Merge remote-tracking branch 'mfoliveira/ppc64el-v2'
[mono.git] / mono / metadata / sgen-marksweep.c
index d3093385805edaa25a5ff909771384024d13818b..88664226b9abdcec1108362a26abe1f9a24b2525 100644 (file)
 #include "metadata/sgen-memory-governor.h"
 #include "metadata/sgen-layout-stats.h"
 #include "metadata/gc-internal.h"
+#include "metadata/sgen-pointer-queue.h"
+#include "metadata/sgen-pinning.h"
+#include "metadata/sgen-workers.h"
 
-#if !defined(SGEN_PARALLEL_MARK) && !defined(FIXED_HEAP)
 #define SGEN_HAVE_CONCURRENT_MARK
-#endif
 
-#define MS_BLOCK_SIZE  (16*1024)
-#define MS_BLOCK_SIZE_SHIFT    14
+#if defined(ARCH_MIN_MS_BLOCK_SIZE) && defined(ARCH_MIN_MS_BLOCK_SIZE_SHIFT)
+#define MS_BLOCK_SIZE  ARCH_MIN_MS_BLOCK_SIZE
+#define MS_BLOCK_SIZE_SHIFT    ARCH_MIN_MS_BLOCK_SIZE_SHIFT
+#else
+#define MS_BLOCK_SIZE_SHIFT     14      /* INT FASTENABLE */
+#define MS_BLOCK_SIZE           (1 << MS_BLOCK_SIZE_SHIFT)
+#endif
 #define MAJOR_SECTION_SIZE     MS_BLOCK_SIZE
 #define CARDS_PER_BLOCK (MS_BLOCK_SIZE / CARD_SIZE_IN_BYTES)
 
-#ifdef FIXED_HEAP
-#define MS_DEFAULT_HEAP_NUM_BLOCKS     (32 * 1024) /* 512 MB */
-#endif
-
 /*
  * Don't allocate single blocks, but alloc a contingent of this many
  * blocks in one swoop.  This must be a power of two.
  * of a block is the MSBlockHeader, then opional padding, then come
  * the objects, so this must be >= sizeof (MSBlockHeader).
  */
-#ifdef FIXED_HEAP
-#define MS_BLOCK_SKIP  0
-#else
-#define MS_BLOCK_SKIP  16
-#endif
+#define MS_BLOCK_SKIP  ((sizeof (MSBlockHeader) + 15) & ~15)
 
 #define MS_BLOCK_FREE  (MS_BLOCK_SIZE - MS_BLOCK_SKIP)
 
 #define MS_NUM_MARK_WORDS      ((MS_BLOCK_SIZE / SGEN_ALLOC_ALIGN + sizeof (mword) * 8 - 1) / (sizeof (mword) * 8))
 
-#if SGEN_MAX_SMALL_OBJ_SIZE > MS_BLOCK_FREE / 2
-#error MAX_SMALL_OBJ_SIZE must be at most MS_BLOCK_FREE / 2
-#endif
-
 typedef struct _MSBlockInfo MSBlockInfo;
 struct _MSBlockInfo {
        int obj_size;
        int obj_size_index;
-       size_t pin_queue_num_entries;
        unsigned int pinned : 1;
        unsigned int has_references : 1;
        unsigned int has_pinned : 1;    /* means cannot evacuate */
        unsigned int is_to_space : 1;
        unsigned int swept : 1;
-#ifdef FIXED_HEAP
-       unsigned int used : 1;
-       unsigned int zeroed : 1;
-#endif
-       MSBlockInfo *next;
-       char *block;
        void **free_list;
        MSBlockInfo *next_free;
-       void **pin_queue_start;
+       size_t pin_queue_first_entry;
+       size_t pin_queue_last_entry;
 #ifdef SGEN_HAVE_CONCURRENT_MARK
        guint8 *cardtable_mod_union;
 #endif
        mword mark_words [MS_NUM_MARK_WORDS];
 };
 
-#ifdef FIXED_HEAP
-static mword ms_heap_num_blocks = MS_DEFAULT_HEAP_NUM_BLOCKS;
+#define MS_BLOCK_FOR_BLOCK_INFO(b)     ((char*)(b))
 
-static char *ms_heap_start;
-static char *ms_heap_end;
-
-#define MS_PTR_IN_SMALL_MAJOR_HEAP(p)  ((char*)(p) >= ms_heap_start && (char*)(p) < ms_heap_end)
-
-/* array of all all block infos in the system */
-static MSBlockInfo *block_infos;
-#endif
-
-#define MS_BLOCK_OBJ(b,i)              ((b)->block + MS_BLOCK_SKIP + (b)->obj_size * (i))
-#define MS_BLOCK_OBJ_FOR_SIZE(b,i,obj_size)            ((b)->block + MS_BLOCK_SKIP + (obj_size) * (i))
+#define MS_BLOCK_OBJ(b,i)              (MS_BLOCK_FOR_BLOCK_INFO(b) + MS_BLOCK_SKIP + (b)->obj_size * (i))
+#define MS_BLOCK_OBJ_FOR_SIZE(b,i,obj_size)            (MS_BLOCK_FOR_BLOCK_INFO(b) + MS_BLOCK_SKIP + (obj_size) * (i))
 #define MS_BLOCK_DATA_FOR_OBJ(o)       ((char*)((mword)(o) & ~(mword)(MS_BLOCK_SIZE - 1)))
 
-#ifdef FIXED_HEAP
-#define MS_BLOCK_FOR_OBJ(o)            (&block_infos [(mword)((char*)(o) - ms_heap_start) >> MS_BLOCK_SIZE_SHIFT])
-#else
 typedef struct {
-       MSBlockInfo *info;
+       MSBlockInfo info;
 } MSBlockHeader;
 
-#define MS_BLOCK_FOR_OBJ(o)            (((MSBlockHeader*)MS_BLOCK_DATA_FOR_OBJ ((o)))->info)
-#endif
+#define MS_BLOCK_FOR_OBJ(o)            (&((MSBlockHeader*)MS_BLOCK_DATA_FOR_OBJ ((o)))->info)
 
 /* object index will always be small */
-#define MS_BLOCK_OBJ_INDEX(o,b)        ((int)(((char*)(o) - ((b)->block + MS_BLOCK_SKIP)) / (b)->obj_size))
+#define MS_BLOCK_OBJ_INDEX(o,b)        ((int)(((char*)(o) - (MS_BLOCK_FOR_BLOCK_INFO(b) + MS_BLOCK_SKIP)) / (b)->obj_size))
 
 //casting to int is fine since blocks are 32k
 #define MS_CALC_MARK_BIT(w,b,o)        do {                            \
@@ -147,25 +121,10 @@ typedef struct {
 
 #define MS_MARK_BIT(bl,w,b)    ((bl)->mark_words [(w)] & (ONE_P << (b)))
 #define MS_SET_MARK_BIT(bl,w,b)        ((bl)->mark_words [(w)] |= (ONE_P << (b)))
-#define MS_PAR_SET_MARK_BIT(was_marked,bl,w,b) do {                    \
-               mword __old = (bl)->mark_words [(w)];                   \
-               mword __bitmask = ONE_P << (b);                         \
-               if (__old & __bitmask) {                                \
-                       was_marked = TRUE;                              \
-                       break;                                          \
-               }                                                       \
-               if (SGEN_CAS_PTR ((gpointer*)&(bl)->mark_words [(w)],   \
-                                               (gpointer)(__old | __bitmask), \
-                                               (gpointer)__old) ==     \
-                               (gpointer)__old) {                      \
-                       was_marked = FALSE;                             \
-                       break;                                          \
-               }                                                       \
-       } while (1)
 
-#define MS_OBJ_ALLOCED(o,b)    (*(void**)(o) && (*(char**)(o) < (b)->block || *(char**)(o) >= (b)->block + MS_BLOCK_SIZE))
+#define MS_OBJ_ALLOCED(o,b)    (*(void**)(o) && (*(char**)(o) < MS_BLOCK_FOR_BLOCK_INFO (b) || *(char**)(o) >= MS_BLOCK_FOR_BLOCK_INFO (b) + MS_BLOCK_SIZE))
 
-#define MS_BLOCK_OBJ_SIZE_FACTOR       (sqrt (2.0))
+#define MS_BLOCK_OBJ_SIZE_FACTOR       (pow (2.0, 1.0 / 3))
 
 /*
  * This way we can lookup block object size indexes for sizes up to
@@ -182,12 +141,6 @@ static int fast_block_obj_size_indexes [MS_NUM_FAST_BLOCK_OBJ_SIZE_INDEXES];
 
 #define MS_BLOCK_TYPE_MAX      4
 
-#ifdef SGEN_PARALLEL_MARK
-static LOCK_DECLARE (ms_block_list_mutex);
-#define LOCK_MS_BLOCK_LIST mono_mutex_lock (&ms_block_list_mutex)
-#define UNLOCK_MS_BLOCK_LIST mono_mutex_unlock (&ms_block_list_mutex)
-#endif
-
 static gboolean *evacuate_block_obj_sizes;
 static float evacuation_threshold = 0.666f;
 #ifdef SGEN_HAVE_CONCURRENT_MARK
@@ -202,52 +155,63 @@ static gboolean have_swept;
 static gboolean concurrent_mark;
 #endif
 
+#define BLOCK_IS_TAGGED_HAS_REFERENCES(bl)     SGEN_POINTER_IS_TAGGED_1 ((bl))
+#define BLOCK_TAG_HAS_REFERENCES(bl)           SGEN_POINTER_TAG_1 ((bl))
+#define BLOCK_UNTAG_HAS_REFERENCES(bl)         SGEN_POINTER_UNTAG_1 ((bl))
+
+#define BLOCK_TAG(bl)  ((bl)->has_references ? BLOCK_TAG_HAS_REFERENCES ((bl)) : (bl))
+
 /* all allocated blocks in the system */
-static MSBlockInfo *all_blocks;
+static SgenPointerQueue allocated_blocks;
 
-#ifdef FIXED_HEAP
-/* non-allocated block free-list */
-static MSBlockInfo *empty_blocks = NULL;
-#else
 /* non-allocated block free-list */
 static void *empty_blocks = NULL;
 static size_t num_empty_blocks = 0;
-#endif
 
-#define FOREACH_BLOCK(bl)      for ((bl) = all_blocks; (bl); (bl) = (bl)->next) {
-#define END_FOREACH_BLOCK      }
+#define FOREACH_BLOCK(bl)      { size_t __index; for (__index = 0; __index < allocated_blocks.next_slot; ++__index) { (bl) = BLOCK_UNTAG_HAS_REFERENCES (allocated_blocks.data [__index]);
+#define FOREACH_BLOCK_HAS_REFERENCES(bl,hr)    { size_t __index; for (__index = 0; __index < allocated_blocks.next_slot; ++__index) { (bl) = allocated_blocks.data [__index]; (hr) = BLOCK_IS_TAGGED_HAS_REFERENCES ((bl)); (bl) = BLOCK_UNTAG_HAS_REFERENCES ((bl));
+#define END_FOREACH_BLOCK      } }
+#define DELETE_BLOCK_IN_FOREACH()      (allocated_blocks.data [__index] = NULL)
 
 static size_t num_major_sections = 0;
 /* one free block list for each block object size */
 static MSBlockInfo **free_block_lists [MS_BLOCK_TYPE_MAX];
 
-#ifdef SGEN_PARALLEL_MARK
-#ifdef HAVE_KW_THREAD
-static __thread MSBlockInfo ***workers_free_block_lists;
-#else
-static MonoNativeTlsKey workers_free_block_lists_key;
-#endif
-#endif
-
-static long long stat_major_blocks_alloced = 0;
-static long long stat_major_blocks_freed = 0;
-static long long stat_major_blocks_lazy_swept = 0;
-static long long stat_major_objects_evacuated = 0;
+static guint64 stat_major_blocks_alloced = 0;
+static guint64 stat_major_blocks_freed = 0;
+static guint64 stat_major_blocks_lazy_swept = 0;
+static guint64 stat_major_objects_evacuated = 0;
 
 #if SIZEOF_VOID_P != 8
-static long long stat_major_blocks_freed_ideal = 0;
-static long long stat_major_blocks_freed_less_ideal = 0;
-static long long stat_major_blocks_freed_individual = 0;
-static long long stat_major_blocks_alloced_less_ideal = 0;
+static guint64 stat_major_blocks_freed_ideal = 0;
+static guint64 stat_major_blocks_freed_less_ideal = 0;
+static guint64 stat_major_blocks_freed_individual = 0;
+static guint64 stat_major_blocks_alloced_less_ideal = 0;
 #endif
 
 #ifdef SGEN_COUNT_NUMBER_OF_MAJOR_OBJECTS_MARKED
-static long long num_major_objects_marked = 0;
+static guint64 num_major_objects_marked = 0;
 #define INC_NUM_MAJOR_OBJECTS_MARKED() (++num_major_objects_marked)
 #else
 #define INC_NUM_MAJOR_OBJECTS_MARKED()
 #endif
 
+#ifdef SGEN_HEAVY_BINARY_PROTOCOL
+static mono_mutex_t scanned_objects_list_lock;
+static SgenPointerQueue scanned_objects_list;
+
+static void
+add_scanned_object (void *ptr)
+{
+       if (!binary_protocol_is_enabled ())
+               return;
+
+       mono_mutex_lock (&scanned_objects_list_lock);
+       sgen_pointer_queue_add (&scanned_objects_list, ptr);
+       mono_mutex_unlock (&scanned_objects_list_lock);
+}
+#endif
+
 static void
 sweep_block (MSBlockInfo *block, gboolean during_major_collection);
 
@@ -264,55 +228,12 @@ ms_find_block_obj_size_index (size_t size)
 
 #define FREE_BLOCKS_FROM(lists,p,r)    (lists [((p) ? MS_BLOCK_FLAG_PINNED : 0) | ((r) ? MS_BLOCK_FLAG_REFS : 0)])
 #define FREE_BLOCKS(p,r)               (FREE_BLOCKS_FROM (free_block_lists, (p), (r)))
-#ifdef SGEN_PARALLEL_MARK
-#ifdef HAVE_KW_THREAD
-#define FREE_BLOCKS_LOCAL(p,r)         (FREE_BLOCKS_FROM (workers_free_block_lists, (p), (r)))
-#else
-#define FREE_BLOCKS_LOCAL(p,r)         (FREE_BLOCKS_FROM (((MSBlockInfo***)(mono_native_tls_get_value (workers_free_block_lists_key))), (p), (r)))
-#endif
-#else
-//#define FREE_BLOCKS_LOCAL(p,r)               (FREE_BLOCKS_FROM (free_block_lists, (p), (r)))
-#endif
 
 #define MS_BLOCK_OBJ_SIZE_INDEX(s)                             \
        (((s)+7)>>3 < MS_NUM_FAST_BLOCK_OBJ_SIZE_INDEXES ?      \
         fast_block_obj_size_indexes [((s)+7)>>3] :             \
         ms_find_block_obj_size_index ((s)))
 
-#ifdef FIXED_HEAP
-static void*
-major_alloc_heap (mword nursery_size, mword nursery_align, int the_nursery_bits)
-{
-       char *nursery_start;
-       mword major_heap_size = ms_heap_num_blocks * MS_BLOCK_SIZE;
-       mword alloc_size = nursery_size + major_heap_size;
-       mword i;
-
-       g_assert (ms_heap_num_blocks > 0);
-       g_assert (nursery_size % MS_BLOCK_SIZE == 0);
-       if (nursery_align)
-               g_assert (nursery_align % MS_BLOCK_SIZE == 0);
-
-       nursery_start = sgen_alloc_os_memory_aligned (alloc_size, nursery_align ? nursery_align : MS_BLOCK_SIZE, SGEN_ALLOC_HEAP | SGEN_ALLOC_ACTIVATE, "heap");
-       ms_heap_start = nursery_start + nursery_size;
-       ms_heap_end = ms_heap_start + major_heap_size;
-
-       block_infos = sgen_alloc_internal_dynamic (sizeof (MSBlockInfo) * ms_heap_num_blocks, INTERNAL_MEM_MS_BLOCK_INFO, TRUE);
-
-       for (i = 0; i < ms_heap_num_blocks; ++i) {
-               block_infos [i].block = ms_heap_start + i * MS_BLOCK_SIZE;
-               if (i < ms_heap_num_blocks - 1)
-                       block_infos [i].next_free = &block_infos [i + 1];
-               else
-                       block_infos [i].next_free = NULL;
-               block_infos [i].zeroed = TRUE;
-       }
-
-       empty_blocks = &block_infos [0];
-
-       return nursery_start;
-}
-#else
 static void*
 major_alloc_heap (mword nursery_size, mword nursery_align, int the_nursery_bits)
 {
@@ -324,44 +245,13 @@ major_alloc_heap (mword nursery_size, mword nursery_align, int the_nursery_bits)
 
        return start;
 }
-#endif
 
 static void
 update_heap_boundaries_for_block (MSBlockInfo *block)
 {
-       sgen_update_heap_boundaries ((mword)block->block, (mword)block->block + MS_BLOCK_SIZE);
-}
-
-#ifdef FIXED_HEAP
-static MSBlockInfo*
-ms_get_empty_block (void)
-{
-       MSBlockInfo *block;
-
-       g_assert (empty_blocks);
-
-       do {
-               block = empty_blocks;
-       } while (SGEN_CAS_PTR ((gpointer*)&empty_blocks, block->next_free, block) != block);
-
-       block->used = TRUE;
-
-       if (!block->zeroed)
-               memset (block->block, 0, MS_BLOCK_SIZE);
-
-       return block;
+       sgen_update_heap_boundaries ((mword)MS_BLOCK_FOR_BLOCK_INFO (block), (mword)MS_BLOCK_FOR_BLOCK_INFO (block) + MS_BLOCK_SIZE);
 }
 
-static void
-ms_free_block (MSBlockInfo *block)
-{
-       block->next_free = empty_blocks;
-       empty_blocks = block;
-       block->used = FALSE;
-       block->zeroed = FALSE;
-       sgen_memgov_release_space (MS_BLOCK_SIZE, SPACE_MAJOR);
-}
-#else
 static void*
 ms_get_empty_block (void)
 {
@@ -440,7 +330,6 @@ ms_free_block (void *block)
 
        SGEN_ATOMIC_ADD_P (num_empty_blocks, 1);
 }
-#endif
 
 //#define MARKSWEEP_CONSISTENCY_CHECK
 
@@ -459,30 +348,19 @@ check_block_free_list (MSBlockInfo *block, int size, gboolean pinned)
                if (block->swept)
                        g_assert (block->free_list);
 
-#ifdef FIXED_HEAP
-               /* the block must not be in the empty_blocks list */
-               for (b = empty_blocks; b; b = b->next_free)
-                       g_assert (b != block);
-#endif
-               /* the block must be in the all_blocks list */
-               for (b = all_blocks; b; b = b->next) {
-                       if (b == block)
-                               break;
-               }
-               g_assert (b == block);
+               /* the block must be in the allocated_blocks array */
+               g_assert (sgen_pointer_queue_find (&allocated_blocks, BLOCK_TAG (block)) != (size_t)-1);
        }
 }
 
 static void
 check_empty_blocks (void)
 {
-#ifndef FIXED_HEAP
        void *p;
        size_t i = 0;
        for (p = empty_blocks; p; p = *(void**)p)
                ++i;
        g_assert (i == num_empty_blocks);
-#endif
 }
 
 static void
@@ -497,10 +375,8 @@ consistency_check (void)
                int num_free = 0;
                void **free;
 
-#ifndef FIXED_HEAP
                /* check block header */
                g_assert (((MSBlockHeader*)block->block)->info == block);
-#endif
 
                /* count number of free slots */
                for (i = 0; i < count; ++i) {
@@ -540,12 +416,6 @@ ms_alloc_block (int size_index, gboolean pinned, gboolean has_references)
        int size = block_obj_sizes [size_index];
        int count = MS_BLOCK_FREE / size;
        MSBlockInfo *info;
-#ifdef SGEN_PARALLEL_MARK
-       MSBlockInfo *next;
-#endif
-#ifndef FIXED_HEAP
-       MSBlockHeader *header;
-#endif
        MSBlockInfo **free_blocks = FREE_BLOCKS (pinned, has_references);
        char *obj_start;
        int i;
@@ -553,11 +423,7 @@ ms_alloc_block (int size_index, gboolean pinned, gboolean has_references)
        if (!sgen_memgov_try_alloc_space (MS_BLOCK_SIZE, SPACE_MAJOR))
                return FALSE;
 
-#ifdef FIXED_HEAP
-       info = ms_get_empty_block ();
-#else
-       info = sgen_alloc_internal (INTERNAL_MEM_MS_BLOCK_INFO);
-#endif
+       info = (MSBlockInfo*)ms_get_empty_block ();
 
        SGEN_ASSERT (9, count >= 2, "block with %d objects, it must hold at least 2", count);
 
@@ -574,12 +440,6 @@ ms_alloc_block (int size_index, gboolean pinned, gboolean has_references)
         */
        info->is_to_space = (sgen_get_current_collection_generation () == GENERATION_OLD);
        info->swept = 1;
-#ifndef FIXED_HEAP
-       info->block = ms_get_empty_block ();
-
-       header = (MSBlockHeader*) info->block;
-       header->info = info;
-#endif
 #ifdef SGEN_HAVE_CONCURRENT_MARK
        info->cardtable_mod_union = NULL;
 #endif
@@ -587,7 +447,7 @@ ms_alloc_block (int size_index, gboolean pinned, gboolean has_references)
        update_heap_boundaries_for_block (info);
 
        /* build free list */
-       obj_start = info->block + MS_BLOCK_SKIP;
+       obj_start = MS_BLOCK_FOR_BLOCK_INFO (info) + MS_BLOCK_SKIP;
        info->free_list = (void**)obj_start;
        /* we're skipping the last one - it must be nulled */
        for (i = 0; i < count - 1; ++i) {
@@ -598,21 +458,10 @@ ms_alloc_block (int size_index, gboolean pinned, gboolean has_references)
        /* the last one */
        *(void**)obj_start = NULL;
 
-#ifdef SGEN_PARALLEL_MARK
-       do {
-               next = info->next_free = free_blocks [size_index];
-       } while (SGEN_CAS_PTR ((void**)&free_blocks [size_index], info, next) != next);
-
-       do {
-               next = info->next = all_blocks;
-       } while (SGEN_CAS_PTR ((void**)&all_blocks, info, next) != next);
-#else
        info->next_free = free_blocks [size_index];
        free_blocks [size_index] = info;
 
-       info->next = all_blocks;
-       all_blocks = info;
-#endif
+       sgen_pointer_queue_add (&allocated_blocks, BLOCK_TAG (info));
 
        ++num_major_sections;
        return TRUE;
@@ -624,7 +473,7 @@ obj_is_from_pinned_alloc (char *ptr)
        MSBlockInfo *block;
 
        FOREACH_BLOCK (block) {
-               if (ptr >= block->block && ptr <= block->block + MS_BLOCK_SIZE)
+               if (ptr >= MS_BLOCK_FOR_BLOCK_INFO (block) && ptr <= MS_BLOCK_FOR_BLOCK_INFO (block) + MS_BLOCK_SIZE)
                        return block->pinned;
        } END_FOREACH_BLOCK;
        return FALSE;
@@ -656,86 +505,6 @@ unlink_slot_from_free_list_uncontested (MSBlockInfo **free_blocks, int size_inde
        return obj;
 }
 
-#ifdef SGEN_PARALLEL_MARK
-static gboolean
-try_remove_block_from_free_list (MSBlockInfo *block, MSBlockInfo **free_blocks, int size_index)
-{
-       /*
-        * No more free slots in the block, so try to free the block.
-        * Don't try again if we don't succeed - another thread will
-        * already have done it.
-        */
-       MSBlockInfo *next_block = block->next_free;
-       if (SGEN_CAS_PTR ((void**)&free_blocks [size_index], next_block, block) == block) {
-               /*
-               void *old = SGEN_CAS_PTR ((void**)&block->next_free, NULL, next_block);
-               g_assert (old == next_block);
-               */
-               block->next_free = NULL;
-               return TRUE;
-       }
-       return FALSE;
-}
-
-static void*
-alloc_obj_par (MonoVTable *vtable, int size, gboolean pinned, gboolean has_references)
-{
-       int size_index = MS_BLOCK_OBJ_SIZE_INDEX (size);
-       MSBlockInfo **free_blocks_local = FREE_BLOCKS_LOCAL (pinned, has_references);
-       MSBlockInfo *block;
-       void *obj;
-
-#ifdef SGEN_HAVE_CONCURRENT_MARK
-       if (concurrent_mark)
-               g_assert_not_reached ();
-#endif
-
-       SGEN_ASSERT (9, current_collection_generation == GENERATION_OLD, "old gen parallel allocator called from a %d collection", current_collection_generation);
-
-       if (free_blocks_local [size_index]) {
-       get_slot:
-               obj = unlink_slot_from_free_list_uncontested (free_blocks_local, size_index);
-       } else {
-               MSBlockInfo **free_blocks = FREE_BLOCKS (pinned, has_references);
-
-       get_block:
-               block = free_blocks [size_index];
-               if (block) {
-                       if (!try_remove_block_from_free_list (block, free_blocks, size_index))
-                               goto get_block;
-
-                       g_assert (block->next_free == NULL);
-                       g_assert (block->free_list);
-                       block->next_free = free_blocks_local [size_index];
-                       free_blocks_local [size_index] = block;
-
-                       goto get_slot;
-               } else {
-                       gboolean success;
-
-                       LOCK_MS_BLOCK_LIST;
-                       success = ms_alloc_block (size_index, pinned, has_references);
-                       UNLOCK_MS_BLOCK_LIST;
-
-                       if (G_UNLIKELY (!success))
-                               return NULL;
-
-                       goto get_block;
-               }
-       }
-
-       *(MonoVTable**)obj = vtable;
-
-       return obj;
-}
-
-static void*
-major_par_alloc_object (MonoVTable *vtable, size_t size, gboolean has_references)
-{
-       return alloc_obj_par (vtable, size, FALSE, has_references);
-}
-#endif
-
 static void*
 alloc_obj (MonoVTable *vtable, size_t size, gboolean pinned, gboolean has_references)
 {
@@ -743,11 +512,6 @@ alloc_obj (MonoVTable *vtable, size_t size, gboolean pinned, gboolean has_refere
        MSBlockInfo **free_blocks = FREE_BLOCKS (pinned, has_references);
        void *obj;
 
-#ifdef SGEN_PARALLEL_MARK
-       SGEN_ASSERT (9, current_collection_generation == GENERATION_OLD, "old gen parallel allocator called from a %d collection", current_collection_generation);
-
-#endif
-
        if (!free_blocks [size_index]) {
                if (G_UNLIKELY (!ms_alloc_block (size_index, pinned, has_references)))
                        return NULL;
@@ -847,8 +611,6 @@ major_alloc_degraded (MonoVTable *vtable, size_t size)
        return obj;
 }
 
-#define MAJOR_OBJ_IS_IN_TO_SPACE(obj)  FALSE
-
 /*
  * obj is some object.  If it's not in the major heap (i.e. if it's in
  * the nursery or LOS), return FALSE.  Otherwise return whether it's
@@ -859,24 +621,16 @@ major_is_object_live (char *obj)
 {
        MSBlockInfo *block;
        int word, bit;
-#ifndef FIXED_HEAP
        mword objsize;
-#endif
 
        if (sgen_ptr_in_nursery (obj))
                return FALSE;
 
-#ifdef FIXED_HEAP
-       /* LOS */
-       if (!MS_PTR_IN_SMALL_MAJOR_HEAP (obj))
-               return FALSE;
-#else
        objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)obj));
 
        /* LOS */
        if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
                return FALSE;
-#endif
 
        /* now we know it's in a major block */
        block = MS_BLOCK_FOR_OBJ (obj);
@@ -891,7 +645,7 @@ major_ptr_is_in_non_pinned_space (char *ptr, char **start)
        MSBlockInfo *block;
 
        FOREACH_BLOCK (block) {
-               if (ptr >= block->block && ptr <= block->block + MS_BLOCK_SIZE) {
+               if (ptr >= MS_BLOCK_FOR_BLOCK_INFO (block) && ptr <= MS_BLOCK_FOR_BLOCK_INFO (block) + MS_BLOCK_SIZE) {
                        int count = MS_BLOCK_FREE / block->obj_size;
                        int i;
 
@@ -952,7 +706,7 @@ major_is_valid_object (char *object)
                int idx;
                char *obj;
 
-               if ((block->block > object) || ((block->block + MS_BLOCK_SIZE) <= object))
+               if ((MS_BLOCK_FOR_BLOCK_INFO (block) > object) || ((MS_BLOCK_FOR_BLOCK_INFO (block) + MS_BLOCK_SIZE) <= object))
                        continue;
 
                idx = MS_BLOCK_OBJ_INDEX (object, block);
@@ -979,11 +733,11 @@ major_describe_pointer (char *ptr)
                int w, b;
                gboolean marked;
 
-               if ((block->block > ptr) || ((block->block + MS_BLOCK_SIZE) <= ptr))
+               if ((MS_BLOCK_FOR_BLOCK_INFO (block) > ptr) || ((MS_BLOCK_FOR_BLOCK_INFO (block) + MS_BLOCK_SIZE) <= ptr))
                        continue;
 
                SGEN_LOG (0, "major-ptr (block %p sz %d pin %d ref %d)\n",
-                       block->block, block->obj_size, block->pinned, block->has_references);
+                       MS_BLOCK_FOR_BLOCK_INFO (block), block->obj_size, block->pinned, block->has_references);
 
                idx = MS_BLOCK_OBJ_INDEX (ptr, block);
                obj = (char*)MS_BLOCK_OBJ (block, idx);
@@ -1061,7 +815,7 @@ major_dump_heap (FILE *heap_dump_file)
                                        start = i;
                        } else {
                                if (start >= 0) {
-                                       sgen_dump_occupied (MS_BLOCK_OBJ (block, start), MS_BLOCK_OBJ (block, i), block->block);
+                                       sgen_dump_occupied (MS_BLOCK_OBJ (block, start), MS_BLOCK_OBJ (block, i), MS_BLOCK_FOR_BLOCK_INFO (block));
                                        start = -1;
                                }
                        }
@@ -1073,38 +827,25 @@ major_dump_heap (FILE *heap_dump_file)
 
 #define LOAD_VTABLE    SGEN_LOAD_VTABLE
 
-#define MS_MARK_OBJECT_AND_ENQUEUE_CHECKED(obj,block,queue) do {       \
+#define MS_MARK_OBJECT_AND_ENQUEUE_CHECKED(obj,desc,block,queue) do {  \
                int __word, __bit;                                      \
                MS_CALC_MARK_BIT (__word, __bit, (obj));                \
-               if (!MS_MARK_BIT ((block), __word, __bit) && MS_OBJ_ALLOCED ((obj), (block))) { \
+               if (!MS_MARK_BIT ((block), __word, __bit) && MS_OBJ_ALLOCED ((obj), (block))) { \
                        MS_SET_MARK_BIT ((block), __word, __bit);       \
-                       if ((block)->has_references)                    \
-                               GRAY_OBJECT_ENQUEUE ((queue), (obj));   \
+                       if (sgen_gc_descr_has_references (desc))                        \
+                               GRAY_OBJECT_ENQUEUE ((queue), (obj), (desc)); \
                        binary_protocol_mark ((obj), (gpointer)LOAD_VTABLE ((obj)), sgen_safe_object_get_size ((MonoObject*)(obj))); \
                        INC_NUM_MAJOR_OBJECTS_MARKED ();                \
                }                                                       \
        } while (0)
-#define MS_MARK_OBJECT_AND_ENQUEUE(obj,block,queue) do {               \
+#define MS_MARK_OBJECT_AND_ENQUEUE(obj,desc,block,queue) do {          \
                int __word, __bit;                                      \
                MS_CALC_MARK_BIT (__word, __bit, (obj));                \
-               SGEN_ASSERT (9, MS_OBJ_ALLOCED ((obj), (block)), "object %p not allocated", obj);       \
+               SGEN_ASSERT (9, MS_OBJ_ALLOCED ((obj), (block)), "object %p not allocated", obj); \
                if (!MS_MARK_BIT ((block), __word, __bit)) {            \
                        MS_SET_MARK_BIT ((block), __word, __bit);       \
-                       if ((block)->has_references)                    \
-                               GRAY_OBJECT_ENQUEUE ((queue), (obj));   \
-                       binary_protocol_mark ((obj), (gpointer)LOAD_VTABLE ((obj)), sgen_safe_object_get_size ((MonoObject*)(obj))); \
-                       INC_NUM_MAJOR_OBJECTS_MARKED ();                \
-               }                                                       \
-       } while (0)
-#define MS_PAR_MARK_OBJECT_AND_ENQUEUE(obj,block,queue) do {           \
-               int __word, __bit;                                      \
-               gboolean __was_marked;                                  \
-               SGEN_ASSERT (9, MS_OBJ_ALLOCED ((obj), (block)), "object %p not allocated", obj);       \
-               MS_CALC_MARK_BIT (__word, __bit, (obj));                \
-               MS_PAR_SET_MARK_BIT (__was_marked, (block), __word, __bit); \
-               if (!__was_marked) {                                    \
-                       if ((block)->has_references)                    \
-                               GRAY_OBJECT_ENQUEUE ((queue), (obj));   \
+                       if (sgen_gc_descr_has_references (desc))                        \
+                               GRAY_OBJECT_ENQUEUE ((queue), (obj), (desc)); \
                        binary_protocol_mark ((obj), (gpointer)LOAD_VTABLE ((obj)), sgen_safe_object_get_size ((MonoObject*)(obj))); \
                        INC_NUM_MAJOR_OBJECTS_MARKED ();                \
                }                                                       \
@@ -1122,189 +863,28 @@ pin_major_object (char *obj, SgenGrayQueue *queue)
 
        block = MS_BLOCK_FOR_OBJ (obj);
        block->has_pinned = TRUE;
-       MS_MARK_OBJECT_AND_ENQUEUE (obj, block, queue);
+       MS_MARK_OBJECT_AND_ENQUEUE (obj, sgen_obj_get_descriptor (obj), block, queue);
 }
 
 #include "sgen-major-copy-object.h"
 
-#ifdef SGEN_PARALLEL_MARK
-static void
-major_copy_or_mark_object (void **ptr, void *obj, SgenGrayQueue *queue)
-{
-       mword objsize;
-       MSBlockInfo *block;
-       MonoVTable *vt;
-
-       HEAVY_STAT (++stat_copy_object_called_major);
-
-       SGEN_ASSERT (9, obj, "null object from pointer %p", ptr);
-       SGEN_ASSERT (9, current_collection_generation == GENERATION_OLD, "old gen parallel allocator called from a %d collection", current_collection_generation);
-
-       if (sgen_ptr_in_nursery (obj)) {
-               int word, bit;
-               gboolean has_references;
-               void *destination;
-               mword vtable_word = *(mword*)obj;
-               vt = (MonoVTable*)(vtable_word & ~SGEN_VTABLE_BITS_MASK);
-
-               if (vtable_word & SGEN_FORWARDED_BIT) {
-                       *ptr = (void*)vt;
-                       return;
-               }
-
-               if (vtable_word & SGEN_PINNED_BIT)
-                       return;
-
-               /* An object in the nursery To Space has already been copied and grayed. Nothing to do. */
-               if (sgen_nursery_is_to_space (obj))
-                       return;
-
-               HEAVY_STAT (++stat_objects_copied_major);
-
-       do_copy_object:
-               objsize = SGEN_ALIGN_UP (sgen_par_object_get_size (vt, (MonoObject*)obj));
-               has_references = SGEN_VTABLE_HAS_REFERENCES (vt);
-
-               destination = sgen_minor_collector.par_alloc_for_promotion (vt, obj, objsize, has_references);
-               if (G_UNLIKELY (!destination)) {
-                       if (!sgen_ptr_in_nursery (obj)) {
-                               int size_index;
-                               block = MS_BLOCK_FOR_OBJ (obj);
-                               size_index = block->obj_size_index;
-                               evacuate_block_obj_sizes [size_index] = FALSE;
-                       }
-
-                       sgen_parallel_pin_or_update (ptr, obj, vt, queue);
-                       sgen_set_pinned_from_failed_allocation (objsize);
-                       return;
-               }
-
-               if (SGEN_CAS_PTR (obj, (void*)((mword)destination | SGEN_FORWARDED_BIT), vt) == vt) {
-                       gboolean was_marked;
-
-                       par_copy_object_no_checks (destination, vt, obj, objsize, has_references ? queue : NULL);
-                       obj = destination;
-                       *ptr = obj;
-
-                       /*
-                        * FIXME: If we make major_alloc_object() give
-                        * us the block info, too, we won't have to
-                        * re-fetch it here.
-                        *
-                        * FIXME (2): We should rework this to avoid all those nursery checks.
-                        */
-                       /*
-                        * For the split nursery allocator the object
-                        * might still be in the nursery despite
-                        * having being promoted, in which case we
-                        * can't mark it.
-                        */
-                       if (!sgen_ptr_in_nursery (obj)) {
-                               block = MS_BLOCK_FOR_OBJ (obj);
-                               MS_CALC_MARK_BIT (word, bit, obj);
-                               SGEN_ASSERT (9, !MS_MARK_BIT (block, word, bit), "object %p already marked", obj);
-                               MS_PAR_SET_MARK_BIT (was_marked, block, word, bit);
-                               binary_protocol_mark (obj, vt, sgen_safe_object_get_size ((MonoObject*)obj));
-                       }
-               } else {
-                       /*
-                        * FIXME: We have allocated destination, but
-                        * we cannot use it.  Give it back to the
-                        * allocator.
-                        */
-                       *(void**)destination = NULL;
-
-                       vtable_word = *(mword*)obj;
-                       g_assert (vtable_word & SGEN_FORWARDED_BIT);
-
-                       obj = (void*)(vtable_word & ~SGEN_VTABLE_BITS_MASK);
-
-                       *ptr = obj;
-
-                       HEAVY_STAT (++stat_slots_allocated_in_vain);
-               }
-       } else {
-#ifdef FIXED_HEAP
-               if (MS_PTR_IN_SMALL_MAJOR_HEAP (obj))
-#else
-               mword vtable_word = *(mword*)obj;
-               vt = (MonoVTable*)(vtable_word & ~SGEN_VTABLE_BITS_MASK);
-
-               /* see comment in the non-parallel version below */
-               if (vtable_word & SGEN_FORWARDED_BIT) {
-                       *ptr = (void*)vt;
-                       return;
-               }
-               objsize = SGEN_ALIGN_UP (sgen_par_object_get_size (vt, (MonoObject*)obj));
-
-               if (objsize <= SGEN_MAX_SMALL_OBJ_SIZE)
-#endif
-               {
-                       int size_index;
-
-                       block = MS_BLOCK_FOR_OBJ (obj);
-                       size_index = block->obj_size_index;
-
-                       if (!block->has_pinned && evacuate_block_obj_sizes [size_index]) {
-                               if (block->is_to_space)
-                                       return;
-
-#ifdef FIXED_HEAP
-                               {
-                                       mword vtable_word = *(mword*)obj;
-                                       vt = (MonoVTable*)(vtable_word & ~SGEN_VTABLE_BITS_MASK);
-
-                                       if (vtable_word & SGEN_FORWARDED_BIT) {
-                                               *ptr = (void*)vt;
-                                               return;
-                                       }
-                               }
-#endif
-
-                               HEAVY_STAT (++stat_major_objects_evacuated);
-                               goto do_copy_object;
-                       }
-
-                       MS_PAR_MARK_OBJECT_AND_ENQUEUE (obj, block, queue);
-               } else {
-                       LOSObject *bigobj = sgen_los_header_for_object (obj);
-                       mword size_word = bigobj->size;
-#ifdef FIXED_HEAP
-                       mword vtable_word = *(mword*)obj;
-                       vt = (MonoVTable*)(vtable_word & ~SGEN_VTABLE_BITS_MASK);
-#endif
-                       if (size_word & 1)
-                               return;
-                       binary_protocol_pin (obj, vt, sgen_safe_object_get_size ((MonoObject*)obj));
-                       if (SGEN_CAS_PTR ((void*)&bigobj->size, (void*)(size_word | 1), (void*)size_word) == (void*)size_word) {
-                               if (SGEN_VTABLE_HAS_REFERENCES (vt))
-                                       GRAY_OBJECT_ENQUEUE (queue, obj);
-                       } else {
-                               g_assert (sgen_los_object_is_pinned (obj));
-                       }
-               }
-       }
-}
-#else
 #ifdef SGEN_HAVE_CONCURRENT_MARK
 static void
-major_copy_or_mark_object_concurrent (void **ptr, void *obj, SgenGrayQueue *queue)
+major_copy_or_mark_object_with_evacuation_concurrent (void **ptr, void *obj, SgenGrayQueue *queue)
 {
+       SGEN_ASSERT (9, sgen_concurrent_collection_in_progress (), "Why are we scanning concurrently when there's no concurrent collection on?");
+       SGEN_ASSERT (9, !sgen_workers_are_working () || sgen_is_worker_thread (mono_native_thread_id_get ()), "We must not scan from two threads at the same time!");
+
        g_assert (!SGEN_OBJECT_IS_FORWARDED (obj));
 
        if (!sgen_ptr_in_nursery (obj)) {
-#ifdef FIXED_HEAP
-               if (MS_PTR_IN_SMALL_MAJOR_HEAP (obj))
-#else
                mword objsize;
 
                objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)obj));
 
-               if (objsize <= SGEN_MAX_SMALL_OBJ_SIZE)
-#endif
-               {
+               if (objsize <= SGEN_MAX_SMALL_OBJ_SIZE) {
                        MSBlockInfo *block = MS_BLOCK_FOR_OBJ (obj);
-                       MS_MARK_OBJECT_AND_ENQUEUE (obj, block, queue);
+                       MS_MARK_OBJECT_AND_ENQUEUE (obj, sgen_obj_get_descriptor (obj), block, queue);
                } else {
                        if (sgen_los_object_is_pinned (obj))
                                return;
@@ -1318,202 +898,115 @@ major_copy_or_mark_object_concurrent (void **ptr, void *obj, SgenGrayQueue *queu
 
                        sgen_los_pin_object (obj);
                        if (SGEN_OBJECT_HAS_REFERENCES (obj))
-                               GRAY_OBJECT_ENQUEUE (queue, obj);
+                               GRAY_OBJECT_ENQUEUE (queue, obj, sgen_obj_get_descriptor (obj));
                        INC_NUM_MAJOR_OBJECTS_MARKED ();
                }
        }
 }
 #endif
 
-static void
-major_copy_or_mark_object (void **ptr, void *obj, SgenGrayQueue *queue)
+static long long
+major_get_and_reset_num_major_objects_marked (void)
 {
-       MSBlockInfo *block;
-
-       HEAVY_STAT (++stat_copy_object_called_major);
-
-       SGEN_ASSERT (9, obj, "null object from pointer %p", ptr);
-       SGEN_ASSERT (9, current_collection_generation == GENERATION_OLD, "old gen parallel allocator called from a %d collection", current_collection_generation);
-
-       if (sgen_ptr_in_nursery (obj)) {
-               int word, bit;
-               char *forwarded, *old_obj;
-
-               if ((forwarded = SGEN_OBJECT_IS_FORWARDED (obj))) {
-                       *ptr = forwarded;
-                       return;
-               }
-               if (SGEN_OBJECT_IS_PINNED (obj))
-                       return;
-
-               /* An object in the nursery To Space has already been copied and grayed. Nothing to do. */
-               if (sgen_nursery_is_to_space (obj))
-                       return;
-
-               HEAVY_STAT (++stat_objects_copied_major);
-
-       do_copy_object:
-               old_obj = obj;
-               obj = copy_object_no_checks (obj, queue);
-               if (G_UNLIKELY (old_obj == obj)) {
-                       /*If we fail to evacuate an object we just stop doing it for a given block size as all other will surely fail too.*/
-                       if (!sgen_ptr_in_nursery (obj)) {
-                               int size_index;
-                               block = MS_BLOCK_FOR_OBJ (obj);
-                               size_index = block->obj_size_index;
-                               evacuate_block_obj_sizes [size_index] = FALSE;
-                               MS_MARK_OBJECT_AND_ENQUEUE (obj, block, queue);
-                       }
-                       return;
-               }
-               *ptr = obj;
-
-               /*
-                * FIXME: See comment for copy_object_no_checks().  If
-                * we have that, we can let the allocation function
-                * give us the block info, too, and we won't have to
-                * re-fetch it.
-                *
-                * FIXME (2): We should rework this to avoid all those nursery checks.
-                */
-               /*
-                * For the split nursery allocator the object might
-                * still be in the nursery despite having being
-                * promoted, in which case we can't mark it.
-                */
-               if (!sgen_ptr_in_nursery (obj)) {
-                       block = MS_BLOCK_FOR_OBJ (obj);
-                       MS_CALC_MARK_BIT (word, bit, obj);
-                       SGEN_ASSERT (9, !MS_MARK_BIT (block, word, bit), "object %p already marked", obj);
-                       MS_SET_MARK_BIT (block, word, bit);
-                       binary_protocol_mark (obj, (gpointer)LOAD_VTABLE (obj), sgen_safe_object_get_size ((MonoObject*)obj));
-               }
-       } else {
-               char *forwarded;
-#ifdef FIXED_HEAP
-               if (MS_PTR_IN_SMALL_MAJOR_HEAP (obj))
+#ifdef SGEN_COUNT_NUMBER_OF_MAJOR_OBJECTS_MARKED
+       long long num = num_major_objects_marked;
+       num_major_objects_marked = 0;
+       return num;
 #else
-               mword objsize;
-
-               /*
-                * If we have don't have a fixed heap we cannot know
-                * whether an object is in the LOS or in the small
-                * object major heap without checking its size.  To do
-                * that, however, we need to know that we actually
-                * have a valid object, not a forwarding pointer, so
-                * we have to do this check first.
-                */
-               if ((forwarded = SGEN_OBJECT_IS_FORWARDED (obj))) {
-                       *ptr = forwarded;
-                       return;
-               }
-
-               objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)obj));
-
-               if (objsize <= SGEN_MAX_SMALL_OBJ_SIZE)
-#endif
-               {
-                       int size_index;
-                       gboolean evacuate;
-
-                       block = MS_BLOCK_FOR_OBJ (obj);
-                       size_index = block->obj_size_index;
-                       evacuate = evacuate_block_obj_sizes [size_index];
-
-#ifdef FIXED_HEAP
-                       /*
-                        * We could also check for !block->has_pinned
-                        * here, but it would only make an uncommon case
-                        * faster, namely objects that are in blocks
-                        * whose slot sizes are evacuated but which have
-                        * pinned objects.
-                        */
-                       if (evacuate && (forwarded = SGEN_OBJECT_IS_FORWARDED (obj))) {
-                               *ptr = forwarded;
-                               return;
-                       }
+       return 0;
 #endif
+}
 
-                       if (evacuate && !block->has_pinned) {
-                               g_assert (!SGEN_OBJECT_IS_PINNED (obj));
-                               if (block->is_to_space)
-                                       return;
-                               HEAVY_STAT (++stat_major_objects_evacuated);
-                               goto do_copy_object;
-                       } else {
-                               MS_MARK_OBJECT_AND_ENQUEUE (obj, block, queue);
-                       }
-               } else {
-                       if (sgen_los_object_is_pinned (obj))
-                               return;
-                       binary_protocol_pin (obj, (gpointer)SGEN_LOAD_VTABLE (obj), sgen_safe_object_get_size ((MonoObject*)obj));
-
-#ifdef ENABLE_DTRACE
-                       if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
-                               MonoVTable *vt = (MonoVTable*)SGEN_LOAD_VTABLE (obj);
-                               MONO_GC_OBJ_PINNED ((mword)obj, sgen_safe_object_get_size (obj), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
-                       }
-#endif
+#ifdef HEAVY_STATISTICS
+static guint64 stat_optimized_copy;
+static guint64 stat_optimized_copy_nursery;
+static guint64 stat_optimized_copy_nursery_forwarded;
+static guint64 stat_optimized_copy_nursery_pinned;
+static guint64 stat_optimized_copy_major;
+static guint64 stat_optimized_copy_major_small_fast;
+static guint64 stat_optimized_copy_major_small_slow;
+static guint64 stat_optimized_copy_major_large;
+static guint64 stat_optimized_copy_major_forwarded;
+static guint64 stat_optimized_copy_major_small_evacuate;
+static guint64 stat_optimized_major_scan;
+static guint64 stat_optimized_major_scan_no_refs;
+
+static guint64 stat_drain_prefetch_fills;
+static guint64 stat_drain_prefetch_fill_failures;
+static guint64 stat_drain_loops;
+#endif
+
+static void major_scan_object_with_evacuation (char *start, mword desc, SgenGrayQueue *queue);
+
+#define COPY_OR_MARK_FUNCTION_NAME     major_copy_or_mark_object_no_evacuation
+#define SCAN_OBJECT_FUNCTION_NAME      major_scan_object_no_evacuation
+#define DRAIN_GRAY_STACK_FUNCTION_NAME drain_gray_stack_no_evacuation
+#include "sgen-marksweep-drain-gray-stack.h"
+
+#define COPY_OR_MARK_WITH_EVACUATION
+#define COPY_OR_MARK_FUNCTION_NAME     major_copy_or_mark_object_with_evacuation
+#define SCAN_OBJECT_FUNCTION_NAME      major_scan_object_with_evacuation
+#define DRAIN_GRAY_STACK_FUNCTION_NAME drain_gray_stack_with_evacuation
+#include "sgen-marksweep-drain-gray-stack.h"
 
-                       sgen_los_pin_object (obj);
-                       if (SGEN_OBJECT_HAS_REFERENCES (obj))
-                               GRAY_OBJECT_ENQUEUE (queue, obj);
+static gboolean
+drain_gray_stack (ScanCopyContext ctx)
+{
+       gboolean evacuation = FALSE;
+       int i;
+       for (i = 0; i < num_block_obj_sizes; ++i) {
+               if (evacuate_block_obj_sizes [i]) {
+                       evacuation = TRUE;
+                       break;
                }
        }
+
+       if (evacuation)
+               return drain_gray_stack_with_evacuation (ctx);
+       else
+               return drain_gray_stack_no_evacuation (ctx);
 }
+
+#ifdef SGEN_HAVE_CONCURRENT_MARK
+#include "sgen-marksweep-scan-object-concurrent.h"
 #endif
 
 static void
 major_copy_or_mark_object_canonical (void **ptr, SgenGrayQueue *queue)
 {
-       major_copy_or_mark_object (ptr, *ptr, queue);
+       major_copy_or_mark_object_with_evacuation (ptr, *ptr, queue);
 }
 
 #ifdef SGEN_HAVE_CONCURRENT_MARK
 static void
 major_copy_or_mark_object_concurrent_canonical (void **ptr, SgenGrayQueue *queue)
 {
-       major_copy_or_mark_object_concurrent (ptr, *ptr, queue);
-}
-
-static long long
-major_get_and_reset_num_major_objects_marked (void)
-{
-#ifdef SGEN_COUNT_NUMBER_OF_MAJOR_OBJECTS_MARKED
-       long long num = num_major_objects_marked;
-       num_major_objects_marked = 0;
-       return num;
-#else
-       return 0;
-#endif
+       major_copy_or_mark_object_with_evacuation_concurrent (ptr, *ptr, queue);
 }
 #endif
 
-#include "sgen-major-scan-object.h"
-
-#ifdef SGEN_HAVE_CONCURRENT_MARK
-#define SCAN_FOR_CONCURRENT_MARK
-#include "sgen-major-scan-object.h"
-#undef SCAN_FOR_CONCURRENT_MARK
-#endif
-
 static void
 mark_pinned_objects_in_block (MSBlockInfo *block, SgenGrayQueue *queue)
 {
-       int i;
+       void **entry, **end;
        int last_index = -1;
 
-       if (!block->pin_queue_num_entries)
+       if (block->pin_queue_first_entry == block->pin_queue_last_entry)
                return;
 
        block->has_pinned = TRUE;
 
-       for (i = 0; i < block->pin_queue_num_entries; ++i) {
-               int index = MS_BLOCK_OBJ_INDEX (block->pin_queue_start [i], block);
-               SGEN_ASSERT (9, index >= 0 && index < MS_BLOCK_FREE / block->obj_size, "invalid object %p index %d max-index %d", block->pin_queue_start [i], index, MS_BLOCK_FREE / block->obj_size);
+       entry = sgen_pinning_get_entry (block->pin_queue_first_entry);
+       end = sgen_pinning_get_entry (block->pin_queue_last_entry);
+
+       for (; entry < end; ++entry) {
+               int index = MS_BLOCK_OBJ_INDEX (*entry, block);
+               char *obj;
+               SGEN_ASSERT (9, index >= 0 && index < MS_BLOCK_FREE / block->obj_size, "invalid object %p index %d max-index %d", *entry, index, MS_BLOCK_FREE / block->obj_size);
                if (index == last_index)
                        continue;
-               MS_MARK_OBJECT_AND_ENQUEUE_CHECKED (MS_BLOCK_OBJ (block, index), block, queue);
+               obj = MS_BLOCK_OBJ (block, index);
+               MS_MARK_OBJECT_AND_ENQUEUE_CHECKED (obj, sgen_obj_get_descriptor (obj), block, queue);
                last_index = index;
        }
 }
@@ -1620,7 +1113,7 @@ static void
 ms_sweep (void)
 {
        int i;
-       MSBlockInfo **iter;
+       MSBlockInfo *block;
 
        /* statistics for evacuation */
        int *slots_available = alloca (sizeof (int) * num_block_obj_sizes);
@@ -1644,9 +1137,7 @@ ms_sweep (void)
        }
 
        /* traverse all blocks, free and zero unmarked objects */
-       iter = &all_blocks;
-       while (*iter) {
-               MSBlockInfo *block = *iter;
+       FOREACH_BLOCK (block) {
                int count;
                gboolean have_live = FALSE;
                gboolean has_pinned;
@@ -1691,8 +1182,6 @@ ms_sweep (void)
                                slots_available [obj_size_index] += count;
                        }
 
-                       iter = &block->next;
-
                        /*
                         * If there are free slots in the block, add
                         * the block to the corresponding free list.
@@ -1710,20 +1199,15 @@ ms_sweep (void)
                         * Blocks without live objects are removed from the
                         * block list and freed.
                         */
-                       *iter = block->next;
+                       DELETE_BLOCK_IN_FOREACH ();
 
                        binary_protocol_empty (MS_BLOCK_OBJ (block, 0), (char*)MS_BLOCK_OBJ (block, count) - (char*)MS_BLOCK_OBJ (block, 0));
-#ifdef FIXED_HEAP
                        ms_free_block (block);
-#else
-                       ms_free_block (block->block);
-
-                       sgen_free_internal (block, INTERNAL_MEM_MS_BLOCK_INFO);
-#endif
 
                        --num_major_sections;
                }
-       }
+       } END_FOREACH_BLOCK;
+       sgen_pointer_queue_remove_nulls (&allocated_blocks);
 
        for (i = 0; i < num_block_obj_sizes; ++i) {
                float usage = (float)slots_used [i] / (float)slots_available [i];
@@ -1869,29 +1353,34 @@ major_start_major_collection (void)
 
        // Sweep all unswept blocks
        if (lazy_sweep) {
-               MSBlockInfo **iter;
+               MSBlockInfo *block;
 
                MONO_GC_SWEEP_BEGIN (GENERATION_OLD, TRUE);
 
-               iter = &all_blocks;
-               while (*iter) {
-                       MSBlockInfo *block = *iter;
-
+               FOREACH_BLOCK (block) {
                        sweep_block (block, TRUE);
-
-                       iter = &block->next;
-               }
+               } END_FOREACH_BLOCK;
 
                MONO_GC_SWEEP_END (GENERATION_OLD, TRUE);
        }
 }
 
 static void
-major_finish_major_collection (void)
+major_finish_major_collection (ScannedObjectCounts *counts)
 {
+#ifdef SGEN_HEAVY_BINARY_PROTOCOL
+       if (binary_protocol_is_enabled ()) {
+               counts->num_scanned_objects = scanned_objects_list.next_slot;
+
+               sgen_pointer_queue_sort_uniq (&scanned_objects_list);
+               counts->num_unique_scanned_objects = scanned_objects_list.next_slot;
+
+               sgen_pointer_queue_clear (&scanned_objects_list);
+       }
+#endif
 }
 
-#if !defined(FIXED_HEAP) && SIZEOF_VOID_P != 8
+#if SIZEOF_VOID_P != 8
 static int
 compare_pointers (const void *va, const void *vb) {
        char *a = *(char**)va, *b = *(char**)vb;
@@ -1906,7 +1395,6 @@ compare_pointers (const void *va, const void *vb) {
 static void
 major_have_computer_minor_collection_allowance (void)
 {
-#ifndef FIXED_HEAP
        size_t section_reserve = sgen_get_minor_collection_allowance () / MS_BLOCK_SIZE;
 
        g_assert (have_swept);
@@ -2056,7 +1544,6 @@ major_have_computer_minor_collection_allowance (void)
                ++stat_major_blocks_freed_individual;
 #endif
        }
-#endif
 }
 
 static void
@@ -2065,8 +1552,8 @@ major_find_pin_queue_start_ends (SgenGrayQueue *queue)
        MSBlockInfo *block;
 
        FOREACH_BLOCK (block) {
-               block->pin_queue_start = sgen_find_optimized_pin_queue_area (block->block + MS_BLOCK_SKIP, block->block + MS_BLOCK_SIZE,
-                               &block->pin_queue_num_entries);
+               sgen_find_optimized_pin_queue_area (MS_BLOCK_FOR_BLOCK_INFO (block) + MS_BLOCK_SKIP, MS_BLOCK_FOR_BLOCK_INFO (block) + MS_BLOCK_SIZE,
+                               &block->pin_queue_first_entry, &block->pin_queue_last_entry);
        } END_FOREACH_BLOCK;
 }
 
@@ -2117,17 +1604,6 @@ get_num_major_sections (void)
 static gboolean
 major_handle_gc_param (const char *opt)
 {
-#ifdef FIXED_HEAP
-       if (g_str_has_prefix (opt, "major-heap-size=")) {
-               const char *arg = strchr (opt, '=') + 1;
-               size_t size;
-               if (!mono_gc_parse_environment_string_extract_number (arg, &size))
-                       return FALSE;
-               ms_heap_num_blocks = (size + MS_BLOCK_SIZE - 1) / MS_BLOCK_SIZE;
-               g_assert (ms_heap_num_blocks > 0);
-               return TRUE;
-       } else
-#endif
        if (g_str_has_prefix (opt, "evacuation-threshold=")) {
                const char *arg = strchr (opt, '=') + 1;
                int percentage = atoi (arg);
@@ -2153,9 +1629,6 @@ major_print_gc_param_usage (void)
 {
        fprintf (stderr,
                        ""
-#ifdef FIXED_HEAP
-                       "  major-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n"
-#endif
                        "  evacuation-threshold=P (where P is a percentage, an integer in 0-100)\n"
                        "  (no-)lazy-sweep\n"
                        );
@@ -2165,18 +1638,19 @@ static void
 major_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
 {
        MSBlockInfo *block;
+       gboolean has_references;
 
-       FOREACH_BLOCK (block) {
-               if (block->has_references)
-                       callback ((mword)block->block, MS_BLOCK_SIZE);
+       FOREACH_BLOCK_HAS_REFERENCES (block, has_references) {
+               if (has_references)
+                       callback ((mword)MS_BLOCK_FOR_BLOCK_INFO (block), MS_BLOCK_SIZE);
        } END_FOREACH_BLOCK;
 }
 
 #ifdef HEAVY_STATISTICS
-extern long long marked_cards;
-extern long long scanned_cards;
-extern long long scanned_objects;
-extern long long remarked_cards;
+extern guint64 marked_cards;
+extern guint64 scanned_cards;
+extern guint64 scanned_objects;
+extern guint64 remarked_cards;
 #endif
 
 #define CARD_WORDS_PER_BLOCK (CARDS_PER_BLOCK / SIZEOF_VOID_P)
@@ -2232,6 +1706,7 @@ static void
 major_scan_card_table (gboolean mod_union, SgenGrayQueue *queue)
 {
        MSBlockInfo *block;
+       gboolean has_references;
        ScanObjectFunc scan_func = sgen_get_current_object_ops ()->scan_object;
 
 #ifdef SGEN_HAVE_CONCURRENT_MARK
@@ -2241,15 +1716,15 @@ major_scan_card_table (gboolean mod_union, SgenGrayQueue *queue)
        g_assert (!mod_union);
 #endif
 
-       FOREACH_BLOCK (block) {
+       FOREACH_BLOCK_HAS_REFERENCES (block, has_references) {
                int block_obj_size;
                char *block_start;
 
-               if (!block->has_references)
+               if (!has_references)
                        continue;
 
                block_obj_size = block->obj_size;
-               block_start = block->block;
+               block_start = MS_BLOCK_FOR_BLOCK_INFO (block);
 
                if (block_obj_size >= CARD_SIZE_IN_BYTES) {
                        guint8 *cards;
@@ -2285,6 +1760,8 @@ major_scan_card_table (gboolean mod_union, SgenGrayQueue *queue)
                        end = block_start + MS_BLOCK_SIZE;
                        base = sgen_card_table_align_pointer (obj);
 
+                       cards += MS_BLOCK_SKIP >> CARD_BITS;
+
                        while (obj < end) {
                                size_t card_offset;
 
@@ -2339,6 +1816,8 @@ major_scan_card_table (gboolean mod_union, SgenGrayQueue *queue)
                        }
                        card_data_end = card_data + CARDS_PER_BLOCK;
 
+                       card_data += MS_BLOCK_SKIP >> CARD_BITS;
+
                        for (card_data = initial_skip_card (card_data); card_data < card_data_end; ++card_data) { //card_data = skip_card (card_data + 1, card_data_end)) {
                                size_t index;
                                size_t idx = card_data - card_base;
@@ -2377,7 +1856,7 @@ major_scan_card_table (gboolean mod_union, SgenGrayQueue *queue)
                                        }
 
                                        HEAVY_STAT (++scanned_objects);
-                                       scan_func (obj, queue);
+                                       scan_func (obj, sgen_obj_get_descriptor (obj), queue);
                                next_small:
                                        obj += block_obj_size;
                                }
@@ -2392,14 +1871,15 @@ static void
 major_count_cards (long long *num_total_cards, long long *num_marked_cards)
 {
        MSBlockInfo *block;
+       gboolean has_references;
        long long total_cards = 0;
        long long marked_cards = 0;
 
-       FOREACH_BLOCK (block) {
-               guint8 *cards = sgen_card_table_get_card_scan_address ((mword) block->block);
+       FOREACH_BLOCK_HAS_REFERENCES (block, has_references) {
+               guint8 *cards = sgen_card_table_get_card_scan_address ((mword) MS_BLOCK_FOR_BLOCK_INFO (block));
                int i;
 
-               if (!block->has_references)
+               if (!has_references)
                        continue;
 
                total_cards += CARDS_PER_BLOCK;
@@ -2423,7 +1903,7 @@ update_cardtable_mod_union (void)
                size_t num_cards;
 
                block->cardtable_mod_union = sgen_card_table_update_mod_union (block->cardtable_mod_union,
-                               block->block, MS_BLOCK_SIZE, &num_cards);
+                               MS_BLOCK_FOR_BLOCK_INFO (block), MS_BLOCK_SIZE, &num_cards);
 
                SGEN_ASSERT (0, num_cards == CARDS_PER_BLOCK, "Number of cards calculation is wrong");
        } END_FOREACH_BLOCK;
@@ -2433,7 +1913,7 @@ static guint8*
 major_get_cardtable_mod_union_for_object (char *obj)
 {
        MSBlockInfo *block = MS_BLOCK_FOR_OBJ (obj);
-       return &block->cardtable_mod_union [(obj - (char*)sgen_card_table_align_pointer (block->block)) >> CARD_BITS];
+       return &block->cardtable_mod_union [(obj - (char*)sgen_card_table_align_pointer (MS_BLOCK_FOR_BLOCK_INFO (block))) >> CARD_BITS];
 }
 #endif
 
@@ -2445,49 +1925,6 @@ alloc_free_block_lists (MSBlockInfo ***lists)
                lists [i] = sgen_alloc_internal_dynamic (sizeof (MSBlockInfo*) * num_block_obj_sizes, INTERNAL_MEM_MS_TABLES, TRUE);
 }
 
-#ifdef SGEN_PARALLEL_MARK
-static void*
-major_alloc_worker_data (void)
-{
-       /* FIXME: free this when the workers come down */
-       MSBlockInfo ***lists = malloc (sizeof (MSBlockInfo**) * MS_BLOCK_TYPE_MAX);
-       alloc_free_block_lists (lists);
-       return lists;
-}
-
-static void
-major_init_worker_thread (void *data)
-{
-       MSBlockInfo ***lists = data;
-       int i;
-
-       g_assert (lists && lists != free_block_lists);
-       for (i = 0; i < MS_BLOCK_TYPE_MAX; ++i) {
-               int j;
-               for (j = 0; j < num_block_obj_sizes; ++j)
-                       g_assert (!lists [i][j]);
-       }
-
-#ifdef HAVE_KW_THREAD
-       workers_free_block_lists = data;
-#else
-       mono_native_tls_set_value (workers_free_block_lists_key, data);
-#endif
-}
-
-static void
-major_reset_worker_data (void *data)
-{
-       MSBlockInfo ***lists = data;
-       int i;
-       for (i = 0; i < MS_BLOCK_TYPE_MAX; ++i) {
-               int j;
-               for (j = 0; j < num_block_obj_sizes; ++j)
-                       lists [i][j] = NULL;
-       }
-}
-#endif
-
 #undef pthread_create
 
 static void
@@ -2500,29 +1937,12 @@ post_param_init (SgenMajorCollector *collector)
 static void
 sgen_marksweep_init_internal (SgenMajorCollector *collector, gboolean is_concurrent)
 #else // SGEN_HAVE_CONCURRENT_MARK
-#ifdef SGEN_PARALLEL_MARK
-#ifdef FIXED_HEAP
-void
-sgen_marksweep_fixed_par_init (SgenMajorCollector *collector)
-#else // FIXED_HEAP
-void
-sgen_marksweep_par_init (SgenMajorCollector *collector)
-#endif // FIXED_HEAP
-#else // SGEN_PARALLEL_MARK
-#ifdef FIXED_HEAP
-void
-sgen_marksweep_fixed_init (SgenMajorCollector *collector)
-#else // FIXED_HEAP
 #error unknown configuration
-#endif // FIXED_HEAP
-#endif // SGEN_PARALLEL_MARK
 #endif // SGEN_HAVE_CONCURRENT_MARK
 {
        int i;
 
-#ifndef FIXED_HEAP
        sgen_register_fixed_internal_mem_type (INTERNAL_MEM_MS_BLOCK_INFO, sizeof (MSBlockInfo));
-#endif
 
        num_block_obj_sizes = ms_calculate_block_obj_sizes (MS_BLOCK_OBJ_SIZE_FACTOR, NULL);
        block_obj_sizes = sgen_alloc_internal_dynamic (sizeof (int) * num_block_obj_sizes, INTERNAL_MEM_MS_TABLES, TRUE);
@@ -2548,48 +1968,31 @@ sgen_marksweep_fixed_init (SgenMajorCollector *collector)
        for (i = 0; i < MS_NUM_FAST_BLOCK_OBJ_SIZE_INDEXES * 8; ++i)
                g_assert (MS_BLOCK_OBJ_SIZE_INDEX (i) == ms_find_block_obj_size_index (i));
 
-#ifdef SGEN_PARALLEL_MARK
-       LOCK_INIT (ms_block_list_mutex);
-#endif
-
-       mono_counters_register ("# major blocks allocated", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_major_blocks_alloced);
-       mono_counters_register ("# major blocks freed", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_major_blocks_freed);
-       mono_counters_register ("# major blocks lazy swept", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_major_blocks_lazy_swept);
-       mono_counters_register ("# major objects evacuated", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_major_objects_evacuated);
+       mono_counters_register ("# major blocks allocated", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_major_blocks_alloced);
+       mono_counters_register ("# major blocks freed", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_major_blocks_freed);
+       mono_counters_register ("# major blocks lazy swept", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_major_blocks_lazy_swept);
+       mono_counters_register ("# major objects evacuated", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_major_objects_evacuated);
 #if SIZEOF_VOID_P != 8
-       mono_counters_register ("# major blocks freed ideally", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_major_blocks_freed_ideal);
-       mono_counters_register ("# major blocks freed less ideally", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_major_blocks_freed_less_ideal);
-       mono_counters_register ("# major blocks freed individually", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_major_blocks_freed_individual);
-       mono_counters_register ("# major blocks allocated less ideally", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_major_blocks_alloced_less_ideal);
-#endif
-
-#ifdef SGEN_PARALLEL_MARK
-#ifndef HAVE_KW_THREAD
-       mono_native_tls_alloc (&workers_free_block_lists_key, NULL);
-#endif
+       mono_counters_register ("# major blocks freed ideally", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_major_blocks_freed_ideal);
+       mono_counters_register ("# major blocks freed less ideally", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_major_blocks_freed_less_ideal);
+       mono_counters_register ("# major blocks freed individually", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_major_blocks_freed_individual);
+       mono_counters_register ("# major blocks allocated less ideally", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_major_blocks_alloced_less_ideal);
 #endif
 
        collector->section_size = MAJOR_SECTION_SIZE;
-#ifdef SGEN_PARALLEL_MARK
-       collector->is_parallel = TRUE;
-       collector->alloc_worker_data = major_alloc_worker_data;
-       collector->init_worker_thread = major_init_worker_thread;
-       collector->reset_worker_data = major_reset_worker_data;
-#else
-       collector->is_parallel = FALSE;
-#endif
+
 #ifdef SGEN_HAVE_CONCURRENT_MARK
        concurrent_mark = is_concurrent;
        if (is_concurrent) {
                collector->is_concurrent = TRUE;
                collector->want_synchronous_collection = &want_evacuation;
-               collector->get_and_reset_num_major_objects_marked = major_get_and_reset_num_major_objects_marked;
        } else
 #endif
        {
                collector->is_concurrent = FALSE;
                collector->want_synchronous_collection = NULL;
        }
+       collector->get_and_reset_num_major_objects_marked = major_get_and_reset_num_major_objects_marked;
        collector->supports_cardtable = TRUE;
 
        collector->have_swept = &have_swept;
@@ -2600,9 +2003,6 @@ sgen_marksweep_fixed_init (SgenMajorCollector *collector)
        collector->alloc_degraded = major_alloc_degraded;
 
        collector->alloc_object = major_alloc_object;
-#ifdef SGEN_PARALLEL_MARK
-       collector->par_alloc_object = major_par_alloc_object;
-#endif
        collector->free_pinned_object = free_pinned_object;
        collector->iterate_objects = major_iterate_objects;
        collector->free_non_pinned_object = major_free_non_pinned_object;
@@ -2639,15 +2039,44 @@ sgen_marksweep_fixed_init (SgenMajorCollector *collector)
        collector->count_cards = major_count_cards;
 
        collector->major_ops.copy_or_mark_object = major_copy_or_mark_object_canonical;
-       collector->major_ops.scan_object = major_scan_object;
+       collector->major_ops.scan_object = major_scan_object_with_evacuation;
 #ifdef SGEN_HAVE_CONCURRENT_MARK
        if (is_concurrent) {
                collector->major_concurrent_ops.copy_or_mark_object = major_copy_or_mark_object_concurrent_canonical;
-               collector->major_concurrent_ops.scan_object = major_scan_object_concurrent;
+               collector->major_concurrent_ops.scan_object = major_scan_object_no_mark_concurrent;
                collector->major_concurrent_ops.scan_vtype = major_scan_vtype_concurrent;
        }
 #endif
 
+#if !defined (FIXED_HEAP) && !defined (SGEN_PARALLEL_MARK)
+       /* FIXME: this will not work with evacuation or the split nursery. */
+       if (!is_concurrent)
+               collector->drain_gray_stack = drain_gray_stack;
+
+#ifdef HEAVY_STATISTICS
+       mono_counters_register ("Optimized copy", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy);
+       mono_counters_register ("Optimized copy nursery", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy_nursery);
+       mono_counters_register ("Optimized copy nursery forwarded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy_nursery_forwarded);
+       mono_counters_register ("Optimized copy nursery pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy_nursery_pinned);
+       mono_counters_register ("Optimized copy major", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy_major);
+       mono_counters_register ("Optimized copy major small fast", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy_major_small_fast);
+       mono_counters_register ("Optimized copy major small slow", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy_major_small_slow);
+       mono_counters_register ("Optimized copy major large", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy_major_large);
+       mono_counters_register ("Optimized major scan", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_major_scan);
+       mono_counters_register ("Optimized major scan no refs", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_major_scan_no_refs);
+
+       mono_counters_register ("Gray stack drain loops", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_drain_loops);
+       mono_counters_register ("Gray stack prefetch fills", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_drain_prefetch_fills);
+       mono_counters_register ("Gray stack prefetch failures", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_drain_prefetch_fill_failures);
+#endif
+#endif
+
+#ifdef SGEN_HEAVY_BINARY_PROTOCOL
+       mono_mutex_init (&scanned_objects_list_lock);
+#endif
+
+       SGEN_ASSERT (0, SGEN_MAX_SMALL_OBJ_SIZE <= MS_BLOCK_FREE / 2, "MAX_SMALL_OBJ_SIZE must be at most MS_BLOCK_FREE / 2");
+
        /*cardtable requires major pages to be 8 cards aligned*/
        g_assert ((MS_BLOCK_SIZE % (8 * CARD_SIZE_IN_BYTES)) == 0);
 }