gc-incremental.c

基于LWVCL开发的库

static
void
gcInvokeFinalizer(Collector* gcif)
{
  while (!finaliserStarted)
    KTHREAD(yield)();
  
  /* First invoke the GC */
  KGC_invoke(gcif, 1);
  
  /* Run the finalizer (if might already be running as a result of
   * the GC)
   */
  lockStaticMutex(&finman);
  if (finalRunning == false) {
    finalRunning = true;
    signalStaticCond(&finman); 
  }
  lockStaticMutex(&finmanend);
  unlockStaticMutex(&finman);
  waitStaticCond(&finmanend, (jlong)0);
  unlockStaticMutex(&finmanend);
}

/*
 * Allocate a new object.  The object is attached to the white queue.
 * After allocation, if incremental collection is active we peform
 * a little garbage collection.  If we finish it, we wakeup the garbage
 * collector.
 */

void throwOutOfMemory(void) NONRETURNING;

static
void*
gcMalloc(Collector* gcif, size_t size, gc_alloc_type_t fidx)
{
	gc_block* info;
	gc_unit* unit;
	void * volatile mem;	/* needed on SGI, see comment below */
	int i;
	size_t bsz;
	int times = 0;

	assert(gc_init != 0);
	assert(gcFunctions[fidx].description != NULL);
	assert(size != 0);
	assert(size > 0);

	size += sizeof(gc_unit);

	lockStaticMutex(&gc_lock);

	for (unit=NULL; unit==NULL;) {
		times++;
		unit = gc_heap_malloc(size);
	
		/* keep pointer to object */
		mem = UTOMEM(unit);
		if (unit == 0) {
			switch (times) {
			case 1:
				/* Try invoking GC if it is available */
				if (garbageman != 0) {
					unlockStaticMutex(&gc_lock);
					KGC_invoke(gcif, 0);
					lockStaticMutex(&gc_lock);
				}
				break;

			case 2:
				/* Grow the heap */
				DBG (GCSYSALLOC, dprintf ("growing heap by %u bytes of type %s (%2.1f%% free)\n", 
							  (unsigned int)size, gcFunctions[fidx].description,
							  (1.0 - ((double)gcStats.totalmem / gc_get_heap_total())) * 100.0); );
				
				gc_heap_grow(size);
				break;

			default:
				if (DBGEXPR(CATCHOUTOFMEM, true, false)) {
					/*
					 * If we ran out of memory, a OutOfMemoryException is
					 * thrown.  If we fail to allocate memory for it, all
					 * is lost.
					 */

					assert (!!!"Ran out of memory!");
				}
				/* Guess we've really run out */
				unlockStaticMutex(&gc_lock);
				return (NULL);
			}
		}
	}

	info = gc_mem2block(mem);
	i = GCMEM2IDX(info, unit);

	bsz = GCBLOCKSIZE(info);
	gcStats.totalmem += bsz;
	gcStats.totalobj += 1;
	gcStats.allocmem += bsz;
	gcStats.allocobj += 1;

	KGC_SET_FUNCS(info, i, fidx);

	OBJECTSTATSADD(unit);
	OBJECTSIZESADD(size);

	/* Determine whether we need to finalise or not */
	if (gcFunctions[fidx].final == KGC_OBJECT_NORMAL ||
	    gcFunctions[fidx].final == KGC_OBJECT_FIXED) {
		KGC_SET_STATE(info, i, KGC_STATE_NORMAL);
	}
	else {
		KGC_SET_STATE(info, i, KGC_STATE_NEEDFINALIZE);
	}

	/* If object is fixed, we give it the fixed colour and do not
	 * attach it to any lists.  This object is not part of the GC
	 * regime and must be freed explicitly.
	 */
	if (gcFunctions[fidx].final == KGC_OBJECT_FIXED) {
		addToCounter(&gcfixedmem, "gcmem-fixed objects", 1, bsz);
		KGC_SET_COLOUR(info, i, KGC_COLOUR_FIXED);
	}
	else {
		addToCounter(&gcgcablemem, "gcmem-gcable objects", 1, bsz);
		/*
		 * Note that as soon as we put the object on the white list,
		 * the gc might come along and free the object if it can't
		 * find any references to it.  This is why we need to keep
		 * a reference in `mem'.  Note that keeping a reference in
		 * `unit' will not do because markObject performs a UTOUNIT()!
		 * In addition, on some architectures (SGI), we must tell the
		 * compiler to not delay computing mem by defining it volatile.
		 */
		KGC_SET_COLOUR(info, i, KGC_COLOUR_WHITE);

		if (KGC_GET_STATE(info, i) == KGC_STATE_NEEDFINALIZE) {
			UAPPENDLIST(gclists[fin_white], unit);
		} else {
			UAPPENDLIST(gclists[nofin_white], unit);
		}
	}

	/* It is not safe to allocate java objects the first time
	 * gcMalloc is called, but it should be safe after gcEnable
	 * has been called.
	 */
	if (garbageman && !outOfMem && !outOfMem_allocator) {
		outOfMem_allocator = KTHREAD(current)();
	}

	unlockStaticMutex(&gc_lock);

	/* KTHREAD(current)() will be null in some window before we
	 * should try allocating java objects
	 */
	if (!outOfMem && outOfMem_allocator
	    && outOfMem_allocator == KTHREAD(current)()) { 
		outOfMem = OOM_ALLOCATING;
		outOfMem = OutOfMemoryError; /* implicit allocation */
		outOfMem_allocator = NULL;
		gc_add_ref(outOfMem);
	}
	return (mem);
}

static
struct Hjava_lang_Throwable *
gcThrowOOM(Collector *gcif UNUSED)
{
	Hjava_lang_Throwable *ret = NULL;
	int reffed;

	/*
	 * Make sure we are the only thread to use this exception
	 * object.
	 */
	lockStaticMutex(&gc_lock);
	ret = outOfMem;
	reffed = outOfMem != 0;
	outOfMem = NULL;
	/* We try allocating reserved pages before we allocate the
	 * outOfMemory error.  We can use some or all of the reserved
	 * pages to actually grab an error.
	 */
	if (gc_primitive_use_reserve()) {
		if (!ret || ret == OOM_ALLOCATING) {
			unlockStaticMutex(&gc_lock);
			ret = OutOfMemoryError; /* implicit allocation */
			lockStaticMutex(&gc_lock);
		}
	}
	if (ret == OOM_ALLOCATING || ret == NULL) {
		/* die now */
		unlockStaticMutex(&gc_lock);
		dprintf(
			"Not enough memory to throw OutOfMemoryError!\n");
		KAFFEVM_ABORT();
	}
	unlockStaticMutex(&gc_lock);
	if (reffed) gc_rm_ref(ret);
	return ret;
}

/*
 * Reallocate an object.
 */
static
void*
gcRealloc(Collector* gcif, void* mem, size_t size, gc_alloc_type_t fidx)
{
	gc_block* info;
	int idx;
	void* newmem;
	gc_unit* unit;
	size_t osize;

	assert(gcFunctions[fidx].final == KGC_OBJECT_FIXED);

	/* If nothing to realloc from, just allocate */
	if (mem == NULL) {
		return (gcMalloc(gcif, size, fidx));
	}

	lockStaticMutex(&gc_lock);
	unit = UTOUNIT(mem);
	info = gc_mem2block(unit);
	idx = GCMEM2IDX(info, unit);
	osize = GCBLOCKSIZE(info) - sizeof(gc_unit);

	assert(KGC_GET_FUNCS(info, idx) == fidx);

	/* Can only handled fixed objects at the moment */
	assert(KGC_GET_COLOUR(info, idx) == KGC_COLOUR_FIXED);
	info = NULL;
	unlockStaticMutex(&gc_lock);

	/* If we'll fit into the current space, just send it back */
	if (osize >= size) {
		return (mem);
	}

	/* Allocate new memory, copy data, and free the old */
	newmem = gcMalloc(gcif, size, fidx);
	memcpy(newmem, mem, (size_t)osize);
	gcFree(gcif, mem);

	return (newmem);
}

/*
 * Explicitly free an object.
 */
static
void
gcFree(Collector* gcif UNUSED, void* mem)
{
	gc_block* info;
	int idx;
	gc_unit* unit;

	if (mem != NULL) {
		lockStaticMutex(&gc_lock);
		unit = UTOUNIT(mem);
		info = gc_mem2block(unit);
		idx = GCMEM2IDX(info, unit);

		if (KGC_GET_COLOUR(info, idx) == KGC_COLOUR_FIXED) {
			size_t sz = GCBLOCKSIZE(info);
			
			OBJECTSTATSREMOVE(unit);

			/* Keep the stats correct */
			gcStats.totalmem -= sz;
			gcStats.totalobj -= 1;
			addToCounter(&gcfixedmem, "gcmem-fixed objects", 1, -(jlong)sz);

			gc_heap_free(unit);
		}
		else {
			assert(!!!"Attempt to explicitly free nonfixed object");
		}
		unlockStaticMutex(&gc_lock);
	}
}

static
void
gcInit(Collector *collector UNUSED)
{
	gc_init = 1;
}

/*
 * Start gc threads, which enable collection
 */
static 
void
/* ARGSUSED */
gcEnable(Collector* collector)
{
	errorInfo info;

        if (DBGEXPR(NOGC, false, true))
        {
                /* Start the GC daemons we need */
                finalman = createDaemon(&finaliserMan, "finaliser", 
				collector, THREAD_MAXPRIO,
					FINALIZERSTACKSIZE, &info);
                garbageman = createDaemon(&gcMan, "gc", 
				collector, THREAD_MAXPRIO,
					  GCSTACKSIZE, &info);
		assert(finalman && garbageman);
        }
}

#if defined(SUPPORT_VERBOSEMEM)

/* --------------------------------------------------------------------- */
/* The following functions are strictly for statistics gathering	 */

static
void
objectStatsChange(gc_unit* unit, int diff)
{
	gc_block* info;
	int idx;

	info = gc_mem2block(unit);
	idx = KGC_GET_FUNCS(info, GCMEM2IDX(info, unit));

	assert(idx >= 0 && gcFunctions[idx].description!=NULL);
	gcFunctions[idx].nr += diff * 1;
	gcFunctions[idx].mem += diff * GCBLOCKSIZE(info);
}

static
void
objectStatsPrint(void)
{
	int cnt = 0;

	dprintf("Memory statistics:\n");
	dprintf("------------------\n");

	while (cnt < KGC_ALLOC_MAX_INDEX) {
		dprintf("%14.14s: Nr %6d  Mem %6dK",
			gcFunctions[cnt].description, 
			gcFunctions[cnt].nr, 
			gcFunctions[cnt].mem/1024);
		if (++cnt % 2 != 0) {
			dprintf("   ");
		} else {
			dprintf("\n");
		}
	}

	if (cnt % 2 != 0) {
		dprintf("\n");
	}

        objectSizesPrint();
}

static
void
objectSizesAdd(size_t sz)
{
        int i;
        for (i = 0; objectSizes[i].size > 0 &&  sz > (size_t)objectSizes[i].size; i++)
                ;
        objectSizes[i].count++;

	/* This might be slightly misleading as it
	 * doesn't take into account the block overhead
	 * for small allocations */

	if (objectSizes[i].size > MAX_SMALL_OBJECT_SIZE) {
		objectSizes[i].total += sz;
	}
	else {
		objectSizes[i].total += objectSizes[i].size;
	}
}

static
void
objectSizesPrint(void)
{
        int i;
        uint64 total;
        int count;
        int nr;
        int j;

        total = 0;
        count = 0;
        for (i = 0; objectSizes[i].size != -1; i++) {
                count += objectSizes[i].count;
                total += objectSizes[i].total;
        }
        nr = i;

        if (total == 0) {
                return;
        }

        dprintf("Percentage size allocations: %% of allocation counts / %% of memory\n");
        dprintf("-----------------------------------------------------------------\n");


        for (i = 0; i < nr; ) {
                for (j = 0; j < 3 && i < nr; j++, i++) {
                        dprintf("%10zd :%5.1f /%5.1f  ", objectSizes[i].size, 
				(float)(objectSizes[i].count * 100 / (float)count), 
				(float)(objectSizes[i].total * 100 / (float)total));
                }
                dprintf("\n");
        }
}

#endif

static uintp
gcGetHeapLimit(Collector *gcif UNUSED)
{
  return gc_get_heap_limit();
}

static uintp
gcGetHeapTotal(Collector *gcif UNUSED)
{
  return gc_get_heap_total();
}

static uintp
gcGetHeapFree(Collector *gcif)
{
  return gcGetHeapTotal(gcif) - gcStats.totalmem;
}


static const char *
gcGetName(UNUSED Collector *gcif)
{
	return "kaffe-gc";
}

/*
 * vtable for object implementing the collector interface.
 */
static struct GarbageCollectorInterface_Ops KGC_Ops = {
	gcGetName,		/* reserved */
	NULL,		/* reserved */
	NULL,		/* reserved */
	gcMalloc,
	gcRealloc,
	gcFree,
	gcInvokeGC,
	gcInvokeFinalizer,
	gcInit,
	gcEnable,
	gcMarkAddress,
	gcMarkObject,
	gcGetObjectSize,
	gcGetObjectDescription,
	gcGetObjectIndex,
	gcGetObjectBase,
	gcRegisterFixedTypeByIndex,
	gcRegisterGcTypeByIndex,
	gcThrowOOM,
	gcEnableGC,
	gcDisableGC,
	gcGetHeapFree,
	gcGetHeapLimit,
	gcGetHeapTotal,
	KaffeGC_addRef,
	KaffeGC_rmRef,
	KaffeGC_addWeakRef,
	KaffeGC_rmWeakRef
};

/*
 * Initialise the Garbage Collection system.
 */
Collector* 
createGC(void)
{
  initStaticLock(&gcman);
  initStaticLock(&gcmanend);
  initStaticLock(&finman);
  initStaticLock(&finmanend);
  initStaticLock(&gc_lock);

  KaffeGC_initRefs();

  URESETLIST(gclists[nofin_white]);
  URESETLIST(gclists[fin_white]);
  URESETLIST(gclists[grey]);
  URESETLIST(gclists[nofin_black]);
  URESETLIST(gclists[fin_black]);
  URESETLIST(gclists[finalise]);
  gc_obj.collector.ops = &KGC_Ops;
  
  gc_heap_initialise ();
  gc_primitive_reserve(KGC_NUMBER_PAGE_IN_RESERVE);
  
  return (&gc_obj.collector);
}