factor/vm/gc.cpp

303 lines
8.2 KiB
C++

#include "master.hpp"
namespace factor {
gc_event::gc_event(gc_op op_, factor_vm* parent)
: op(op_),
cards_scanned(0),
decks_scanned(0),
code_blocks_scanned(0),
start_time(nano_count()),
card_scan_time(0),
code_scan_time(0),
data_sweep_time(0),
code_sweep_time(0),
compaction_time(0) {
data_heap_before = parent->data_room();
code_heap_before = parent->code_room();
start_time = nano_count();
}
void gc_event::started_card_scan() { temp_time = nano_count(); }
void gc_event::ended_card_scan(cell cards_scanned_, cell decks_scanned_) {
cards_scanned += cards_scanned_;
decks_scanned += decks_scanned_;
card_scan_time = (cell)(nano_count() - temp_time);
}
void gc_event::started_code_scan() { temp_time = nano_count(); }
void gc_event::ended_code_scan(cell code_blocks_scanned_) {
code_blocks_scanned += code_blocks_scanned_;
code_scan_time = (cell)(nano_count() - temp_time);
}
void gc_event::started_data_sweep() { temp_time = nano_count(); }
void gc_event::ended_data_sweep() {
data_sweep_time = (cell)(nano_count() - temp_time);
}
void gc_event::started_code_sweep() { temp_time = nano_count(); }
void gc_event::ended_code_sweep() {
code_sweep_time = (cell)(nano_count() - temp_time);
}
void gc_event::started_compaction() { temp_time = nano_count(); }
void gc_event::ended_compaction() {
compaction_time = (cell)(nano_count() - temp_time);
}
void gc_event::ended_gc(factor_vm* parent) {
data_heap_after = parent->data_room();
code_heap_after = parent->code_room();
total_time = (cell)(nano_count() - start_time);
}
gc_state::gc_state(gc_op op_, factor_vm* parent) : op(op_) {
if (parent->gc_events) {
event = new gc_event(op, parent);
start_time = nano_count();
} else
event = NULL;
}
gc_state::~gc_state() {
if (event) {
delete event;
event = NULL;
}
}
void factor_vm::end_gc() {
if (gc_events) {
current_gc->event->ended_gc(this);
gc_events->push_back(*current_gc->event);
}
}
void factor_vm::start_gc_again() {
end_gc();
switch (current_gc->op) {
case collect_nursery_op:
/* Nursery collection can fail if aging does not have enough
free space to fit all live objects from nursery. */
current_gc->op = collect_aging_op;
break;
case collect_aging_op:
/* Aging collection can fail if the aging semispace cannot fit
all the live objects from the other aging semispace and the
nursery. */
current_gc->op = collect_to_tenured_op;
break;
default:
/* Nothing else should fail mid-collection due to insufficient
space in the target generation. */
critical_error("Bad GC op", current_gc->op);
break;
}
if (gc_events)
current_gc->event = new gc_event(current_gc->op, this);
}
void factor_vm::set_current_gc_op(gc_op op) {
current_gc->op = op;
if (gc_events)
current_gc->event->op = op;
}
void factor_vm::gc(gc_op op, cell requested_size, bool trace_contexts_p) {
FACTOR_ASSERT(!gc_off);
FACTOR_ASSERT(!current_gc);
/* Important invariant: tenured space must have enough contiguous free
space to fit the entire contents of the aging space and nursery. This is
because when doing a full collection, objects from younger generations
are promoted before any unreachable tenured objects are freed. */
FACTOR_ASSERT(!data->high_fragmentation_p());
current_gc = new gc_state(op, this);
atomic::store(&current_gc_p, true);
/* Keep trying to GC higher and higher generations until we don't run
out of space in the target generation. */
for (;;) {
try {
if (gc_events)
current_gc->event->op = current_gc->op;
switch (current_gc->op) {
case collect_nursery_op:
collect_nursery();
break;
case collect_aging_op:
/* We end up here if the above fails. */
collect_aging();
if (data->high_fragmentation_p()) {
/* Change GC op so that if we fail again, we crash. */
set_current_gc_op(collect_full_op);
collect_full(trace_contexts_p);
}
break;
case collect_to_tenured_op:
/* We end up here if the above fails. */
collect_to_tenured();
if (data->high_fragmentation_p()) {
/* Change GC op so that if we fail again, we crash. */
set_current_gc_op(collect_full_op);
collect_full(trace_contexts_p);
}
break;
case collect_full_op:
collect_full(trace_contexts_p);
break;
case collect_compact_op:
collect_compact(trace_contexts_p);
break;
case collect_growing_heap_op:
collect_growing_heap(requested_size, trace_contexts_p);
break;
default:
critical_error("Bad GC op", current_gc->op);
break;
}
break;
}
catch (const must_start_gc_again&) {
/* We come back here if the target generation is full. */
start_gc_again();
continue;
}
}
end_gc();
atomic::store(&current_gc_p, false);
delete current_gc;
current_gc = NULL;
/* Check the invariant again, just in case. */
FACTOR_ASSERT(!data->high_fragmentation_p());
}
/* primitive_minor_gc() is invoked by inline GC checks, and it needs to fill in
uninitialized stack locations before actually calling the GC. See the
comment in compiler.cfg.stacks.uninitialized for details. */
struct call_frame_scrubber {
factor_vm* parent;
context* ctx;
explicit call_frame_scrubber(factor_vm* parent_, context* ctx_)
: parent(parent_), ctx(ctx_) {}
void operator()(void* frame_top, cell frame_size, code_block* owner,
void* addr) {
cell return_address = owner->offset(addr);
gc_info* info = owner->block_gc_info();
FACTOR_ASSERT(return_address < owner->size());
cell index = info->return_address_index(return_address);
if (index != (cell) - 1)
ctx->scrub_stacks(info, index);
}
};
void factor_vm::scrub_context(context* ctx) {
call_frame_scrubber scrubber(this, ctx);
iterate_callstack(ctx, scrubber);
}
void factor_vm::scrub_contexts() {
std::set<context*>::const_iterator begin = active_contexts.begin();
std::set<context*>::const_iterator end = active_contexts.end();
while (begin != end) {
scrub_context(*begin);
begin++;
}
}
void factor_vm::primitive_minor_gc() {
scrub_contexts();
gc(collect_nursery_op, 0, /* requested size */
true /* trace contexts? */);
}
void factor_vm::primitive_full_gc() {
gc(collect_full_op, 0, /* requested size */
true /* trace contexts? */);
}
void factor_vm::primitive_compact_gc() {
gc(collect_compact_op, 0, /* requested size */
true /* trace contexts? */);
}
/*
* It is up to the caller to fill in the object's fields in a meaningful
* fashion!
*/
/* Allocates memory */
object* factor_vm::allot_large_object(cell type, cell size) {
/* If tenured space does not have enough room, collect and compact */
cell requested_size = size + data->high_water_mark();
if (!data->tenured->can_allot_p(requested_size)) {
primitive_compact_gc();
/* If it still won't fit, grow the heap */
if (!data->tenured->can_allot_p(requested_size)) {
gc(collect_growing_heap_op, size, /* requested size */
true /* trace contexts? */);
}
}
object* obj = data->tenured->allot(size);
/* Allows initialization code to store old->new pointers
without hitting the write barrier in the common case of
a nursery allocation */
write_barrier(obj, size);
obj->initialize(type);
return obj;
}
void factor_vm::primitive_enable_gc_events() {
gc_events = new std::vector<gc_event>();
}
/* Allocates memory */
void factor_vm::primitive_disable_gc_events() {
if (gc_events) {
growable_array result(this);
std::vector<gc_event>* gc_events = this->gc_events;
this->gc_events = NULL;
std::vector<gc_event>::const_iterator iter = gc_events->begin();
std::vector<gc_event>::const_iterator end = gc_events->end();
for (; iter != end; iter++) {
gc_event event = *iter;
byte_array* obj = byte_array_from_value(&event);
result.add(tag<byte_array>(obj));
}
result.trim();
ctx->push(result.elements.value());
delete this->gc_events;
} else
ctx->push(false_object);
}
}