vm/gc.cpp

   1 #include "master.hpp"
   2
   3 namespace factor
   4 {
   5
   6 gc_event::gc_event(gc_op op_, factor_vm *parent) :
   7         op(op_),
   8         cards_scanned(0),
   9         decks_scanned(0),
  10         code_blocks_scanned(0),
  11         start_time(nano_count()),
  12         card_scan_time(0),
  13         code_scan_time(0),
  14         data_sweep_time(0),
  15         code_sweep_time(0),
  16         compaction_time(0)
  17 {
  18         data_heap_before = parent->data_room();
  19         code_heap_before = parent->code_room();
  20         start_time = nano_count();
  21 }
  22
  23 void gc_event::started_card_scan()
  24 {
  25         temp_time = nano_count();
  26 }
  27
  28 void gc_event::ended_card_scan(cell cards_scanned_, cell decks_scanned_)
  29 {
  30         cards_scanned += cards_scanned_;
  31         decks_scanned += decks_scanned_;
  32         card_scan_time = (cell)(nano_count() - temp_time);
  33 }
  34
  35 void gc_event::started_code_scan()
  36 {
  37         temp_time = nano_count();
  38 }
  39
  40 void gc_event::ended_code_scan(cell code_blocks_scanned_)
  41 {
  42         code_blocks_scanned += code_blocks_scanned_;
  43         code_scan_time = (cell)(nano_count() - temp_time);
  44 }
  45
  46 void gc_event::started_data_sweep()
  47 {
  48         temp_time = nano_count();
  49 }
  50
  51 void gc_event::ended_data_sweep()
  52 {
  53         data_sweep_time = (cell)(nano_count() - temp_time);
  54 }
  55
  56 void gc_event::started_code_sweep()
  57 {
  58         temp_time = nano_count();
  59 }
  60
  61 void gc_event::ended_code_sweep()
  62 {
  63         code_sweep_time = (cell)(nano_count() - temp_time);
  64 }
  65
  66 void gc_event::started_compaction()
  67 {
  68         temp_time = nano_count();
  69 }
  70
  71 void gc_event::ended_compaction()
  72 {
  73         compaction_time = (cell)(nano_count() - temp_time);
  74 }
  75
  76 void gc_event::ended_gc(factor_vm *parent)
  77 {
  78         data_heap_after = parent->data_room();
  79         code_heap_after = parent->code_room();
  80         total_time = (cell)(nano_count() - start_time);
  81 }
  82
  83 gc_state::gc_state(gc_op op_, factor_vm *parent) : op(op_)
  84 {
  85         if(parent->gc_events)
  86         {
  87                 event = new gc_event(op,parent);
  88                 start_time = nano_count();
  89         }
  90         else
  91                 event = NULL;
  92 }
  93
  94 gc_state::~gc_state()
  95 {
  96         if(event)
  97         {
  98                 delete event;
  99                 event = NULL;
 100         }
 101 }
 102
 103 void factor_vm::end_gc()
 104 {
 105         if(gc_events)
 106         {
 107                 current_gc->event->ended_gc(this);
 108                 gc_events->push_back(*current_gc->event);
 109         }
 110 }
 111
 112 void factor_vm::start_gc_again()
 113 {
 114         end_gc();
 115
 116         switch(current_gc->op)
 117         {
 118         case collect_nursery_op:
 119                 current_gc->op = collect_aging_op;
 120                 break;
 121         case collect_aging_op:
 122                 current_gc->op = collect_to_tenured_op;
 123                 break;
 124         case collect_to_tenured_op:
 125                 current_gc->op = collect_full_op;
 126                 break;
 127         case collect_full_op:
 128         case collect_compact_op:
 129                 current_gc->op = collect_growing_heap_op;
 130                 break;
 131         default:
 132                 critical_error("Bad GC op",current_gc->op);
 133                 break;
 134         }
 135
 136         if(gc_events)
 137                 current_gc->event = new gc_event(current_gc->op,this);
 138 }
 139
 140 void factor_vm::set_current_gc_op(gc_op op)
 141 {
 142         current_gc->op = op;
 143         if(gc_events) current_gc->event->op = op;
 144 }
 145
 146 void factor_vm::gc(gc_op op, cell requested_bytes, bool trace_contexts_p)
 147 {
 148         /* Save and reset FPU state before, restore it after, so that
 149         nano_count() doesn't bomb on Windows if inexact traps are enabled
 150         (fun huh?) */
 151         cell fpu_state = get_fpu_state();
 152
 153         assert(!gc_off);
 154         assert(!current_gc);
 155
 156         current_gc = new gc_state(op,this);
 157
 158         /* Keep trying to GC higher and higher generations until we don't run out
 159         of space */
 160         for(;;)
 161         {
 162                 try
 163                 {
 164                         if(gc_events) current_gc->event->op = current_gc->op;
 165
 166                         switch(current_gc->op)
 167                         {
 168                         case collect_nursery_op:
 169                                 collect_nursery();
 170                                 break;
 171                         case collect_aging_op:
 172                                 collect_aging();
 173                                 if(data->high_fragmentation_p())
 174                                 {
 175                                         set_current_gc_op(collect_full_op);
 176                                         collect_full(trace_contexts_p);
 177                                 }
 178                                 break;
 179                         case collect_to_tenured_op:
 180                                 collect_to_tenured();
 181                                 if(data->high_fragmentation_p())
 182                                 {
 183                                         set_current_gc_op(collect_full_op);
 184                                         collect_full(trace_contexts_p);
 185                                 }
 186                                 break;
 187                         case collect_full_op:
 188                                 collect_full(trace_contexts_p);
 189                                 break;
 190                         case collect_compact_op:
 191                                 collect_compact(trace_contexts_p);
 192                                 break;
 193                         case collect_growing_heap_op:
 194                                 collect_growing_heap(requested_bytes,trace_contexts_p);
 195                                 break;
 196                         default:
 197                                 critical_error("Bad GC op",current_gc->op);
 198                                 break;
 199                         }
 200
 201                         break;
 202                 }
 203                 catch(const must_start_gc_again &)
 204                 {
 205                         /* We come back here if a generation is full */
 206                         start_gc_again();
 207                         continue;
 208                 }
 209         }
 210
 211         end_gc();
 212
 213         delete current_gc;
 214         current_gc = NULL;
 215
 216         set_fpu_state(fpu_state);
 217 }
 218
 219 /* primitive_minor_gc() is invoked by inline GC checks, and it needs to fill in
 220 uninitialized stack locations before actually calling the GC. See the comment
 221 in compiler.cfg.stacks.uninitialized for details. */
 222
 223 struct call_frame_scrubber {
 224         factor_vm *parent;
 225         context *ctx;
 226
 227         explicit call_frame_scrubber(factor_vm *parent_, context *ctx_) :
 228                 parent(parent_), ctx(ctx_) {}
 229
 230         void operator()(stack_frame *frame)
 231         {
 232                 cell return_address = parent->frame_offset(frame);
 233                 if(return_address == (cell)-1)
 234                         return;
 235
 236                 code_block *compiled = parent->frame_code(frame);
 237                 gc_info *info = compiled->block_gc_info();
 238
 239                 assert(return_address < compiled->size());
 240                 int index = info->return_address_index(return_address);
 241                 if(index != -1)
 242                         ctx->scrub_stacks(info,index);
 243         }
 244 };
 245
 246 void factor_vm::scrub_context(context *ctx)
 247 {
 248         call_frame_scrubber scrubber(this,ctx);
 249         iterate_callstack(ctx,scrubber);
 250 }
 251
 252 void factor_vm::scrub_contexts()
 253 {
 254         std::set<context *>::const_iterator begin = active_contexts.begin();
 255         std::set<context *>::const_iterator end = active_contexts.end();
 256         while(begin != end)
 257         {
 258                 scrub_context(*begin);
 259                 begin++;
 260         }
 261 }
 262
 263 void factor_vm::primitive_minor_gc()
 264 {
 265         scrub_contexts();
 266
 267         gc(collect_nursery_op,
 268                 0, /* requested size */
 269                 true /* trace contexts? */);
 270 }
 271
 272 void factor_vm::primitive_full_gc()
 273 {
 274         gc(collect_full_op,
 275                 0, /* requested size */
 276                 true /* trace contexts? */);
 277 }
 278
 279 void factor_vm::primitive_compact_gc()
 280 {
 281         gc(collect_compact_op,
 282                 0, /* requested size */
 283                 true /* trace contexts? */);
 284 }
 285
 286 /*
 287  * It is up to the caller to fill in the object's fields in a meaningful
 288  * fashion!
 289  */
 290 object *factor_vm::allot_large_object(cell type, cell size)
 291 {
 292         /* If tenured space does not have enough room, collect and compact */
 293         if(!data->tenured->can_allot_p(size))
 294         {
 295                 primitive_compact_gc();
 296
 297                 /* If it still won't fit, grow the heap */
 298                 if(!data->tenured->can_allot_p(size))
 299                 {
 300                         gc(collect_growing_heap_op,
 301                                 size, /* requested size */
 302                                 true /* trace contexts? */);
 303                 }
 304         }
 305
 306         object *obj = data->tenured->allot(size);
 307
 308         /* Allows initialization code to store old->new pointers
 309         without hitting the write barrier in the common case of
 310         a nursery allocation */
 311         write_barrier(obj,size);
 312
 313         obj->initialize(type);
 314         return obj;
 315 }
 316
 317 void factor_vm::primitive_enable_gc_events()
 318 {
 319         gc_events = new std::vector<gc_event>();
 320 }
 321
 322 void factor_vm::primitive_disable_gc_events()
 323 {
 324         if(gc_events)
 325         {
 326                 growable_array result(this);
 327
 328                 std::vector<gc_event> *gc_events = this->gc_events;
 329                 this->gc_events = NULL;
 330
 331                 std::vector<gc_event>::const_iterator iter = gc_events->begin();
 332                 std::vector<gc_event>::const_iterator end = gc_events->end();
 333
 334                 for(; iter != end; iter++)
 335                 {
 336                         gc_event event = *iter;
 337                         byte_array *obj = byte_array_from_value(&event);
 338                         result.add(tag<byte_array>(obj));
 339                 }
 340
 341                 result.trim();
 342                 ctx->push(result.elements.value());
 343
 344                 delete this->gc_events;
 345         }
 346         else
 347                 ctx->push(false_object);
 348 }
 349
 350 }