(void* context);
 
   // No destruction allowed
   ~MMTkContextThread() {

openjdk/mmtkUpcalls.cpp

@@ -86,22 +86,33 @@ static void mmtk_resume_mutators(void *tls) {
   log_debug(gc)("Mutators notified.");
 }
 
-static void mmtk_spawn_collector_thread(void* tls, void* ctx) {
-  if (ctx == NULL) {
-    MMTkContextThread* t = new MMTkContextThread();
-    if (!os::create_thread(t, os::pgc_thread)) {
-      printf("Failed to create thread");
-      guarantee(false, "panic");
+static const int GC_THREAD_KIND_CONTROLLER = 0;
+static const int GC_THREAD_KIND_WORKER = 1;
+static void mmtk_spawn_collector_thread(void* tls, int kind, void* ctx) {
+  switch (kind) {
+    case GC_THREAD_KIND_CONTROLLER: {
+      MMTkContextThread* t = new MMTkContextThread(ctx);
+      if (!os::create_thread(t, os::pgc_thread)) {
+        printf("Failed to create thread");
+        guarantee(false, "panic");
+      }
+      os::start_thread(t);
+      break;
+    }
+    case GC_THREAD_KIND_WORKER: {
+      MMTkHeap::heap()->new_collector_thread();
+      MMTkCollectorThread* t = new MMTkCollectorThread(ctx);
+      if (!os::create_thread(t, os::pgc_thread)) {
+        printf("Failed to create thread");
+        guarantee(false, "panic");
+      }
+      os::start_thread(t);
+      break;
     }
-    os::start_thread(t);
-  } else {
-    MMTkHeap::heap()->new_collector_thread();
-    MMTkCollectorThread* t = new MMTkCollectorThread(ctx);
-    if (!os::create_thread(t, os::pgc_thread)) {
-      printf("Failed to create thread");
+    default: {
+      printf("Unexpected thread kind: %d\n", kind);
       guarantee(false, "panic");
     }
-    os::start_thread(t);
   }
 }