/*
* To be used for interned strings and possibly MonoThread, reflection handles.
* We may want to explicitly free these objects.
*/
GCObject*
sgen_alloc_obj_pinned (GCVTable vtable, size_t size)
{
GCObject *p;
if (!SGEN_CAN_ALIGN_UP (size))
return NULL;
size = ALIGN_UP (size);
LOCK_GC;
if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
/* large objects are always pinned anyway */
p = (GCObject *)sgen_los_alloc_large_inner (vtable, size);
} else {
SGEN_ASSERT (9, sgen_client_vtable_is_inited (vtable), "class %s:%s is not initialized", sgen_client_vtable_get_namespace (vtable), sgen_client_vtable_get_name (vtable));
p = sgen_major_collector.alloc_small_pinned_obj (vtable, size, SGEN_VTABLE_HAS_REFERENCES (vtable));
}
if (G_LIKELY (p)) {
SGEN_LOG (6, "Allocated pinned object %p, vtable: %p (%s), size: %zd", p, vtable, sgen_client_vtable_get_name (vtable), size);
sgen_binary_protocol_alloc_pinned (p, vtable, size, sgen_client_get_provenance ());
}
UNLOCK_GC;
return p;
}
void
sgen_dump_pin_queue (void)
{
int i;
for (i = 0; i < last_num_pinned; ++i) {
GCObject *ptr = (GCObject *)pin_queue.data [i];
SGEN_LOG (3, "Bastard pinning obj %p (%s), size: %zd", ptr, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (ptr)), sgen_safe_object_get_size (ptr));
}
}
mword
sgen_build_nursery_fragments (GCMemSection *nursery_section, SgenGrayQueue *unpin_queue)
{
char *frag_start, *frag_end;
size_t frag_size;
SgenFragment *frags_ranges;
void **pin_start, **pin_entry, **pin_end;
#ifdef NALLOC_DEBUG
reset_alloc_records ();
#endif
/*The mutator fragments are done. We no longer need them. */
sgen_fragment_allocator_release (&mutator_allocator);
frag_start = sgen_nursery_start;
fragment_total = 0;
/* The current nursery might give us a fragment list to exclude [start, next[*/
frags_ranges = sgen_minor_collector.build_fragments_get_exclude_head ();
/* clear scan starts */
memset (nursery_section->scan_starts, 0, nursery_section->num_scan_start * sizeof (gpointer));
pin_start = pin_entry = sgen_pinning_get_entry (nursery_section->pin_queue_first_entry);
pin_end = sgen_pinning_get_entry (nursery_section->pin_queue_last_entry);
while (pin_entry < pin_end || frags_ranges) {
char *addr0, *addr1;
size_t size;
addr0 = addr1 = sgen_nursery_end;
if (pin_entry < pin_end)
addr0 = (char *)*pin_entry;
if (frags_ranges)
addr1 = frags_ranges->fragment_start;
if (addr0 < addr1) {
if (unpin_queue)
GRAY_OBJECT_ENQUEUE (unpin_queue, (GCObject*)addr0, sgen_obj_get_descriptor_safe ((GCObject*)addr0));
else
SGEN_UNPIN_OBJECT (addr0);
size = SGEN_ALIGN_UP (sgen_safe_object_get_size ((GCObject*)addr0));
CANARIFY_SIZE (size);
sgen_set_nursery_scan_start (addr0);
frag_end = addr0;
++pin_entry;
} else {
frag_end = addr1;
size = frags_ranges->fragment_next - addr1;
frags_ranges = frags_ranges->next_in_order;
}
frag_size = frag_end - frag_start;
if (size == 0)
continue;
g_assert (frag_size >= 0);
g_assert (size > 0);
if (frag_size && size)
add_nursery_frag (&mutator_allocator, frag_size, frag_start, frag_end);
frag_size = size;
#ifdef NALLOC_DEBUG
add_alloc_record (*pin_entry, frag_size, PINNING);
#endif
frag_start = frag_end + frag_size;
}
nursery_last_pinned_end = frag_start;
frag_end = sgen_nursery_end;
frag_size = frag_end - frag_start;
if (frag_size)
add_nursery_frag (&mutator_allocator, frag_size, frag_start, frag_end);
/* Now it's safe to release the fragments exclude list. */
sgen_minor_collector.build_fragments_release_exclude_head ();
/* First we reorder the fragment list to be in ascending address order. This makes H/W prefetchers happier. */
fragment_list_reverse (&mutator_allocator);
/*The collector might want to do something with the final nursery fragment list.*/
sgen_minor_collector.build_fragments_finish (&mutator_allocator);
if (!unmask (mutator_allocator.alloc_head)) {
SGEN_LOG (1, "Nursery fully pinned");
for (pin_entry = pin_start; pin_entry < pin_end; ++pin_entry) {
GCObject *p = (GCObject *)*pin_entry;
SGEN_LOG (3, "Bastard pinning obj %p (%s), size: %zd", p, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (p)), sgen_safe_object_get_size (p));
}
}
return fragment_total;
}
GCObject*
sgen_try_alloc_obj_nolock (GCVTable vtable, size_t size)
{
void **p;
char *new_next;
size_t real_size = size;
TLAB_ACCESS_INIT;
CANARIFY_SIZE(size);
size = ALIGN_UP (size);
SGEN_ASSERT (9, real_size >= SGEN_CLIENT_MINIMUM_OBJECT_SIZE, "Object too small");
SGEN_ASSERT (6, sgen_vtable_get_descriptor (vtable), "VTable without descriptor");
if (real_size > SGEN_MAX_SMALL_OBJ_SIZE)
return NULL;
if (G_UNLIKELY (size > sgen_tlab_size)) {
/* Allocate directly from the nursery */
p = (void **)sgen_nursery_alloc (size);
if (!p)
return NULL;
sgen_set_nursery_scan_start ((char*)p);
/*FIXME we should use weak memory ops here. Should help specially on x86. */
zero_tlab_if_necessary (p, size);
} else {
int available_in_tlab;
char *real_end;
/* tlab_next and tlab_temp_end are TLS vars so accessing them might be expensive */
p = (void**)TLAB_NEXT;
/* FIXME: handle overflow */
new_next = (char*)p + size;
real_end = TLAB_REAL_END;
available_in_tlab = (int)(real_end - (char*)p);//We'll never have tlabs > 2Gb
if (G_LIKELY (new_next < real_end)) {
TLAB_NEXT = new_next;
/* Second case, we overflowed temp end */
if (G_UNLIKELY (new_next >= TLAB_TEMP_END)) {
sgen_set_nursery_scan_start (new_next);
/* we just bump tlab_temp_end as well */
TLAB_TEMP_END = MIN (TLAB_REAL_END, TLAB_NEXT + SGEN_SCAN_START_SIZE);
SGEN_LOG (5, "Expanding local alloc: %p-%p", TLAB_NEXT, TLAB_TEMP_END);
}
} else if (available_in_tlab > SGEN_MAX_NURSERY_WASTE) {
/* Allocate directly from the nursery */
p = (void **)sgen_nursery_alloc (size);
if (!p)
return NULL;
zero_tlab_if_necessary (p, size);
} else {
size_t alloc_size = 0;
sgen_nursery_retire_region (p, available_in_tlab);
new_next = (char *)sgen_nursery_alloc_range (sgen_tlab_size, size, &alloc_size);
p = (void**)new_next;
if (!p)
return NULL;
TLAB_START = (char*)new_next;
TLAB_NEXT = new_next + size;
TLAB_REAL_END = new_next + alloc_size;
TLAB_TEMP_END = new_next + MIN (SGEN_SCAN_START_SIZE, alloc_size);
sgen_set_nursery_scan_start ((char*)p);
zero_tlab_if_necessary (new_next, alloc_size);
}
}
HEAVY_STAT (++stat_objects_alloced);
HEAVY_STAT (stat_bytes_alloced += size);
CANARIFY_ALLOC(p,real_size);
SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, sgen_client_vtable_get_name (vtable), size);
sgen_binary_protocol_alloc (p, vtable, size, sgen_client_get_provenance ());
g_assert (*p == NULL); /* FIXME disable this in non debug builds */
mono_atomic_store_seq (p, vtable);
return (GCObject*)p;
}
/*
* Provide a variant that takes just the vtable for small fixed-size objects.
* The aligned size is already computed and stored in vt->gc_descr.
* Note: every SGEN_SCAN_START_SIZE or so we are given the chance to do some special
* processing. We can keep track of where objects start, for example,
* so when we scan the thread stacks for pinned objects, we can start
* a search for the pinned object in SGEN_SCAN_START_SIZE chunks.
*/
GCObject*
sgen_alloc_obj_nolock (GCVTable vtable, size_t size)
{
/* FIXME: handle OOM */
void **p;
char *new_next;
size_t real_size = size;
TLAB_ACCESS_INIT;
CANARIFY_SIZE(size);
HEAVY_STAT (++stat_objects_alloced);
if (real_size <= SGEN_MAX_SMALL_OBJ_SIZE)
HEAVY_STAT (stat_bytes_alloced += size);
else
HEAVY_STAT (stat_bytes_alloced_los += size);
size = ALIGN_UP (size);
SGEN_ASSERT (6, sgen_vtable_get_descriptor (vtable), "VTable without descriptor");
if (G_UNLIKELY (sgen_has_per_allocation_action)) {
static int alloc_count;
int current_alloc = mono_atomic_inc_i32 (&alloc_count);
if (sgen_collect_before_allocs) {
if (((current_alloc % sgen_collect_before_allocs) == 0) && sgen_nursery_section) {
sgen_perform_collection (0, GENERATION_NURSERY, "collect-before-alloc-triggered", TRUE, TRUE);
if (!sgen_degraded_mode && sgen_can_alloc_size (size) && real_size <= SGEN_MAX_SMALL_OBJ_SIZE) {
// FIXME:
g_assert_not_reached ();
}
}
} else if (sgen_verify_before_allocs) {
if ((current_alloc % sgen_verify_before_allocs) == 0)
sgen_check_whole_heap_stw ();
}
}
/*
* We must already have the lock here instead of after the
* fast path because we might be interrupted in the fast path
* (after confirming that new_next < TLAB_TEMP_END) by the GC,
* and we'll end up allocating an object in a fragment which
* no longer belongs to us.
*
* The managed allocator does not do this, but it's treated
* specially by the world-stopping code.
*/
if (real_size > SGEN_MAX_SMALL_OBJ_SIZE) {
p = (void **)sgen_los_alloc_large_inner (vtable, ALIGN_UP (real_size));
} else {
/* tlab_next and tlab_temp_end are TLS vars so accessing them might be expensive */
p = (void**)TLAB_NEXT;
/* FIXME: handle overflow */
new_next = (char*)p + size;
TLAB_NEXT = new_next;
if (G_LIKELY (new_next < TLAB_TEMP_END)) {
/* Fast path */
CANARIFY_ALLOC(p,real_size);
SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, sgen_client_vtable_get_name (vtable), size);
sgen_binary_protocol_alloc (p , vtable, size, sgen_client_get_provenance ());
g_assert (*p == NULL);
mono_atomic_store_seq (p, vtable);
return (GCObject*)p;
}
/* Slow path */
/* there are two cases: the object is too big or we run out of space in the TLAB */
/* we also reach here when the thread does its first allocation after a minor
* collection, since the tlab_ variables are initialized to NULL.
* there can be another case (from ORP), if we cooperate with the runtime a bit:
* objects that need finalizers can have the high bit set in their size
* so the above check fails and we can readily add the object to the queue.
* This avoids taking again the GC lock when registering, but this is moot when
* doing thread-local allocation, so it may not be a good idea.
*/
if (TLAB_NEXT >= TLAB_REAL_END) {
int available_in_tlab;
/*
* Run out of space in the TLAB. When this happens, some amount of space
* remains in the TLAB, but not enough to satisfy the current allocation
* request. Currently, we retire the TLAB in all cases, later we could
* keep it if the remaining space is above a treshold, and satisfy the
* allocation directly from the nursery.
*/
TLAB_NEXT -= size;
/* when running in degraded mode, we continue allocing that way
* for a while, to decrease the number of useless nursery collections.
*/
if (sgen_degraded_mode && sgen_degraded_mode < sgen_nursery_size)
return alloc_degraded (vtable, size, FALSE);
available_in_tlab = (int)(TLAB_REAL_END - TLAB_NEXT);//We'll never have tlabs > 2Gb
if (size > sgen_tlab_size || available_in_tlab > SGEN_MAX_NURSERY_WASTE) {
/* Allocate directly from the nursery */
p = (void **)sgen_nursery_alloc (size);
if (!p) {
/*
* We couldn't allocate from the nursery, so we try
* collecting. Even after the collection, we might
* still not have enough memory to allocate the
* object. The reason will most likely be that we've
* run out of memory, but there is the theoretical
* possibility that other threads might have consumed
* the freed up memory ahead of us.
*
* What we do in this case is allocate degraded, i.e.,
* from the major heap.
*
* Ideally we'd like to detect the case of other
* threads allocating ahead of us and loop (if we
* always loop we will loop endlessly in the case of
* OOM).
*/
sgen_ensure_free_space (real_size, GENERATION_NURSERY);
if (!sgen_degraded_mode)
p = (void **)sgen_nursery_alloc (size);
}
if (!p)
return alloc_degraded (vtable, size, TRUE);
zero_tlab_if_necessary (p, size);
} else {
size_t alloc_size = 0;
if (TLAB_START)
SGEN_LOG (3, "Retire TLAB: %p-%p [%ld]", TLAB_START, TLAB_REAL_END, (long)(TLAB_REAL_END - TLAB_NEXT - size));
sgen_nursery_retire_region (p, available_in_tlab);
p = (void **)sgen_nursery_alloc_range (sgen_tlab_size, size, &alloc_size);
if (!p) {
/* See comment above in similar case. */
sgen_ensure_free_space (sgen_tlab_size, GENERATION_NURSERY);
if (!sgen_degraded_mode)
p = (void **)sgen_nursery_alloc_range (sgen_tlab_size, size, &alloc_size);
}
if (!p)
return alloc_degraded (vtable, size, TRUE);
/* Allocate a new TLAB from the current nursery fragment */
TLAB_START = (char*)p;
TLAB_NEXT = TLAB_START;
TLAB_REAL_END = TLAB_START + alloc_size;
TLAB_TEMP_END = TLAB_START + MIN (SGEN_SCAN_START_SIZE, alloc_size);
zero_tlab_if_necessary (TLAB_START, alloc_size);
/* Allocate from the TLAB */
p = (void **)TLAB_NEXT;
TLAB_NEXT += size;
sgen_set_nursery_scan_start ((char*)p);
}
} else {
/* Reached tlab_temp_end */
/* record the scan start so we can find pinned objects more easily */
sgen_set_nursery_scan_start ((char*)p);
/* we just bump tlab_temp_end as well */
TLAB_TEMP_END = MIN (TLAB_REAL_END, TLAB_NEXT + SGEN_SCAN_START_SIZE);
SGEN_LOG (5, "Expanding local alloc: %p-%p", TLAB_NEXT, TLAB_TEMP_END);
}
CANARIFY_ALLOC(p,real_size);
}
if (G_LIKELY (p)) {
SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, sgen_client_vtable_get_name (vtable), size);
sgen_binary_protocol_alloc (p, vtable, size, sgen_client_get_provenance ());
mono_atomic_store_seq (p, vtable);
}
return (GCObject*)p;
}
/* LOCKING: requires that the GC lock is held */
void
sgen_collect_bridge_objects (int generation, ScanCopyContext ctx)
{
CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
GrayQueue *queue = ctx.queue;
SgenHashTable *hash_table = get_finalize_entry_hash_table (generation);
GCObject *object;
gpointer dummy G_GNUC_UNUSED;
GCObject *copy;
SgenPointerQueue moved_fin_objects;
sgen_pointer_queue_init (&moved_fin_objects, INTERNAL_MEM_TEMPORARY);
if (no_finalize)
return;
SGEN_HASH_TABLE_FOREACH (hash_table, GCObject *, object, gpointer, dummy) {
int tag = tagged_object_get_tag (object);
object = tagged_object_get_object (object);
/* Bridge code told us to ignore this one */
if (tag == BRIDGE_OBJECT_MARKED)
continue;
/* Object is a bridge object and major heap says it's dead */
if (major_collector.is_object_live (object))
continue;
/* Nursery says the object is dead. */
if (!sgen_gc_is_object_ready_for_finalization (object))
continue;
if (!sgen_client_bridge_is_bridge_object (object))
continue;
copy = object;
copy_func (©, queue);
sgen_client_bridge_register_finalized_object (copy);
if (hash_table == &minor_finalizable_hash && !ptr_in_nursery (copy)) {
/* remove from the list */
SGEN_HASH_TABLE_FOREACH_REMOVE (TRUE);
/* insert it into the major hash */
sgen_hash_table_replace (&major_finalizable_hash, tagged_object_apply (copy, tag), NULL, NULL);
SGEN_LOG (5, "Promoting finalization of object %p (%s) (was at %p) to major table", copy, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (copy)), object);
continue;
} else if (copy != object) {
/* update pointer */
SGEN_HASH_TABLE_FOREACH_REMOVE (TRUE);
/* register for reinsertion */
sgen_pointer_queue_add (&moved_fin_objects, tagged_object_apply (copy, tag));
SGEN_LOG (5, "Updating object for finalization: %p (%s) (was at %p)", copy, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (copy)), object);
continue;
}
} SGEN_HASH_TABLE_FOREACH_END;
