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         assert(!gc_off);
 149         assert(!current_gc);
 150
 151         current_gc = new gc_state(op,this);
 152
 153         /* Keep trying to GC higher and higher generations until we don't run out
 154         of space */
 155         for(;;)
 156         {
 157                 try
 158                 {
 159                         if(gc_events) current_gc->event->op = current_gc->op;
 160
 161                         switch(current_gc->op)
 162                         {
 163                         case collect_nursery_op:
 164                                 collect_nursery();
 165                                 break;
 166                         case collect_aging_op:
 167                                 collect_aging();
 168                                 if(data->high_fragmentation_p())
 169                                 {
 170                                         set_current_gc_op(collect_full_op);
 171                                         collect_full(trace_contexts_p);
 172                                 }
 173                                 break;
 174                         case collect_to_tenured_op:
 175                                 collect_to_tenured();
 176                                 if(data->high_fragmentation_p())
 177                                 {
 178                                         set_current_gc_op(collect_full_op);
 179                                         collect_full(trace_contexts_p);
 180                                 }
 181                                 break;
 182                         case collect_full_op:
 183                                 collect_full(trace_contexts_p);
 184                                 break;
 185                         case collect_compact_op:
 186                                 collect_compact(trace_contexts_p);
 187                                 break;
 188                         case collect_growing_heap_op:
 189                                 collect_growing_heap(requested_bytes,trace_contexts_p);
 190                                 break;
 191                         default:
 192                                 critical_error("Bad GC op",current_gc->op);
 193                                 break;
 194                         }
 195
 196                         break;
 197                 }
 198                 catch(const must_start_gc_again &)
 199                 {
 200                         /* We come back here if a generation is full */
 201                         start_gc_again();
 202                         continue;
 203                 }
 204         }
 205
 206         end_gc();
 207
 208         delete current_gc;
 209         current_gc = NULL;
 210 }
 211
 212 /* primitive_minor_gc() is invoked by inline GC checks, and it needs to fill in
 213 uninitialized stack locations before actually calling the GC. See the comment
 214 in compiler.cfg.stacks.uninitialized for details. */
 215
 216 struct call_frame_scrubber {
 217         factor_vm *parent;
 218         context *ctx;
 219
 220         explicit call_frame_scrubber(factor_vm *parent_, context *ctx_) :
 221                 parent(parent_), ctx(ctx_) {}
 222
 223         void operator()(stack_frame *frame)
 224         {
 225                 cell return_address = parent->frame_offset(frame);
 226                 if(return_address == (cell)-1)
 227                         return;
 228
 229                 code_block *compiled = parent->frame_code(frame);
 230                 gc_info *info = compiled->block_gc_info();
 231
 232                 assert(return_address < compiled->size());
 233                 cell index = info->return_address_index(return_address);
 234                 if(index != (cell)-1)
 235                         ctx->scrub_stacks(info,index);
 236         }
 237 };
 238
 239 void factor_vm::scrub_context(context *ctx)
 240 {
 241         call_frame_scrubber scrubber(this,ctx);
 242         iterate_callstack(ctx,scrubber);
 243 }
 244
 245 void factor_vm::scrub_contexts()
 246 {
 247         std::set<context *>::const_iterator begin = active_contexts.begin();
 248         std::set<context *>::const_iterator end = active_contexts.end();
 249         while(begin != end)
 250         {
 251                 scrub_context(*begin);
 252                 begin++;
 253         }
 254 }
 255
 256 void factor_vm::primitive_minor_gc()
 257 {
 258         scrub_contexts();
 259
 260         gc(collect_nursery_op,
 261                 0, /* requested size */
 262                 true /* trace contexts? */);
 263 }
 264
 265 void factor_vm::primitive_full_gc()
 266 {
 267         gc(collect_full_op,
 268                 0, /* requested size */
 269                 true /* trace contexts? */);
 270 }
 271
 272 void factor_vm::primitive_compact_gc()
 273 {
 274         gc(collect_compact_op,
 275                 0, /* requested size */
 276                 true /* trace contexts? */);
 277 }
 278
 279 /*
 280  * It is up to the caller to fill in the object's fields in a meaningful
 281  * fashion!
 282  */
 283 object *factor_vm::allot_large_object(cell type, cell size)
 284 {
 285         /* If tenured space does not have enough room, collect and compact */
 286         if(!data->tenured->can_allot_p(size))
 287         {
 288                 primitive_compact_gc();
 289
 290                 /* If it still won't fit, grow the heap */
 291                 if(!data->tenured->can_allot_p(size))
 292                 {
 293                         gc(collect_growing_heap_op,
 294                                 size, /* requested size */
 295                                 true /* trace contexts? */);
 296                 }
 297         }
 298
 299         object *obj = data->tenured->allot(size);
 300
 301         /* Allows initialization code to store old->new pointers
 302         without hitting the write barrier in the common case of
 303         a nursery allocation */
 304         write_barrier(obj,size);
 305
 306         obj->initialize(type);
 307         return obj;
 308 }
 309
 310 void factor_vm::primitive_enable_gc_events()
 311 {
 312         gc_events = new std::vector<gc_event>();
 313 }
 314
 315 void factor_vm::primitive_disable_gc_events()
 316 {
 317         if(gc_events)
 318         {
 319                 growable_array result(this);
 320
 321                 std::vector<gc_event> *gc_events = this->gc_events;
 322                 this->gc_events = NULL;
 323
 324                 std::vector<gc_event>::const_iterator iter = gc_events->begin();
 325                 std::vector<gc_event>::const_iterator end = gc_events->end();
 326
 327                 for(; iter != end; iter++)
 328                 {
 329                         gc_event event = *iter;
 330                         byte_array *obj = byte_array_from_value(&event);
 331                         result.add(tag<byte_array>(obj));
 332                 }
 333
 334                 result.trim();
 335                 ctx->push(result.elements.value());
 336
 337                 delete this->gc_events;
 338         }
 339         else
 340                 ctx->push(false_object);
 341 }
 342
 343 }