Fixing up fixed-size heaps

gc.c

@@ -528,8 +528,6 @@ size_t gc_convert_heap_page_to_free_list(gc_heap *h, gc_thread_data *thd)
  * @brief Sweep portion of the GC algorithm
  * @param h           Heap to sweep
  * @param heap_type   Type of heap, based on object sizes allocated on it
- * @param sum_freed_ptr Out parameter tracking the sum of freed data, in bytes.
- *                      This parameter is ignored if NULL is passed.
  * @param thd           Thread data object for the mutator using this heap
  * @return Return the size of the largest object freed, in bytes
  *
@@ -537,17 +535,17 @@ size_t gc_convert_heap_page_to_free_list(gc_heap *h, gc_thread_data *thd)
  * memory slots to the heap. It is only called by the collector thread after
  * the heap has been traced to identify live objects.
  */
-void gc_sweep_fixed_size(gc_heap * h, int heap_type, size_t * sum_freed_ptr, gc_thread_data *thd)
+gc_heap *gc_sweep_fixed_size(gc_heap * h, int heap_type, gc_thread_data *thd)
 {
 // TODO: all of this needs to be reworked, see gc_sweep
-  size_t heap_freed = 0, sum_freed = 0;
+  //size_t heap_freed = 0, sum_freed = 0;
   short heap_is_empty;
   object p;
   gc_free_list *q, *r, *s;
 #if GC_DEBUG_SHOW_SWEEP_DIAG
   gc_heap *orig_heap_ptr = h;
 #endif
-  gc_heap *prev_h = NULL;
+  //gc_heap *prev_h = NULL;
   gc_heap *rv = h;
 
   h->next_free = h;
@@ -561,7 +559,7 @@ void gc_sweep_fixed_size(gc_heap * h, int heap_type, size_t * sum_freed_ptr, gc_
 
     if (h->data_end != NULL) {
       // Special case, bump&pop heap
-      heap_freed = gc_convert_heap_page_to_free_list(h, thd);
+      gc_convert_heap_page_to_free_list(h, thd);
       heap_is_empty = 0; // For now, don't try to free bump&pop
     } else {
       //gc_free_list *next;
@@ -629,7 +627,7 @@ void gc_sweep_fixed_size(gc_heap * h, int heap_type, size_t * sum_freed_ptr, gc_
           }
 
           // free p
-          heap_freed += h->block_size;
+          //heap_freed += h->block_size;
           if (h->free_list == NULL) {
             // No free list, start one at p
             q = h->free_list = p;
@@ -650,7 +648,7 @@ void gc_sweep_fixed_size(gc_heap * h, int heap_type, size_t * sum_freed_ptr, gc_
             q->next = s;
             //printf("sweep reclaimed remaining=%d, %p, q=%p, r=%p\n", remaining, p, q, r);
           }
-
+          h->free_size += h->block_size;
         } else {
           //printf("sweep block is still used remaining=%d p = %p\n", remaining, p);
         }
@@ -749,7 +747,13 @@ gc_heap *gc_heap_free(gc_heap *page, gc_heap *prev_page)
 int gc_is_heap_empty(gc_heap *h) 
 {
   gc_free_list *f;
-  if (!h || !h->free_list) return 0;
+  if (!h) return 0;
+
+  if (h->data_end) { // Bump&pop
+    return (h->remaining == (h->size - (h->size % h->block_size)));
+  }
+
+  if (!h->free_list) return 0;
 
   f = h->free_list;
   if (f->size != 0 || !f->next) return 0;
@@ -1232,12 +1236,63 @@ void *gc_try_alloc_fixed_size(gc_heap * h, int heap_type, size_t size, char *obj
       ck_pr_sub_ptr(&(thd->cached_heap_free_sizes[heap_type]), size);
 
       h_passed->next_free = h;
+      h->free_size -= size;
       return result;
     }
   }
   return NULL;
 }
 
+void *gc_try_alloc_slow_fixed_size(gc_heap *h_passed, gc_heap *h, int heap_type, size_t size, char *obj, gc_thread_data *thd)
+{
+  gc_heap *h_start = h, *h_prev;
+  void *result = NULL;
+  // Find next heap
+  while (result == NULL) {
+    h_prev = h;
+    h = h->next;
+    if (h == NULL) {
+      // Wrap around to the first heap block
+      h_prev = NULL;
+      h = h_passed;
+    }
+    if (h == h_start) {
+      // Tried all and no heap exists with free space
+      break;
+    }
+    // check allocation status to make sure we can use it
+    if (h->is_full) {
+      continue; // Cannot sweep until next GC cycle
+    } else if (h->cached_free_size_status == 1 && !gc_is_heap_empty(h)) {
+      unsigned int h_size = h->size;
+      gc_heap *keep = gc_sweep_fixed_size(h, heap_type, thd); // Clean up garbage objects
+      if (!keep) {
+        // Heap marked for deletion, remove it and keep searching
+        gc_heap *freed = gc_heap_free(h, h_prev);
+        if (freed) {
+          if (h_prev) {
+            h = h_prev;
+          } else {
+            h = h_passed;
+          }
+          //thd->cached_heap_free_sizes[heap_type] -= prev_free_size;
+          thd->cached_heap_total_sizes[heap_type] -= h_size;
+          continue;
+        }
+      }
+    }
+    result = gc_try_alloc_fixed_size(h, heap_type, size, obj, thd);
+    if (result) {
+      h_passed->next_free = h;
+      h_passed->last_alloc_size = size;
+    } else {
+      // TODO: else, assign heap full? YES for fixed-size, for REST maybe not??
+      h->is_full = 1;
+    }
+  }
+  return result;
+}
+
 /**
  * @brief A convenience function for allocating bignums
  * @param data  The mutator's thread data object
@@ -1294,6 +1349,7 @@ void *gc_alloc(gc_heap_root * hrt, size_t size, char *obj, gc_thread_data * thd,
   gc_heap *h_passed, *h = NULL;
   int heap_type;
   void *(*try_alloc)(gc_heap * h, int heap_type, size_t size, char *obj, gc_thread_data * thd);
+  void *(*try_alloc_slow)(gc_heap *h_passed, gc_heap *h, int heap_type, size_t size, char *obj, gc_thread_data *thd);
   // TODO: check return value, if null (could not alloc) then 
   // run a collection and check how much free space there is. if less
   // the allowed ratio, try growing heap.
@@ -1302,26 +1358,29 @@ void *gc_alloc(gc_heap_root * hrt, size_t size, char *obj, gc_thread_data * thd,
   if (size <= 32) {
     heap_type = HEAP_SM;
     try_alloc = &gc_try_alloc_fixed_size;
+    try_alloc_slow = &gc_try_alloc_slow_fixed_size;
   } else if (size <= 64) {
     heap_type = HEAP_64;
     try_alloc = &gc_try_alloc_fixed_size;
+    try_alloc_slow = &gc_try_alloc_slow_fixed_size;
 // Only use this heap on 64-bit platforms, where larger objs are used more often
 // Code from http://stackoverflow.com/a/32717129/101258
 #if INTPTR_MAX == INT64_MAX
   } else if (size <= 96) {
     heap_type = HEAP_96;
     try_alloc = &gc_try_alloc_fixed_size;
+    try_alloc_slow = &gc_try_alloc_slow_fixed_size;
 #endif
   } else if (size >= MAX_STACK_OBJ) {
     heap_type = HEAP_HUGE;
     try_alloc = &gc_try_alloc;
+    try_alloc_slow = &gc_try_alloc_slow;
   } else {
     heap_type = HEAP_REST;
     try_alloc = &gc_try_alloc;
+    try_alloc_slow = &gc_try_alloc_slow;
   }
-TODO: in addition to below, probably need to update fixed size code to work with gc_heap_free_size and gc_is_heap_empty (though for that one we may just call another function in the fixed-size heap code
-
-TODO: convert fixed-size heap code and use that here. BUT, create a version of gc_alloc (maybe using macros?)
+//TODO: convert fixed-size heap code and use that here. BUT, create a version of gc_alloc (maybe using macros?)
 //that accepts heap type as an arg and can assume free lists. we can modify gc_move to use the proper new
 //version of gc_alloc (just ifdef if need be for 32 vs 64 bit. this might speed things up a bit
   h = hrt->heap[heap_type];
@@ -1341,7 +1400,7 @@ TODO: convert fixed-size heap code and use that here. BUT, create a version of g
   } else {
     // Slow path, find another heap block
     h->is_full = 1;
-    result = gc_try_alloc_slow(h_passed, h, heap_type, size, obj, thd);
+    result = try_alloc_slow(h_passed, h, heap_type, size, obj, thd);
 #if GC_DEBUG_VERBOSE
 fprintf(stderr, "slow alloc of %p\n", result);
 #endif
@@ -1361,7 +1420,7 @@ fprintf(stderr, "slow alloc of %p\n", result);
   // TODO: would be nice if gc_grow_heap returns new page (maybe it does) then we can start from there
   // otherwise will be a bit of a bottleneck since with lazy sweeping there is no guarantee we are at 
   // the end of the heap anymore
-      result = gc_try_alloc_slow(h_passed, h, heap_type, size, obj, thd);
+      result = try_alloc_slow(h_passed, h, heap_type, size, obj, thd);
 #if GC_DEBUG_VERBOSE
 fprintf(stderr, "slowest alloc of %p\n", result);
 #endif