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_), start_time(nano_count())
  84 {
  85         event = new gc_event(op,parent);
  86 }
  87
  88 gc_state::~gc_state()
  89 {
  90         delete event;
  91         event = NULL;
  92 }
  93
  94 void factor_vm::end_gc()
  95 {
  96         current_gc->event->ended_gc(this);
  97         if(gc_events) gc_events->push_back(*current_gc->event);
  98         delete current_gc->event;
  99         current_gc->event = NULL;
 100 }
 101
 102 void factor_vm::start_gc_again()
 103 {
 104         end_gc();
 105
 106         switch(current_gc->op)
 107         {
 108         case collect_nursery_op:
 109                 current_gc->op = collect_aging_op;
 110                 break;
 111         case collect_aging_op:
 112                 current_gc->op = collect_to_tenured_op;
 113                 break;
 114         case collect_to_tenured_op:
 115                 current_gc->op = collect_full_op;
 116                 break;
 117         case collect_full_op:
 118         case collect_compact_op:
 119                 current_gc->op = collect_growing_heap_op;
 120                 break;
 121         default:
 122                 critical_error("Bad GC op",current_gc->op);
 123                 break;
 124         }
 125
 126         current_gc->event = new gc_event(current_gc->op,this);
 127 }
 128
 129 void factor_vm::gc(gc_op op, cell requested_bytes, bool trace_contexts_p)
 130 {
 131         /* Save and reset FPU state before, restore it after, so that
 132         nano_count() doesn't bomb on Windows if inexact traps are enabled
 133         (fun huh?) */
 134         cell fpu_state = get_fpu_state();
 135
 136         assert(!gc_off);
 137         assert(!current_gc);
 138
 139         current_gc = new gc_state(op,this);
 140
 141         /* Keep trying to GC higher and higher generations until we don't run out
 142         of space */
 143         for(;;)
 144         {
 145                 try
 146                 {
 147                         current_gc->event->op = current_gc->op;
 148
 149                         switch(current_gc->op)
 150                         {
 151                         case collect_nursery_op:
 152                                 collect_nursery();
 153                                 break;
 154                         case collect_aging_op:
 155                                 collect_aging();
 156                                 if(data->high_fragmentation_p())
 157                                 {
 158                                         current_gc->op = collect_full_op;
 159                                         current_gc->event->op = collect_full_op;
 160                                         collect_full(trace_contexts_p);
 161                                 }
 162                                 break;
 163                         case collect_to_tenured_op:
 164                                 collect_to_tenured();
 165                                 if(data->high_fragmentation_p())
 166                                 {
 167                                         current_gc->op = collect_full_op;
 168                                         current_gc->event->op = collect_full_op;
 169                                         collect_full(trace_contexts_p);
 170                                 }
 171                                 break;
 172                         case collect_full_op:
 173                                 collect_full(trace_contexts_p);
 174                                 break;
 175                         case collect_compact_op:
 176                                 collect_compact(trace_contexts_p);
 177                                 break;
 178                         case collect_growing_heap_op:
 179                                 collect_growing_heap(requested_bytes,trace_contexts_p);
 180                                 break;
 181                         default:
 182                                 critical_error("Bad GC op",current_gc->op);
 183                                 break;
 184                         }
 185
 186                         break;
 187                 }
 188                 catch(const must_start_gc_again &)
 189                 {
 190                         /* We come back here if a generation is full */
 191                         start_gc_again();
 192                         continue;
 193                 }
 194         }
 195
 196         end_gc();
 197
 198         delete current_gc;
 199         current_gc = NULL;
 200
 201         set_fpu_state(fpu_state);
 202 }
 203
 204 /* primitive_minor_gc() is invoked by inline GC checks, and it needs to fill in
 205 uninitialized stack locations before actually calling the GC. See the comment
 206 in compiler.cfg.stacks.uninitialized for details. */
 207
 208 struct call_frame_scrubber {
 209         factor_vm *parent;
 210         context *ctx;
 211
 212         explicit call_frame_scrubber(factor_vm *parent_, context *ctx_) :
 213                 parent(parent_), ctx(ctx_) {}
 214
 215         void operator()(stack_frame *frame)
 216         {
 217                 cell return_address = parent->frame_offset(frame);
 218                 if(return_address == (cell)-1)
 219                         return;
 220
 221                 code_block *compiled = parent->frame_code(frame);
 222                 gc_info *info = compiled->block_gc_info();
 223
 224                 assert(return_address < compiled->size());
 225                 int index = info->return_address_index(return_address);
 226                 if(index != -1)
 227                         ctx->scrub_stacks(info,index);
 228         }
 229 };
 230
 231 void factor_vm::scrub_context(context *ctx)
 232 {
 233         call_frame_scrubber scrubber(this,ctx);
 234         iterate_callstack(ctx,scrubber);
 235 }
 236
 237 void factor_vm::scrub_contexts()
 238 {
 239         std::set<context *>::const_iterator begin = active_contexts.begin();
 240         std::set<context *>::const_iterator end = active_contexts.end();
 241         while(begin != end)
 242         {
 243                 scrub_context(*begin);
 244                 begin++;
 245         }
 246 }
 247
 248 void factor_vm::primitive_minor_gc()
 249 {
 250         scrub_contexts();
 251
 252         gc(collect_nursery_op,
 253                 0, /* requested size */
 254                 true /* trace contexts? */);
 255 }
 256
 257 void factor_vm::primitive_full_gc()
 258 {
 259         gc(collect_full_op,
 260                 0, /* requested size */
 261                 true /* trace contexts? */);
 262 }
 263
 264 void factor_vm::primitive_compact_gc()
 265 {
 266         gc(collect_compact_op,
 267                 0, /* requested size */
 268                 true /* trace contexts? */);
 269 }
 270
 271 /*
 272  * It is up to the caller to fill in the object's fields in a meaningful
 273  * fashion!
 274  */
 275 object *factor_vm::allot_large_object(cell type, cell size)
 276 {
 277         /* If tenured space does not have enough room, collect and compact */
 278         if(!data->tenured->can_allot_p(size))
 279         {
 280                 primitive_compact_gc();
 281
 282                 /* If it still won't fit, grow the heap */
 283                 if(!data->tenured->can_allot_p(size))
 284                 {
 285                         gc(collect_growing_heap_op,
 286                                 size, /* requested size */
 287                                 true /* trace contexts? */);
 288                 }
 289         }
 290
 291         object *obj = data->tenured->allot(size);
 292
 293         /* Allows initialization code to store old->new pointers
 294         without hitting the write barrier in the common case of
 295         a nursery allocation */
 296         write_barrier(obj,size);
 297
 298         obj->initialize(type);
 299         return obj;
 300 }
 301
 302 void factor_vm::primitive_enable_gc_events()
 303 {
 304         gc_events = new std::vector<gc_event>();
 305 }
 306
 307 void factor_vm::primitive_disable_gc_events()
 308 {
 309         if(gc_events)
 310         {
 311                 growable_array result(this);
 312
 313                 std::vector<gc_event> *gc_events = this->gc_events;
 314                 this->gc_events = NULL;
 315
 316                 std::vector<gc_event>::const_iterator iter = gc_events->begin();
 317                 std::vector<gc_event>::const_iterator end = gc_events->end();
 318
 319                 for(; iter != end; iter++)
 320                 {
 321                         gc_event event = *iter;
 322                         byte_array *obj = byte_array_from_value(&event);
 323                         result.add(tag<byte_array>(obj));
 324                 }
 325
 326                 result.trim();
 327                 ctx->push(result.elements.value());
 328
 329                 delete this->gc_events;
 330         }
 331         else
 332                 ctx->push(false_object);
 333 }
 334
 335 }