Merge pull request #1896 from meum/patch-1
[mono.git] / mono / sgen / sgen-gc.c
index 18960bbc1ca447786f2f24d84b13de226316ca37..b73c1d88ff1d2d1330fccfa95dd7c106ee86724c 100644 (file)
@@ -239,12 +239,6 @@ static gboolean do_concurrent_checks = FALSE;
    each collection */
 static gboolean do_scan_starts_check = FALSE;
 
-/*
- * If the major collector is concurrent and this is FALSE, we will
- * never initiate a synchronous major collection, unless requested via
- * GC.Collect().
- */
-static gboolean allow_synchronous_major = TRUE;
 static gboolean disable_minor_collections = FALSE;
 static gboolean disable_major_collections = FALSE;
 static gboolean do_verify_nursery = FALSE;
@@ -346,7 +340,7 @@ nursery_canaries_enabled (void)
  * ########  Global data.
  * ######################################################################
  */
-LOCK_DECLARE (gc_mutex);
+MonoCoopMutex gc_mutex;
 gboolean sgen_try_free_some_memory;
 
 #define SCAN_START_SIZE        SGEN_SCAN_START_SIZE
@@ -359,7 +353,7 @@ GCMemSection *nursery_section = NULL;
 static volatile mword lowest_heap_address = ~(mword)0;
 static volatile mword highest_heap_address = 0;
 
-LOCK_DECLARE (sgen_interruption_mutex);
+MonoCoopMutex sgen_interruption_mutex;
 
 int current_collection_generation = -1;
 static volatile gboolean concurrent_collection_in_progress = FALSE;
@@ -444,7 +438,7 @@ gray_queue_redirect (SgenGrayQueue *queue)
                GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
                if (!section)
                        break;
-               sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
+               sgen_section_gray_queue_enqueue ((SgenSectionGrayQueue *)queue->alloc_prepare_data, section);
                wake = TRUE;
        }
 
@@ -477,7 +471,7 @@ sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc
                }
 
                if (allow_flags) {
-                       if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
+                       if (!(obj = (char *)SGEN_OBJECT_IS_FORWARDED (start)))
                                obj = start;
                } else {
                        obj = start;
@@ -506,7 +500,7 @@ sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc
  * lock must be held.  For serial collectors that is not necessary.
  */
 void
-sgen_add_to_global_remset (gpointer ptr, gpointer obj)
+sgen_add_to_global_remset (gpointer ptr, GCObject *obj)
 {
        SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
 
@@ -539,30 +533,25 @@ sgen_add_to_global_remset (gpointer ptr, gpointer obj)
  * frequently after each object is copied, to achieve better locality and cache
  * usage.
  *
- * max_objs is the maximum number of objects to scan, or -1 to scan until the stack is
- * empty.
  */
 gboolean
-sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
+sgen_drain_gray_stack (ScanCopyContext ctx)
 {
        ScanObjectFunc scan_func = ctx.ops->scan_object;
        GrayQueue *queue = ctx.queue;
 
-       if (current_collection_generation == GENERATION_OLD && major_collector.drain_gray_stack)
-               return major_collector.drain_gray_stack (ctx);
+       if (ctx.ops->drain_gray_stack)
+               return ctx.ops->drain_gray_stack (queue);
 
-       do {
-               int i;
-               for (i = 0; i != max_objs; ++i) {
-                       GCObject *obj;
-                       SgenDescriptor desc;
-                       GRAY_OBJECT_DEQUEUE (queue, &obj, &desc);
-                       if (!obj)
-                               return TRUE;
-                       SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
-                       scan_func (obj, desc, queue);
-               }
-       } while (max_objs < 0);
+       for (;;) {
+               GCObject *obj;
+               SgenDescriptor desc;
+               GRAY_OBJECT_DEQUEUE (queue, &obj, &desc);
+               if (!obj)
+                       return TRUE;
+               SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
+               scan_func (obj, desc, queue);
+       }
        return FALSE;
 }
 
@@ -873,7 +862,7 @@ pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx)
        RootRecord *root;
        SGEN_LOG (2, "Scanning pinned roots (%d bytes, %d/%d entries)", (int)roots_size, roots_hash [ROOT_TYPE_NORMAL].num_entries, roots_hash [ROOT_TYPE_PINNED].num_entries);
        /* objects pinned from the API are inside these roots */
-       SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
+       SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], void **, start_root, RootRecord *, root) {
                SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
                sgen_conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
        } SGEN_HASH_TABLE_FOREACH_END;
@@ -890,7 +879,7 @@ pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx)
 static void
 single_arg_user_copy_or_mark (GCObject **obj, void *gc_data)
 {
-       ScanCopyContext *ctx = gc_data;
+       ScanCopyContext *ctx = (ScanCopyContext *)gc_data;
        ctx->ops->copy_or_mark_object (obj, ctx->queue);
 }
 
@@ -921,7 +910,7 @@ precisely_scan_objects_from (void** start_root, void** end_root, char* n_start,
                }
                return;
        case ROOT_DESC_COMPLEX: {
-               gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
+               gsize *bitmap_data = (gsize *)sgen_get_complex_descriptor_bitmap (desc);
                gsize bwords = (*bitmap_data) - 1;
                void **start_run = start_root;
                bitmap_data++;
@@ -997,21 +986,21 @@ alloc_nursery (void)
         * objects in the existing nursery.
         */
        /* FIXME: handle OOM */
-       section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
+       section = (GCMemSection *)sgen_alloc_internal (INTERNAL_MEM_SECTION);
 
        alloc_size = sgen_nursery_size;
 
        /* If there isn't enough space even for the nursery we should simply abort. */
        g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
 
-       data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
+       data = (char *)major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
        sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
        SGEN_LOG (4, "Expanding nursery size (%p-%p): %lu, total: %lu", data, data + alloc_size, (unsigned long)sgen_nursery_size, (unsigned long)sgen_gc_get_total_heap_allocation ());
        section->data = section->next_data = data;
        section->size = alloc_size;
        section->end_data = data + sgen_nursery_size;
        scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
-       section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
+       section->scan_starts = (char **)sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
        section->num_scan_start = scan_starts;
 
        nursery_section = section;
@@ -1033,7 +1022,7 @@ scan_finalizer_entries (SgenPointerQueue *fin_queue, ScanCopyContext ctx)
        size_t i;
 
        for (i = 0; i < fin_queue->next_slot; ++i) {
-               GCObject *obj = fin_queue->data [i];
+               GCObject *obj = (GCObject *)fin_queue->data [i];
                if (!obj)
                        continue;
                SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
@@ -1080,7 +1069,7 @@ finish_gray_stack (int generation, ScanCopyContext ctx)
         *   To achieve better cache locality and cache usage, we drain the gray stack 
         * frequently, after each object is copied, and just finish the work here.
         */
-       sgen_drain_gray_stack (-1, ctx);
+       sgen_drain_gray_stack (ctx);
        TV_GETTIME (atv);
        SGEN_LOG (2, "%s generation done", generation_name (generation));
 
@@ -1102,7 +1091,7 @@ finish_gray_stack (int generation, ScanCopyContext ctx)
        done_with_ephemerons = 0;
        do {
                done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
-               sgen_drain_gray_stack (-1, ctx);
+               sgen_drain_gray_stack (ctx);
                ++ephemeron_rounds;
        } while (!done_with_ephemerons);
 
@@ -1110,7 +1099,7 @@ finish_gray_stack (int generation, ScanCopyContext ctx)
 
        if (sgen_client_bridge_need_processing ()) {
                /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
-               sgen_drain_gray_stack (-1, ctx);
+               sgen_drain_gray_stack (ctx);
                sgen_collect_bridge_objects (generation, ctx);
                if (generation == GENERATION_OLD)
                        sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
@@ -1134,7 +1123,7 @@ finish_gray_stack (int generation, ScanCopyContext ctx)
        Make sure we drain the gray stack before processing disappearing links and finalizers.
        If we don't make sure it is empty we might wrongly see a live object as dead.
        */
-       sgen_drain_gray_stack (-1, ctx);
+       sgen_drain_gray_stack (ctx);
 
        /*
        We must clear weak links that don't track resurrection before processing object ready for
@@ -1155,7 +1144,7 @@ finish_gray_stack (int generation, ScanCopyContext ctx)
                sgen_finalize_in_range (GENERATION_NURSERY, ctx);
        /* drain the new stack that might have been created */
        SGEN_LOG (6, "Precise scan of gray area post fin");
-       sgen_drain_gray_stack (-1, ctx);
+       sgen_drain_gray_stack (ctx);
 
        /*
         * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
@@ -1163,7 +1152,7 @@ finish_gray_stack (int generation, ScanCopyContext ctx)
        done_with_ephemerons = 0;
        do {
                done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
-               sgen_drain_gray_stack (-1, ctx);
+               sgen_drain_gray_stack (ctx);
                ++ephemeron_rounds;
        } while (!done_with_ephemerons);
 
@@ -1194,7 +1183,7 @@ finish_gray_stack (int generation, ScanCopyContext ctx)
                        sgen_null_link_in_range (GENERATION_NURSERY, ctx, TRUE);
                if (sgen_gray_object_queue_is_empty (queue))
                        break;
-               sgen_drain_gray_stack (-1, ctx);
+               sgen_drain_gray_stack (ctx);
        }
 
        g_assert (sgen_gray_object_queue_is_empty (queue));
@@ -1228,7 +1217,7 @@ scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, Sca
 {
        void **start_root;
        RootRecord *root;
-       SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
+       SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], void **, start_root, RootRecord *, root) {
                SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
                precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
        } SGEN_HASH_TABLE_FOREACH_END;
@@ -1336,7 +1325,7 @@ typedef struct {
 static void
 job_remembered_set_scan (void *worker_data_untyped, SgenThreadPoolJob *job)
 {
-       WorkerData *worker_data = worker_data_untyped;
+       WorkerData *worker_data = (WorkerData *)worker_data_untyped;
        ScanJob *job_data = (ScanJob*)job;
        ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
        remset.scan_remsets (ctx);
@@ -1353,7 +1342,7 @@ typedef struct {
 static void
 job_scan_from_registered_roots (void *worker_data_untyped, SgenThreadPoolJob *job)
 {
-       WorkerData *worker_data = worker_data_untyped;
+       WorkerData *worker_data = (WorkerData *)worker_data_untyped;
        ScanFromRegisteredRootsJob *job_data = (ScanFromRegisteredRootsJob*)job;
        ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
 
@@ -1370,7 +1359,7 @@ typedef struct {
 static void
 job_scan_thread_data (void *worker_data_untyped, SgenThreadPoolJob *job)
 {
-       WorkerData *worker_data = worker_data_untyped;
+       WorkerData *worker_data = (WorkerData *)worker_data_untyped;
        ScanThreadDataJob *job_data = (ScanThreadDataJob*)job;
        ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
 
@@ -1386,7 +1375,7 @@ typedef struct {
 static void
 job_scan_finalizer_entries (void *worker_data_untyped, SgenThreadPoolJob *job)
 {
-       WorkerData *worker_data = worker_data_untyped;
+       WorkerData *worker_data = (WorkerData *)worker_data_untyped;
        ScanFinalizerEntriesJob *job_data = (ScanFinalizerEntriesJob*)job;
        ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
 
@@ -1396,7 +1385,7 @@ job_scan_finalizer_entries (void *worker_data_untyped, SgenThreadPoolJob *job)
 static void
 job_scan_major_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
 {
-       WorkerData *worker_data = worker_data_untyped;
+       WorkerData *worker_data = (WorkerData *)worker_data_untyped;
        ScanJob *job_data = (ScanJob*)job;
        ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
 
@@ -1407,7 +1396,7 @@ job_scan_major_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJo
 static void
 job_scan_los_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
 {
-       WorkerData *worker_data = worker_data_untyped;
+       WorkerData *worker_data = (WorkerData *)worker_data_untyped;
        ScanJob *job_data = (ScanJob*)job;
        ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
 
@@ -1416,15 +1405,15 @@ job_scan_los_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob
 }
 
 static void
-init_gray_queue (void)
+init_gray_queue (gboolean use_workers)
 {
-       if (sgen_collection_is_concurrent ())
+       if (use_workers)
                sgen_workers_init_distribute_gray_queue ();
        sgen_gray_object_queue_init (&gray_queue, NULL);
 }
 
 static void
-enqueue_scan_from_roots_jobs (char *heap_start, char *heap_end, SgenObjectOperations *ops)
+enqueue_scan_from_roots_jobs (char *heap_start, char *heap_end, SgenObjectOperations *ops, gboolean enqueue)
 {
        ScanFromRegisteredRootsJob *scrrj;
        ScanThreadDataJob *stdj;
@@ -1437,33 +1426,33 @@ enqueue_scan_from_roots_jobs (char *heap_start, char *heap_end, SgenObjectOperat
        scrrj->heap_start = heap_start;
        scrrj->heap_end = heap_end;
        scrrj->root_type = ROOT_TYPE_NORMAL;
-       sgen_workers_enqueue_job (&scrrj->job);
+       sgen_workers_enqueue_job (&scrrj->job, enqueue);
 
        scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots wbarrier", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
        scrrj->ops = ops;
        scrrj->heap_start = heap_start;
        scrrj->heap_end = heap_end;
        scrrj->root_type = ROOT_TYPE_WBARRIER;
-       sgen_workers_enqueue_job (&scrrj->job);
+       sgen_workers_enqueue_job (&scrrj->job, enqueue);
 
        /* Threads */
 
        stdj = (ScanThreadDataJob*)sgen_thread_pool_job_alloc ("scan thread data", job_scan_thread_data, sizeof (ScanThreadDataJob));
        stdj->heap_start = heap_start;
        stdj->heap_end = heap_end;
-       sgen_workers_enqueue_job (&stdj->job);
+       sgen_workers_enqueue_job (&stdj->job, enqueue);
 
        /* Scan the list of objects ready for finalization. */
 
        sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
        sfej->queue = &fin_ready_queue;
        sfej->ops = ops;
-       sgen_workers_enqueue_job (&sfej->job);
+       sgen_workers_enqueue_job (&sfej->job, enqueue);
 
        sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan critical finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
        sfej->queue = &critical_fin_queue;
        sfej->ops = ops;
-       sgen_workers_enqueue_job (&sfej->job);
+       sgen_workers_enqueue_job (&sfej->job, enqueue);
 }
 
 /*
@@ -1527,7 +1516,7 @@ collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
 
        sgen_memgov_minor_collection_start ();
 
-       init_gray_queue ();
+       init_gray_queue (FALSE);
 
        gc_stats.minor_gc_count ++;
 
@@ -1565,7 +1554,7 @@ collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
         */
        sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan remset", job_remembered_set_scan, sizeof (ScanJob));
        sj->ops = object_ops;
-       sgen_workers_enqueue_job (&sj->job);
+       sgen_workers_enqueue_job (&sj->job, FALSE);
 
        /* we don't have complete write barrier yet, so we scan all the old generation sections */
        TV_GETTIME (btv);
@@ -1574,7 +1563,7 @@ collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
 
        sgen_pin_stats_print_class_stats ();
 
-       sgen_drain_gray_stack (-1, ctx);
+       sgen_drain_gray_stack (ctx);
 
        /* FIXME: Why do we do this at this specific, seemingly random, point? */
        sgen_client_collecting_minor (&fin_ready_queue, &critical_fin_queue);
@@ -1582,7 +1571,7 @@ collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
        TV_GETTIME (atv);
        time_minor_scan_pinned += TV_ELAPSED (btv, atv);
 
-       enqueue_scan_from_roots_jobs (sgen_get_nursery_start (), nursery_next, object_ops);
+       enqueue_scan_from_roots_jobs (sgen_get_nursery_start (), nursery_next, object_ops, FALSE);
 
        TV_GETTIME (btv);
        time_minor_scan_roots += TV_ELAPSED (atv, btv);
@@ -1691,7 +1680,7 @@ major_copy_or_mark_from_roots (size_t *old_next_pin_slot, CopyOrMarkFromRootsMod
                sgen_nursery_alloc_prepare_for_major ();
        }
 
-       init_gray_queue ();
+       init_gray_queue (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT);
 
        TV_GETTIME (atv);
 
@@ -1789,10 +1778,15 @@ major_copy_or_mark_from_roots (size_t *old_next_pin_slot, CopyOrMarkFromRootsMod
         * before pinning has finished.  For the non-concurrent
         * collector we start the workers after pinning.
         */
-       if (mode != COPY_OR_MARK_FROM_ROOTS_SERIAL) {
+       if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
                SGEN_ASSERT (0, sgen_workers_all_done (), "Why are the workers not done when we start or finish a major collection?");
                sgen_workers_start_all_workers (object_ops);
                gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
+       } else if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
+               if (sgen_workers_have_idle_work ()) {
+                       sgen_workers_start_all_workers (object_ops);
+                       sgen_workers_join ();
+               }
        }
 
 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
@@ -1810,7 +1804,7 @@ major_copy_or_mark_from_roots (size_t *old_next_pin_slot, CopyOrMarkFromRootsMod
         * FIXME: is this the right context?  It doesn't seem to contain a copy function
         * unless we're concurrent.
         */
-       enqueue_scan_from_roots_jobs (heap_start, heap_end, object_ops);
+       enqueue_scan_from_roots_jobs (heap_start, heap_end, object_ops, mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT);
 
        TV_GETTIME (btv);
        time_major_scan_roots += TV_ELAPSED (atv, btv);
@@ -1821,11 +1815,11 @@ major_copy_or_mark_from_roots (size_t *old_next_pin_slot, CopyOrMarkFromRootsMod
                /* Mod union card table */
                sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan mod union cardtable", job_scan_major_mod_union_card_table, sizeof (ScanJob));
                sj->ops = object_ops;
-               sgen_workers_enqueue_job (&sj->job);
+               sgen_workers_enqueue_job (&sj->job, FALSE);
 
                sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan LOS mod union cardtable", job_scan_los_mod_union_card_table, sizeof (ScanJob));
                sj->ops = object_ops;
-               sgen_workers_enqueue_job (&sj->job);
+               sgen_workers_enqueue_job (&sj->job, FALSE);
 
                TV_GETTIME (atv);
                time_major_scan_mod_union += TV_ELAPSED (btv, atv);
@@ -1837,8 +1831,7 @@ major_copy_or_mark_from_roots (size_t *old_next_pin_slot, CopyOrMarkFromRootsMod
 static void
 major_finish_copy_or_mark (CopyOrMarkFromRootsMode mode)
 {
-       switch (mode) {
-       case COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT:
+       if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
                /*
                 * Prepare the pin queue for the next collection.  Since pinning runs on the worker
                 * threads we must wait for the jobs to finish before we can reset it.
@@ -1850,14 +1843,6 @@ major_finish_copy_or_mark (CopyOrMarkFromRootsMode mode)
 
                if (do_concurrent_checks)
                        sgen_debug_check_nursery_is_clean ();
-               break;
-       case COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT:
-               sgen_workers_wait_for_jobs_finished ();
-               break;
-       case COPY_OR_MARK_FROM_ROOTS_SERIAL:
-               break;
-       default:
-               g_assert_not_reached ();
        }
 }
 
@@ -1922,10 +1907,6 @@ major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean
 
                major_finish_copy_or_mark (COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT);
 
-               sgen_workers_join ();
-
-               SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty after workers have finished working?");
-
 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
                main_gc_thread = NULL;
 #endif
@@ -1933,12 +1914,6 @@ major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean
                object_ops = &major_collector.major_ops_serial;
        }
 
-       /*
-        * The workers have stopped so we need to finish gray queue
-        * work that might result from finalization in the main GC
-        * thread.  Redirection must therefore be turned off.
-        */
-       sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
        g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
 
        /* all the objects in the heap */
@@ -2148,12 +2123,11 @@ major_finish_concurrent_collection (gboolean forced)
        binary_protocol_concurrent_finish ();
 
        /*
-        * The major collector can add global remsets which are processed in the finishing
-        * nursery collection, below.  That implies that the workers must have finished
-        * marking before the nursery collection is allowed to run, otherwise we might miss
-        * some remsets.
+        * We need to stop all workers since we're updating the cardtable below.
+        * The workers will be resumed with a finishing pause context to avoid
+        * additional cardtable and object scanning.
         */
-       sgen_workers_wait ();
+       sgen_workers_stop_all_workers ();
 
        SGEN_TV_GETTIME (time_major_conc_collection_end);
        gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
@@ -2200,7 +2174,7 @@ sgen_ensure_free_space (size_t size)
                                generation_to_collect = GENERATION_OLD;
                        }
                } else if (sgen_need_major_collection (size)) {
-                       reason = "Minor allowance";
+                       reason = concurrent_collection_in_progress ? "Forced finish concurrent collection" : "Minor allowance";
                        generation_to_collect = GENERATION_OLD;
                } else {
                        generation_to_collect = GENERATION_NURSERY;
@@ -2247,34 +2221,23 @@ sgen_perform_collection (size_t requested_size, int generation_to_collect, const
 
        if (concurrent_collection_in_progress) {
                /*
-                * We update the concurrent collection.  If it finished, we're done.  If
-                * not, and we've been asked to do a nursery collection, we do that.
+                * If the concurrent worker is finished or we are asked to do a major collection
+                * then we finish the concurrent collection.
                 */
-               gboolean finish = major_should_finish_concurrent_collection () || (wait_to_finish && generation_to_collect == GENERATION_OLD);
+               gboolean finish = major_should_finish_concurrent_collection () || generation_to_collect == GENERATION_OLD;
 
                if (finish) {
                        major_finish_concurrent_collection (wait_to_finish);
                        oldest_generation_collected = GENERATION_OLD;
                } else {
+                       SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY, "Why aren't we finishing the concurrent collection?");
                        major_update_concurrent_collection ();
-                       if (generation_to_collect == GENERATION_NURSERY)
-                               collect_nursery (NULL, FALSE);
+                       collect_nursery (NULL, FALSE);
                }
 
                goto done;
        }
 
-       /*
-        * If we've been asked to do a major collection, and the major collector wants to
-        * run synchronously (to evacuate), we set the flag to do that.
-        */
-       if (generation_to_collect == GENERATION_OLD &&
-                       allow_synchronous_major &&
-                       major_collector.want_synchronous_collection &&
-                       *major_collector.want_synchronous_collection) {
-               wait_to_finish = TRUE;
-       }
-
        SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
 
        /*
@@ -2469,11 +2432,11 @@ sgen_gc_invoke_finalizers (void)
                if (!sgen_pointer_queue_is_empty (&fin_ready_queue)) {
                        pending_unqueued_finalizer = TRUE;
                        mono_memory_write_barrier ();
-                       obj = sgen_pointer_queue_pop (&fin_ready_queue);
+                       obj = (GCObject *)sgen_pointer_queue_pop (&fin_ready_queue);
                } else if (!sgen_pointer_queue_is_empty (&critical_fin_queue)) {
                        pending_unqueued_finalizer = TRUE;
                        mono_memory_write_barrier ();
-                       obj = sgen_pointer_queue_pop (&critical_fin_queue);
+                       obj = (GCObject *)sgen_pointer_queue_pop (&critical_fin_queue);
                } else {
                        obj = NULL;
                }
@@ -2522,7 +2485,7 @@ sgen_register_root (char *start, size_t size, SgenDescriptor descr, int root_typ
        int i;
        LOCK_GC;
        for (i = 0; i < ROOT_TYPE_NUM; ++i) {
-               RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
+               RootRecord *root = (RootRecord *)sgen_hash_table_lookup (&roots_hash [i], start);
                /* we allow changing the size and the descriptor (for thread statics etc) */
                if (root) {
                        size_t old_size = root->end_root - start;
@@ -2683,7 +2646,7 @@ mono_gc_wbarrier_generic_store_atomic (gpointer ptr, GCObject *value)
 
        SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
 
-       InterlockedWritePointer (ptr, value);
+       InterlockedWritePointer ((volatile gpointer *)ptr, value);
 
        if (ptr_in_nursery (value) || concurrent_collection_in_progress)
                mono_gc_wbarrier_generic_nostore (ptr);
@@ -2694,8 +2657,8 @@ mono_gc_wbarrier_generic_store_atomic (gpointer ptr, GCObject *value)
 void
 sgen_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
 {
-       GCObject **dest = _dest;
-       GCObject **src = _src;
+       GCObject **dest = (GCObject **)_dest;
+       GCObject **src = (GCObject **)_src;
 
        while (size) {
                if (bitmap & 0x1)
@@ -2746,16 +2709,6 @@ sgen_gc_get_used_size (void)
        return tot;
 }
 
-gboolean
-sgen_set_allow_synchronous_major (gboolean flag)
-{
-       if (!major_collector.is_concurrent)
-               return flag;
-
-       allow_synchronous_major = flag;
-       return TRUE;
-}
-
 void
 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
 {
@@ -2827,11 +2780,11 @@ sgen_gc_init (void)
        mono_thread_smr_init ();
 #endif
 
-       LOCK_INIT (gc_mutex);
+       mono_coop_mutex_init (&gc_mutex);
 
        gc_debug_file = stderr;
 
-       LOCK_INIT (sgen_interruption_mutex);
+       mono_coop_mutex_init (&sgen_interruption_mutex);
 
        if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
                opts = g_strsplit (env, ",", -1);
@@ -2972,23 +2925,6 @@ sgen_gc_init (void)
                                }
                                continue;
                        }
-                       if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
-                               if (!major_collector.is_concurrent) {
-                                       sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
-                                       continue;
-                               }
-
-                               opt = strchr (opt, '=') + 1;
-
-                               if (!strcmp (opt, "yes")) {
-                                       allow_synchronous_major = TRUE;
-                               } else if (!strcmp (opt, "no")) {
-                                       allow_synchronous_major = FALSE;
-                               } else {
-                                       sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
-                                       continue;
-                               }
-                       }
 
                        if (!strcmp (opt, "cementing")) {
                                cement_enabled = TRUE;
@@ -3021,8 +2957,6 @@ sgen_gc_init (void)
                        fprintf (stderr, "  minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
                        fprintf (stderr, "  wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
                        fprintf (stderr, "  [no-]cementing\n");
-                       if (major_collector.is_concurrent)
-                               fprintf (stderr, "  allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
                        if (major_collector.print_gc_param_usage)
                                major_collector.print_gc_param_usage ();
                        if (sgen_minor_collector.print_gc_param_usage)
@@ -3133,7 +3067,7 @@ sgen_gc_init (void)
                        } else if (g_str_has_prefix (opt, "binary-protocol=")) {
                                char *filename = strchr (opt, '=') + 1;
                                char *colon = strrchr (filename, ':');
-                               size_t limit = -1;
+                               size_t limit = 0;
                                if (colon) {
                                        if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
                                                sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
@@ -3211,7 +3145,7 @@ sgen_get_nursery_clear_policy (void)
 void
 sgen_gc_lock (void)
 {
-       LOCK_GC;
+       mono_coop_mutex_lock (&gc_mutex);
 }
 
 void
@@ -3219,7 +3153,7 @@ sgen_gc_unlock (void)
 {
        gboolean try_free = sgen_try_free_some_memory;
        sgen_try_free_some_memory = FALSE;
-       mono_mutex_unlock (&gc_mutex);
+       mono_coop_mutex_unlock (&gc_mutex);
        if (try_free)
                mono_thread_hazardous_try_free_some ();
 }